From 7382c0d74fbb5004eecdf54575f63e9ee2cb3a0e Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Tue, 23 Jun 2015 18:57:23 +0100
Subject: [PATCH 01/15] Work out canonical names for libraries, and put them in
 special #include comments.

---
 app/src/processing/app/Sketch.java            | 10 +++-
 .../libraries/ContributedLibrary.java         |  8 ++-
 .../processing/app/packages/UserLibrary.java  | 60 +++++++++++++++++++
 3 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/app/src/processing/app/Sketch.java b/app/src/processing/app/Sketch.java
index 2bdcfedda31..0f6a5e702f4 100644
--- a/app/src/processing/app/Sketch.java
+++ b/app/src/processing/app/Sketch.java
@@ -931,14 +931,14 @@ public boolean addFile(File sourceFile) {
 
 
   public void importLibrary(UserLibrary lib) throws IOException {
-    importLibrary(lib.getSrcFolder());
+    importLibrary(lib.getSrcFolder(), lib.getDepSpec());
   }
 
   /**
    * Add import statements to the current tab for all of packages inside
    * the specified jar file.
    */
-  private void importLibrary(File jarPath) throws IOException {
+  private void importLibrary(File jarPath, String depSpec) throws IOException {
     // make sure the user didn't hide the sketch folder
     ensureExistence();
 
@@ -960,7 +960,11 @@ private void importLibrary(File jarPath) throws IOException {
     for (String aList : list) {
       buffer.append("#include <");
       buffer.append(aList);
-      buffer.append(">\n");
+      buffer.append(">");
+      if (depSpec != null) {
+	buffer.append(" //!Lib '" + depSpec + "'");
+      }
+      buffer.append("\n");
     }
     buffer.append('\n');
     buffer.append(editor.getText());
diff --git a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
index af42a493b89..66164830ae7 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
@@ -39,6 +39,8 @@
 
 public abstract class ContributedLibrary extends DownloadableContribution {
 
+  public abstract String getGlobalName();
+
   public abstract String getName();
 
   public abstract String getMaintainer();
@@ -142,10 +144,10 @@ public boolean equals(Object obj) {
     boolean versionEquals = thisVersion == otherVersion ||
       (thisVersion != null && otherVersion != null && thisVersion.equals(otherVersion));
 
-    String thisName = getName();
-    String otherName = ((ContributedLibrary) obj).getName();
+    String thisName = getGlobalName();
+    String otherName = ((ContributedLibrary) obj).getGlobalName();
 
-    boolean nameEquals = thisName == null || otherName == null || thisName.equals(otherName);
+    boolean nameEquals = thisName != null && otherName != null && thisName.equals(otherName);
 
     return versionEquals && nameEquals;
   }
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index ef24022abd9..f60db141a21 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -37,11 +37,13 @@
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 
 public class UserLibrary extends ContributedLibrary {
 
+  private String globalName;
   private String name;
   private String version;
   private String author;
@@ -151,6 +153,12 @@ public static UserLibrary create(File libFolder) throws IOException {
     }
 
     UserLibrary res = new UserLibrary();
+
+    String globalName = properties.get("global_name");
+    if (globalName != null) {
+      globalName = globalName.trim();
+    }
+
     res.setInstalledFolder(libFolder);
     res.setInstalled(true);
     res.name = properties.get("name").trim();
@@ -165,9 +173,60 @@ public static UserLibrary create(File libFolder) throws IOException {
     res.architectures = archs;
     res.layout = layout;
     res.declaredTypes = typesList;
+    res.setGlobalName(globalName);
     return res;
   }
 
+  /**
+   * Call this after setting website, author, and name.
+   */
+  public void setGlobalName(String gn) {
+    globalName = gn;
+    boolean invalid = false;
+    if (globalName == null) {
+      invalid = true;
+      String rest = website.replaceFirst(".*://", "").replaceFirst("\\.[^/.]*$", "");
+      List<String> parts = Arrays.asList(rest.split("/"));
+      List<String> hostParts = Arrays.asList(parts.get(0).split("\\."));
+      Collections.reverse(hostParts);
+      globalName = String.join(".", hostParts);
+      if (globalName.endsWith(".www")) {
+        // Remove www component
+        globalName = globalName.substring(0, globalName.length() - 4);
+      }
+      if (parts.size() > 1) {
+        // Path parts
+        globalName += "." + String.join(".", parts.subList(1, parts.size()));
+      }
+      if (globalName.startsWith("com.github.")) { 
+        // Better to use the user-only namespace.
+        globalName = "io.github." + globalName.substring(11);
+      }
+    }
+    if (globalName.equals("")) {
+      invalid = true;
+      // Fallback.  Note: the global name is used to test for equality,
+      // so it must have a value, and for the sake of legacy libraries, it
+      // should include the name more or less as-is.
+      globalName = author.replace('/', '_') + "/" + name;
+    }
+    if (invalid) {
+      System.err.println("WARNING: global_name not set in library " + name + ". Guessing '" + globalName + "'.\nPlease set this to a suitable Java-style package name, e.g. io.github.myaccount.myproject\nThe name should be set manually to avoid confusion when forking.");
+    }
+  }
+
+  @Override
+  public String getGlobalName() {
+    return globalName;
+  }
+
+  public String getDepSpec() {
+    if (globalName != null && version != null) {
+      return globalName + ":" + version;
+    }
+    return null;
+  }
+
   @Override
   public String getName() {
     return name;
@@ -289,6 +348,7 @@ public boolean useRecursion() {
   @Override
   public String toString() {
     String res = "Library: " + name + "\n";
+    res += "         (global_name=" + globalName + ")\n";
     res += "         (version=" + version + ")\n";
     res += "         (author=" + author + ")\n";
     res += "         (maintainer=" + maintainer + ")\n";

From c3c57478b5fc3f429f958202de700f54ff1c46cc Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Wed, 24 Jun 2015 20:07:40 +0100
Subject: [PATCH 02/15] Show library information when hover over #include
 statement.

---
 .../processing/app/syntax/SketchTextArea.java | 24 +++++++++++++++++++
 .../src/processing/app/BaseNoGui.java         | 17 +++++++++++++
 .../app/preproc/PdePreprocessor.java          |  9 ++-----
 3 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index fbd9e0c7c16..5b67561184a 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -39,6 +39,7 @@
 import org.fife.ui.rtextarea.RTextAreaUI;
 import org.fife.ui.rtextarea.RUndoManager;
 import processing.app.*;
+import processing.app.packages.UserLibrary;
 
 import javax.swing.*;
 import javax.swing.event.EventListenerList;
@@ -396,6 +397,7 @@ public void mouseMoved(MouseEvent e) {
         t = new TokenImpl(t);
       }
       Cursor c2;
+      String tipText = null;
       if (t != null && t.isHyperlink()) {
         if (hoveredOverLinkOffset == -1 ||
           hoveredOverLinkOffset != t.getOffset()) {
@@ -432,12 +434,34 @@ public void mouseMoved(MouseEvent e) {
         c2 = Cursor.getPredefinedCursor(Cursor.TEXT_CURSOR);
         hoveredOverLinkOffset = -1;
         //  linkGeneratorResult = null;
+
+        int pos = viewToModel(e.getPoint());
+        if (pos > -1) {
+          int lineNo = -1;
+          try {
+            lineNo = getLineOfOffset(pos);
+          } catch (BadLocationException ex) {}
+          String line = getTextLine(lineNo);
+          if (line != null) {
+            UserLibrary lib = BaseNoGui.firstLibraryByCode(line);
+            if (lib != null) {
+              String ver = lib.getVersion();
+              if (ver != null) {
+                ver = " " + ver;
+              } else {
+                ver = "";
+              }
+              tipText = lib.getName() + ver + ": " + lib.getSrcFolder().toString();
+            }
+          }
+        }
       }
       if (getCursor() != c2) {
         setCursor(c2);
         // TODO: Repaint just the affected line(s).
         repaint(); // Link either left or went into.
       }
+      setToolTipText(tipText);
     }
 
     private void stopScanningForLinks() {
diff --git a/arduino-core/src/processing/app/BaseNoGui.java b/arduino-core/src/processing/app/BaseNoGui.java
index 8aeffcc157b..19dbfc30f32 100644
--- a/arduino-core/src/processing/app/BaseNoGui.java
+++ b/arduino-core/src/processing/app/BaseNoGui.java
@@ -19,6 +19,7 @@
 import processing.app.legacy.PApplet;
 import processing.app.packages.LibraryList;
 import processing.app.packages.UserLibrary;
+import processing.app.preproc.PdePreprocessor;
 
 import java.io.*;
 import java.net.URISyntaxException;
@@ -962,6 +963,22 @@ static public void populateImportToLibraryTable() {
     }
   }
 
+  static public UserLibrary firstLibraryByImport(String importName) {
+    LibraryList list = importToLibraryTable.get(importName);
+    if (list == null || list.isEmpty()) {
+      return null;
+    }
+    return list.peekFirst();
+  }
+
+  static public UserLibrary firstLibraryByCode(String code) {
+    List<String> incs = PdePreprocessor.findIncludes(code);
+    if (incs.isEmpty()) {
+      return null;
+    }
+    return firstLibraryByImport(incs.get(0));
+  }
+
   static public void initParameters(String args[]) throws IOException {
     String preferencesFile = null;
 
diff --git a/arduino-core/src/processing/app/preproc/PdePreprocessor.java b/arduino-core/src/processing/app/preproc/PdePreprocessor.java
index dc30922a92e..e8d97962d67 100644
--- a/arduino-core/src/processing/app/preproc/PdePreprocessor.java
+++ b/arduino-core/src/processing/app/preproc/PdePreprocessor.java
@@ -97,13 +97,8 @@ public int writePrefix(String program)
     }
 
     //String importRegexp = "(?:^|\\s|;)(import\\s+)(\\S+)(\\s*;)";
-    programImports = new ArrayList<String>();
 
-    String[][] pieces = PApplet.matchAll(program, IMPORT_REGEX);
-
-    if (pieces != null)
-      for (int i = 0; i < pieces.length; i++)
-        programImports.add(pieces[i][1]);  // the package name
+    programImports = findIncludes(program);
 
     codeFolderImports = new ArrayList<String>();
 //    if (codeFolderPackages != null) {
@@ -127,7 +122,7 @@ public static List<String> findIncludes(String code){
    
     String[][] pieces = PApplet.matchAll(code, IMPORT_REGEX);
 
-    ArrayList programImports = new ArrayList<String>();
+    ArrayList<String> programImports = new ArrayList<>();
     
     if (pieces != null)
       for (int i = 0; i < pieces.length; i++)

From d395a6b269397aaa16f85b6d919bca962b81e322 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Wed, 24 Jun 2015 21:54:10 +0100
Subject: [PATCH 03/15] Get hierarchical deps, and show in tooltips.

Also, ensure that legacy libraries have a global name.
---
 .../processing/app/syntax/SketchTextArea.java | 38 +++++++++++++-----
 .../libraries/ContributedLibrary.java         |  4 ++
 .../src/processing/app/BaseNoGui.java         | 16 ++++++++
 .../src/processing/app/debug/Compiler.java    | 31 ++++++++++++++
 .../app/packages/LegacyUserLibrary.java       |  1 +
 .../processing/app/packages/UserLibrary.java  | 40 ++++++++++++++++---
 6 files changed, 115 insertions(+), 15 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index 5b67561184a..7d820222887 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -40,6 +40,7 @@
 import org.fife.ui.rtextarea.RUndoManager;
 import processing.app.*;
 import processing.app.packages.UserLibrary;
+import cc.arduino.contributions.libraries.ContributedLibrary;
 
 import javax.swing.*;
 import javax.swing.event.EventListenerList;
@@ -443,16 +444,7 @@ public void mouseMoved(MouseEvent e) {
           } catch (BadLocationException ex) {}
           String line = getTextLine(lineNo);
           if (line != null) {
-            UserLibrary lib = BaseNoGui.firstLibraryByCode(line);
-            if (lib != null) {
-              String ver = lib.getVersion();
-              if (ver != null) {
-                ver = " " + ver;
-              } else {
-                ver = "";
-              }
-              tipText = lib.getName() + ver + ": " + lib.getSrcFolder().toString();
-            }
+            tipText = getImportInfo(line);
           }
         }
       }
@@ -464,6 +456,32 @@ public void mouseMoved(MouseEvent e) {
       setToolTipText(tipText);
     }
 
+    private String getImportInfo(String line) {
+      UserLibrary lib = BaseNoGui.firstLibraryByCode(line);
+      String info = null;
+      if (lib != null) {
+        info = getLibDescription(lib);
+        for (ContributedLibrary recLib : lib.getRequiredLibsRec()) {
+          info += "\n* " + getLibDescription(recLib);
+        }
+      }
+      return info;
+    }
+
+    private String getLibDescription(ContributedLibrary lib) {
+      String ver = lib.getVersion();
+      if (ver != null) {
+        ver = " " + ver;
+      } else {
+        ver = "";
+      }
+      String folder = "";
+      if (lib instanceof UserLibrary) {
+        folder = ": " + ((UserLibrary) lib).getSrcFolder().toString();
+      }
+      return lib.getName() + " (" + lib.getGlobalName() + ")" + ver + folder;
+    }
+
     private void stopScanningForLinks() {
       if (isScanningForLinks) {
         Cursor c = getCursor();
diff --git a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
index 66164830ae7..6ca88686850 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
@@ -65,6 +65,10 @@ public abstract class ContributedLibrary extends DownloadableContribution {
 
   public abstract List<ContributedLibraryReference> getRequires();
 
+  public abstract List<ContributedLibrary> getRequiredLibs();
+
+  public abstract List<ContributedLibrary> getRequiredLibsRec();
+
   public static final Comparator<ContributedLibrary> CASE_INSENSITIVE_ORDER = (o1, o2) -> o1.getName().compareToIgnoreCase(o2.getName());
 
   /**
diff --git a/arduino-core/src/processing/app/BaseNoGui.java b/arduino-core/src/processing/app/BaseNoGui.java
index 19dbfc30f32..dac3bde3461 100644
--- a/arduino-core/src/processing/app/BaseNoGui.java
+++ b/arduino-core/src/processing/app/BaseNoGui.java
@@ -979,6 +979,22 @@ static public UserLibrary firstLibraryByCode(String code) {
     return firstLibraryByImport(incs.get(0));
   }
 
+  static public List<UserLibrary> librariesByCode(String code) throws IOException {
+    List<UserLibrary> libs = new ArrayList<>();
+    List<String> incs = PdePreprocessor.findIncludes(code);
+    for (String inc : incs) {
+      UserLibrary lib = firstLibraryByImport(inc);
+      if (lib != null) {
+        libs.add(lib);
+      }
+    }
+    return libs;
+  }
+
+  static public List<UserLibrary> librariesByCode(File file) throws IOException {
+    return librariesByCode(FileUtils.readFileToString(file));
+  }
+
   static public void initParameters(String args[]) throws IOException {
     String preferencesFile = null;
 
diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index 5f1bf9ad567..f628226ff2b 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -32,6 +32,7 @@
 import cc.arduino.packages.BoardPort;
 import cc.arduino.packages.Uploader;
 import cc.arduino.packages.UploaderFactory;
+import cc.arduino.contributions.libraries.ContributedLibrary;
 
 import cc.arduino.packages.uploaders.MergeSketchWithBooloader;
 import org.apache.commons.compress.utils.IOUtils;
@@ -608,6 +609,36 @@ private PreferencesMap createBuildPreferences(String _buildPath,
     return p;
   }
 
+  static public List<File> findAllSources(File sourcePath, boolean recurse) {
+    List<File> allSources = new ArrayList<>();
+    allSources.addAll(findFilesInFolder(sourcePath, "S", recurse));
+    allSources.addAll(findFilesInFolder(sourcePath, "c", recurse));
+    allSources.addAll(findFilesInFolder(sourcePath, "cpp", recurse));
+    allSources.addAll(findFilesInFolder(sourcePath, "h", recurse));
+    allSources.addAll(findFilesInFolder(sourcePath, "hh", recurse));
+    allSources.addAll(findFilesInFolder(sourcePath, "hpp", recurse));
+    return allSources;
+  }
+
+  static public List<ContributedLibrary> findRequiredLibs(File sourcePath, boolean recurse) {
+    List<File> files = findAllSources(sourcePath, recurse);
+    List<ContributedLibrary> result = new ArrayList<>();
+    for (File file : files) {
+      List<UserLibrary> libs = null;
+      try { 
+        libs = BaseNoGui.librariesByCode(file);
+      } catch (IOException e) {
+        continue;
+      }
+      for (ContributedLibrary lib : libs) {
+        if (!result.contains(lib)) {
+          result.add(lib);
+        }
+      }
+    }
+    return result;
+  }
+
   private List<File> compileFiles(File outputPath, File sourcePath,
                                   boolean recurse, List<File> includeFolders)
           throws RunnerException, PreferencesMapException {
diff --git a/arduino-core/src/processing/app/packages/LegacyUserLibrary.java b/arduino-core/src/processing/app/packages/LegacyUserLibrary.java
index 56a86ccb9c7..e5abc53776c 100644
--- a/arduino-core/src/processing/app/packages/LegacyUserLibrary.java
+++ b/arduino-core/src/processing/app/packages/LegacyUserLibrary.java
@@ -43,6 +43,7 @@ public static LegacyUserLibrary create(File libFolder) {
     res.setInstalled(true);
     res.layout = LibraryLayout.FLAT;
     res.name = libFolder.getName();
+    res.globalName = res.name;
     res.setTypes(Arrays.asList("Contributed"));
     res.setCategory("Uncategorized");
     return res;
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index f60db141a21..f3588075ad6 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -32,6 +32,7 @@
 import cc.arduino.contributions.libraries.ContributedLibraryReference;
 import processing.app.helpers.FileUtils;
 import processing.app.helpers.PreferencesMap;
+import processing.app.debug.Compiler;
 
 import java.io.File;
 import java.io.IOException;
@@ -43,7 +44,7 @@
 
 public class UserLibrary extends ContributedLibrary {
 
-  private String globalName;
+  protected String globalName;
   private String name;
   private String version;
   private String author;
@@ -183,7 +184,7 @@ public static UserLibrary create(File libFolder) throws IOException {
   public void setGlobalName(String gn) {
     globalName = gn;
     boolean invalid = false;
-    if (globalName == null) {
+    if (globalName == null || globalName.equals("")) {
       invalid = true;
       String rest = website.replaceFirst(".*://", "").replaceFirst("\\.[^/.]*$", "");
       List<String> parts = Arrays.asList(rest.split("/"));
@@ -203,11 +204,10 @@ public void setGlobalName(String gn) {
         globalName = "io.github." + globalName.substring(11);
       }
     }
-    if (globalName.equals("")) {
+    if (globalName == null || globalName.equals("")) {
       invalid = true;
       // Fallback.  Note: the global name is used to test for equality,
-      // so it must have a value, and for the sake of legacy libraries, it
-      // should include the name more or less as-is.
+      // so it must have a value.
       globalName = author.replace('/', '_') + "/" + name;
     }
     if (invalid) {
@@ -320,6 +320,36 @@ public List<ContributedLibraryReference> getRequires() {
     return null;
   }
 
+  private List<ContributedLibrary> requiredLibs = null;
+  private List<ContributedLibrary> requiredLibsRec = null;
+
+  @Override
+  public List<ContributedLibrary> getRequiredLibs() {
+    if (requiredLibs == null) {
+      requiredLibs = Compiler.findRequiredLibs(getSrcFolder(), useRecursion());
+      requiredLibs.remove(this);
+    }
+    return requiredLibs;
+  }
+
+  @Override
+  public List<ContributedLibrary> getRequiredLibsRec() {
+    if (requiredLibsRec == null) {
+      requiredLibsRec = new ArrayList<>();
+      for (ContributedLibrary lib : getRequiredLibs()) {
+        if (!requiredLibsRec.contains(lib) && lib != this) {
+          requiredLibsRec.add(lib);
+          for (ContributedLibrary libRec : lib.getRequiredLibsRec()) {
+            if (!requiredLibsRec.contains(libRec) && libRec != this) {
+              requiredLibsRec.add(libRec);
+            }
+          }
+        }
+      }
+    }
+    return requiredLibsRec;
+  }
+
   public List<String> getDeclaredTypes() {
     return declaredTypes;
   }

From d8758c0b4a9aa399643a55c00053a94246554b10 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 10:37:08 +0100
Subject: [PATCH 04/15] If version is null, omit from dep spec rather than
 returning null.

---
 .../src/processing/app/packages/UserLibrary.java       | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index f3588075ad6..d142bd58f00 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -221,10 +221,14 @@ public String getGlobalName() {
   }
 
   public String getDepSpec() {
-    if (globalName != null && version != null) {
-      return globalName + ":" + version;
+    String depSpec = null;
+    if (globalName != null) {
+      depSpec = globalName;
+      if (version != null) {
+        depSpec += ":" + version;
+      }
     }
-    return null;
+    return depSpec;
   }
 
   @Override

From 968803ff007c7426d540b00ec90c4b898ab458f2 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 11:43:53 +0100
Subject: [PATCH 05/15] Update cached dependency information when libraries
 change their dependencies.

---
 .../processing/app/packages/UserLibrary.java  | 41 ++++++++++++++++++-
 1 file changed, 39 insertions(+), 2 deletions(-)

diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index d142bd58f00..4f945c55f9c 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -41,6 +41,8 @@
 import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.TreeMap;
+import java.util.Map;
 
 public class UserLibrary extends ContributedLibrary {
 
@@ -324,12 +326,47 @@ public List<ContributedLibraryReference> getRequires() {
     return null;
   }
 
+  private Map<String,long[]> lastUpdateTimes = new TreeMap<String,long[]>();
+
   private List<ContributedLibrary> requiredLibs = null;
   private List<ContributedLibrary> requiredLibsRec = null;
 
+  private boolean changedSinceLastUpdate(int idx) {
+    List<File> files = Compiler.findAllSources(getSrcFolder(), useRecursion());
+    // Important: must update timestamps from ALL files before returning.
+    boolean changed = false;
+    for (File file : files) {
+      String fname = file.toString();
+      long modTime = file.lastModified();
+      if (!lastUpdateTimes.containsKey(fname)) {
+        long[] times = new long[2];
+        times[idx] = modTime;
+        lastUpdateTimes.put(fname, times);
+        changed = true;
+      } else if (lastUpdateTimes.get(fname)[idx] < modTime) {
+        lastUpdateTimes.get(fname)[idx] = modTime;
+        changed = true;
+      }
+    }
+    return changed;
+  }
+
+  private boolean changedSinceLastUpdateRec(int idx) {
+    if (changedSinceLastUpdate(idx)) {
+      return true;
+    }
+    for (ContributedLibrary lib : getRequiredLibs()) {
+      if (lib instanceof UserLibrary &&
+          ((UserLibrary) lib).changedSinceLastUpdateRec(idx)) {
+        return true;
+      }
+    }
+    return false;
+  }
+
   @Override
   public List<ContributedLibrary> getRequiredLibs() {
-    if (requiredLibs == null) {
+    if (requiredLibs == null || changedSinceLastUpdate(0)) {
       requiredLibs = Compiler.findRequiredLibs(getSrcFolder(), useRecursion());
       requiredLibs.remove(this);
     }
@@ -338,7 +375,7 @@ public List<ContributedLibrary> getRequiredLibs() {
 
   @Override
   public List<ContributedLibrary> getRequiredLibsRec() {
-    if (requiredLibsRec == null) {
+    if (requiredLibsRec == null || changedSinceLastUpdateRec(1)) {
       requiredLibsRec = new ArrayList<>();
       for (ContributedLibrary lib : getRequiredLibs()) {
         if (!requiredLibsRec.contains(lib) && lib != this) {

From 1ff501fc26b576111f475d4a16e4205ba7765fd2 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 13:17:26 +0100
Subject: [PATCH 06/15] Prevent infinite recursion caused by dependency loops.

---
 .../libraries/ContributedLibrary.java         |  5 ++++
 .../processing/app/packages/UserLibrary.java  | 29 +++++++++++++++----
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
index 6ca88686850..ea2968e0a1c 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
@@ -34,6 +34,7 @@
 
 import java.util.Comparator;
 import java.util.List;
+import java.util.SortedSet;
 
 import static processing.app.I18n._;
 
@@ -69,6 +70,10 @@ public abstract class ContributedLibrary extends DownloadableContribution {
 
   public abstract List<ContributedLibrary> getRequiredLibsRec();
 
+  public abstract List<ContributedLibrary> getRequiredLibsRec(SortedSet<String> visited);
+
+  public abstract boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited);
+
   public static final Comparator<ContributedLibrary> CASE_INSENSITIVE_ORDER = (o1, o2) -> o1.getName().compareToIgnoreCase(o2.getName());
 
   /**
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index 4f945c55f9c..3db05bd6c5b 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -43,6 +43,8 @@
 import java.util.List;
 import java.util.TreeMap;
 import java.util.Map;
+import java.util.TreeSet;
+import java.util.SortedSet;
 
 public class UserLibrary extends ContributedLibrary {
 
@@ -351,13 +353,19 @@ private boolean changedSinceLastUpdate(int idx) {
     return changed;
   }
 
-  private boolean changedSinceLastUpdateRec(int idx) {
+  @Override
+  public boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited) {
+    // Prevent infinite recursion.
+    if (visited.contains(getDepSpec())) {
+      return false;
+    }
+    visited.add(getDepSpec());
+
     if (changedSinceLastUpdate(idx)) {
       return true;
     }
     for (ContributedLibrary lib : getRequiredLibs()) {
-      if (lib instanceof UserLibrary &&
-          ((UserLibrary) lib).changedSinceLastUpdateRec(idx)) {
+      if (lib.changedSinceLastUpdateRec(idx, visited)) {
         return true;
       }
     }
@@ -375,12 +383,23 @@ public List<ContributedLibrary> getRequiredLibs() {
 
   @Override
   public List<ContributedLibrary> getRequiredLibsRec() {
-    if (requiredLibsRec == null || changedSinceLastUpdateRec(1)) {
+    return getRequiredLibsRec(new TreeSet<>());
+  }
+
+  @Override
+  public List<ContributedLibrary> getRequiredLibsRec(SortedSet<String> visited) {
+    // Prevent infinite recursion.
+    if (visited.contains(getDepSpec())) {
+      return new ArrayList<>();
+    }
+    visited.add(getDepSpec());
+
+    if (requiredLibsRec == null || changedSinceLastUpdateRec(1, new TreeSet<>(visited))) {
       requiredLibsRec = new ArrayList<>();
       for (ContributedLibrary lib : getRequiredLibs()) {
         if (!requiredLibsRec.contains(lib) && lib != this) {
           requiredLibsRec.add(lib);
-          for (ContributedLibrary libRec : lib.getRequiredLibsRec()) {
+          for (ContributedLibrary libRec : lib.getRequiredLibsRec(visited)) {
             if (!requiredLibsRec.contains(libRec) && libRec != this) {
               requiredLibsRec.add(libRec);
             }

From 6e883ab301ec07f26e64268330303794915a6506 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 13:40:19 +0100
Subject: [PATCH 07/15] Use UserLibrary instead of ContributedLibrary.

---
 .../processing/app/syntax/SketchTextArea.java |  7 +++----
 .../libraries/ContributedLibrary.java         |  8 --------
 .../src/processing/app/debug/Compiler.java    |  7 +++----
 .../processing/app/packages/UserLibrary.java  | 20 ++++++++-----------
 4 files changed, 14 insertions(+), 28 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index 7d820222887..9a32223be94 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -40,7 +40,6 @@
 import org.fife.ui.rtextarea.RUndoManager;
 import processing.app.*;
 import processing.app.packages.UserLibrary;
-import cc.arduino.contributions.libraries.ContributedLibrary;
 
 import javax.swing.*;
 import javax.swing.event.EventListenerList;
@@ -461,14 +460,14 @@ private String getImportInfo(String line) {
       String info = null;
       if (lib != null) {
         info = getLibDescription(lib);
-        for (ContributedLibrary recLib : lib.getRequiredLibsRec()) {
+        for (UserLibrary recLib : lib.getRequiredLibsRec()) {
           info += "\n* " + getLibDescription(recLib);
         }
       }
       return info;
     }
 
-    private String getLibDescription(ContributedLibrary lib) {
+    private String getLibDescription(UserLibrary lib) {
       String ver = lib.getVersion();
       if (ver != null) {
         ver = " " + ver;
@@ -477,7 +476,7 @@ private String getLibDescription(ContributedLibrary lib) {
       }
       String folder = "";
       if (lib instanceof UserLibrary) {
-        folder = ": " + ((UserLibrary) lib).getSrcFolder().toString();
+        folder = ": " + lib.getSrcFolder().toString();
       }
       return lib.getName() + " (" + lib.getGlobalName() + ")" + ver + folder;
     }
diff --git a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
index ea2968e0a1c..444a114d1f1 100644
--- a/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
+++ b/arduino-core/src/cc/arduino/contributions/libraries/ContributedLibrary.java
@@ -66,14 +66,6 @@ public abstract class ContributedLibrary extends DownloadableContribution {
 
   public abstract List<ContributedLibraryReference> getRequires();
 
-  public abstract List<ContributedLibrary> getRequiredLibs();
-
-  public abstract List<ContributedLibrary> getRequiredLibsRec();
-
-  public abstract List<ContributedLibrary> getRequiredLibsRec(SortedSet<String> visited);
-
-  public abstract boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited);
-
   public static final Comparator<ContributedLibrary> CASE_INSENSITIVE_ORDER = (o1, o2) -> o1.getName().compareToIgnoreCase(o2.getName());
 
   /**
diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index f628226ff2b..aa01bb28ff4 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -32,7 +32,6 @@
 import cc.arduino.packages.BoardPort;
 import cc.arduino.packages.Uploader;
 import cc.arduino.packages.UploaderFactory;
-import cc.arduino.contributions.libraries.ContributedLibrary;
 
 import cc.arduino.packages.uploaders.MergeSketchWithBooloader;
 import org.apache.commons.compress.utils.IOUtils;
@@ -620,9 +619,9 @@ static public List<File> findAllSources(File sourcePath, boolean recurse) {
     return allSources;
   }
 
-  static public List<ContributedLibrary> findRequiredLibs(File sourcePath, boolean recurse) {
+  static public List<UserLibrary> findRequiredLibs(File sourcePath, boolean recurse) {
     List<File> files = findAllSources(sourcePath, recurse);
-    List<ContributedLibrary> result = new ArrayList<>();
+    List<UserLibrary> result = new ArrayList<>();
     for (File file : files) {
       List<UserLibrary> libs = null;
       try { 
@@ -630,7 +629,7 @@ static public List<ContributedLibrary> findRequiredLibs(File sourcePath, boolean
       } catch (IOException e) {
         continue;
       }
-      for (ContributedLibrary lib : libs) {
+      for (UserLibrary lib : libs) {
         if (!result.contains(lib)) {
           result.add(lib);
         }
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index 3db05bd6c5b..03a9b1fdd4c 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -330,8 +330,8 @@ public List<ContributedLibraryReference> getRequires() {
 
   private Map<String,long[]> lastUpdateTimes = new TreeMap<String,long[]>();
 
-  private List<ContributedLibrary> requiredLibs = null;
-  private List<ContributedLibrary> requiredLibsRec = null;
+  private List<UserLibrary> requiredLibs = null;
+  private List<UserLibrary> requiredLibsRec = null;
 
   private boolean changedSinceLastUpdate(int idx) {
     List<File> files = Compiler.findAllSources(getSrcFolder(), useRecursion());
@@ -353,7 +353,6 @@ private boolean changedSinceLastUpdate(int idx) {
     return changed;
   }
 
-  @Override
   public boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited) {
     // Prevent infinite recursion.
     if (visited.contains(getDepSpec())) {
@@ -364,7 +363,7 @@ public boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited) {
     if (changedSinceLastUpdate(idx)) {
       return true;
     }
-    for (ContributedLibrary lib : getRequiredLibs()) {
+    for (UserLibrary lib : getRequiredLibs()) {
       if (lib.changedSinceLastUpdateRec(idx, visited)) {
         return true;
       }
@@ -372,8 +371,7 @@ public boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited) {
     return false;
   }
 
-  @Override
-  public List<ContributedLibrary> getRequiredLibs() {
+  public List<UserLibrary> getRequiredLibs() {
     if (requiredLibs == null || changedSinceLastUpdate(0)) {
       requiredLibs = Compiler.findRequiredLibs(getSrcFolder(), useRecursion());
       requiredLibs.remove(this);
@@ -381,13 +379,11 @@ public List<ContributedLibrary> getRequiredLibs() {
     return requiredLibs;
   }
 
-  @Override
-  public List<ContributedLibrary> getRequiredLibsRec() {
+  public List<UserLibrary> getRequiredLibsRec() {
     return getRequiredLibsRec(new TreeSet<>());
   }
 
-  @Override
-  public List<ContributedLibrary> getRequiredLibsRec(SortedSet<String> visited) {
+  public List<UserLibrary> getRequiredLibsRec(SortedSet<String> visited) {
     // Prevent infinite recursion.
     if (visited.contains(getDepSpec())) {
       return new ArrayList<>();
@@ -396,10 +392,10 @@ public List<ContributedLibrary> getRequiredLibsRec(SortedSet<String> visited) {
 
     if (requiredLibsRec == null || changedSinceLastUpdateRec(1, new TreeSet<>(visited))) {
       requiredLibsRec = new ArrayList<>();
-      for (ContributedLibrary lib : getRequiredLibs()) {
+      for (UserLibrary lib : getRequiredLibs()) {
         if (!requiredLibsRec.contains(lib) && lib != this) {
           requiredLibsRec.add(lib);
-          for (ContributedLibrary libRec : lib.getRequiredLibsRec(visited)) {
+          for (UserLibrary libRec : lib.getRequiredLibsRec(visited)) {
             if (!requiredLibsRec.contains(libRec) && libRec != this) {
               requiredLibsRec.add(libRec);
             }

From 7f43ca6f1d5cb294fd82ebc3d907536abb5767d4 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 14:32:30 +0100
Subject: [PATCH 08/15] Change method names.

---
 app/src/processing/app/syntax/SketchTextArea.java  |  2 +-
 arduino-core/src/processing/app/BaseNoGui.java     | 14 +++++++-------
 .../src/processing/app/debug/Compiler.java         |  2 +-
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index 9a32223be94..a7de1f5b395 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -456,7 +456,7 @@ public void mouseMoved(MouseEvent e) {
     }
 
     private String getImportInfo(String line) {
-      UserLibrary lib = BaseNoGui.firstLibraryByCode(line);
+      UserLibrary lib = BaseNoGui.findFirstLibraryByCode(line);
       String info = null;
       if (lib != null) {
         info = getLibDescription(lib);
diff --git a/arduino-core/src/processing/app/BaseNoGui.java b/arduino-core/src/processing/app/BaseNoGui.java
index dac3bde3461..b000bc5e376 100644
--- a/arduino-core/src/processing/app/BaseNoGui.java
+++ b/arduino-core/src/processing/app/BaseNoGui.java
@@ -963,7 +963,7 @@ static public void populateImportToLibraryTable() {
     }
   }
 
-  static public UserLibrary firstLibraryByImport(String importName) {
+  static public UserLibrary findFirstLibraryByImport(String importName) {
     LibraryList list = importToLibraryTable.get(importName);
     if (list == null || list.isEmpty()) {
       return null;
@@ -971,19 +971,19 @@ static public UserLibrary firstLibraryByImport(String importName) {
     return list.peekFirst();
   }
 
-  static public UserLibrary firstLibraryByCode(String code) {
+  static public UserLibrary findFirstLibraryByCode(String code) {
     List<String> incs = PdePreprocessor.findIncludes(code);
     if (incs.isEmpty()) {
       return null;
     }
-    return firstLibraryByImport(incs.get(0));
+    return findFirstLibraryByImport(incs.get(0));
   }
 
-  static public List<UserLibrary> librariesByCode(String code) throws IOException {
+  static public List<UserLibrary> findLibrariesByCode(String code) throws IOException {
     List<UserLibrary> libs = new ArrayList<>();
     List<String> incs = PdePreprocessor.findIncludes(code);
     for (String inc : incs) {
-      UserLibrary lib = firstLibraryByImport(inc);
+      UserLibrary lib = findFirstLibraryByImport(inc);
       if (lib != null) {
         libs.add(lib);
       }
@@ -991,8 +991,8 @@ static public List<UserLibrary> librariesByCode(String code) throws IOException
     return libs;
   }
 
-  static public List<UserLibrary> librariesByCode(File file) throws IOException {
-    return librariesByCode(FileUtils.readFileToString(file));
+  static public List<UserLibrary> findLibrariesByCode(File file) throws IOException {
+    return findLibrariesByCode(FileUtils.readFileToString(file));
   }
 
   static public void initParameters(String args[]) throws IOException {
diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index aa01bb28ff4..55a1530b90a 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -625,7 +625,7 @@ static public List<UserLibrary> findRequiredLibs(File sourcePath, boolean recurs
     for (File file : files) {
       List<UserLibrary> libs = null;
       try { 
-        libs = BaseNoGui.librariesByCode(file);
+        libs = BaseNoGui.findLibrariesByCode(file);
       } catch (IOException e) {
         continue;
       }

From cedea25aaf7751a04d47c369e654d13797ad27d0 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 14:54:22 +0100
Subject: [PATCH 09/15] Add recursive dependencies to a build.

---
 arduino-core/src/processing/app/debug/Compiler.java | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index 55a1530b90a..aae82169c91 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -1395,6 +1395,12 @@ public void preprocess(String buildPath, PdePreprocessor preprocessor) throws Ru
             importedDuplicateHeaders.add(item);
             importedDuplicateLibraries.add(list);
           }
+          // Add recursive dependencies
+          for (UserLibrary libRec : lib.getRequiredLibsRec()) {
+            if (!importedLibraries.contains(libRec)) {
+              importedLibraries.add(libRec);
+            }
+          }
         }
       }
     }

From 7fce54d51e6e01d87f415d9b41525155d2f97d28 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 22:14:34 +0100
Subject: [PATCH 10/15] Use dependency spec to find correct library.

---
 .../processing/app/syntax/SketchTextArea.java | 10 +--
 .../src/processing/app/BaseNoGui.java         | 42 ++++++-----
 .../src/processing/app/debug/Compiler.java    | 62 +++++++++-------
 .../app/packages/LibrarySelection.java        | 26 +++++++
 .../processing/app/packages/UserLibrary.java  | 70 +++++++++++++++----
 .../app/preproc/PdePreprocessor.java          | 23 +++---
 6 files changed, 163 insertions(+), 70 deletions(-)
 create mode 100644 arduino-core/src/processing/app/packages/LibrarySelection.java

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index a7de1f5b395..b6558795aeb 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -40,6 +40,7 @@
 import org.fife.ui.rtextarea.RUndoManager;
 import processing.app.*;
 import processing.app.packages.UserLibrary;
+import processing.app.packages.LibrarySelection;
 
 import javax.swing.*;
 import javax.swing.event.EventListenerList;
@@ -456,12 +457,13 @@ public void mouseMoved(MouseEvent e) {
     }
 
     private String getImportInfo(String line) {
-      UserLibrary lib = BaseNoGui.findFirstLibraryByCode(line);
+      LibrarySelection libSel = BaseNoGui.findLibraryByCode(line);
       String info = null;
-      if (lib != null) {
+      if (libSel != null) {
+        UserLibrary lib = libSel.get();
         info = getLibDescription(lib);
-        for (UserLibrary recLib : lib.getRequiredLibsRec()) {
-          info += "\n* " + getLibDescription(recLib);
+        for (LibrarySelection recLibSel : lib.getRequiredLibsRec()) {
+          info += "\n* " + getLibDescription(recLibSel.get());
         }
       }
       return info;
diff --git a/arduino-core/src/processing/app/BaseNoGui.java b/arduino-core/src/processing/app/BaseNoGui.java
index b000bc5e376..8169a10c6ea 100644
--- a/arduino-core/src/processing/app/BaseNoGui.java
+++ b/arduino-core/src/processing/app/BaseNoGui.java
@@ -18,6 +18,7 @@
 import processing.app.helpers.filefilters.OnlyFilesWithExtension;
 import processing.app.legacy.PApplet;
 import processing.app.packages.LibraryList;
+import processing.app.packages.LibrarySelection;
 import processing.app.packages.UserLibrary;
 import processing.app.preproc.PdePreprocessor;
 
@@ -851,10 +852,10 @@ static private void createToolPreferences(ContributionsIndexer indexer) {
   }
 
   static public void populateImportToLibraryTable() {
-    // Populate importToLibraryTable. Each header filename maps to
-    // a list of libraries. Compiler.java will use only the first
-    // library on each list. The others are used only to advise
-    // user of ambiguously matched and duplicate libraries.
+    // Populate importToLibraryTable. Each header filename maps to a list of
+    // libraries. Compiler.java will use the dependency specs in the source
+    // files to decide which library to use from the list. The list is also
+    // used to advise user of ambiguously matched and duplicate libraries.
     importToLibraryTable = new HashMap<String, LibraryList>();
     for (UserLibrary lib : librariesIndexer.getInstalledLibraries()) {
       try {
@@ -963,27 +964,36 @@ static public void populateImportToLibraryTable() {
     }
   }
 
-  static public UserLibrary findFirstLibraryByImport(String importName) {
-    LibraryList list = importToLibraryTable.get(importName);
+  static public LibrarySelection findLibraryByImport(String[] importSpec) {
+    LibraryList list = importToLibraryTable.get(importSpec[0]);
     if (list == null || list.isEmpty()) {
       return null;
     }
-    return list.peekFirst();
+    int index = 0;
+    if (importSpec[1] != null) {
+      for (int i = 0; i < list.size(); i++) {
+        if (list.get(i).matchesDepSpec(importSpec[1])) {
+          index = i;
+        }
+      }
+    }
+    return new LibrarySelection(list, index);
   }
 
-  static public UserLibrary findFirstLibraryByCode(String code) {
-    List<String> incs = PdePreprocessor.findIncludes(code);
+  static public LibrarySelection findLibraryByCode(String code) {
+    List<String[]> incs = PdePreprocessor.findIncludes(code);
     if (incs.isEmpty()) {
       return null;
     }
-    return findFirstLibraryByImport(incs.get(0));
+    return findLibraryByImport(incs.get(0));
   }
 
-  static public List<UserLibrary> findLibrariesByCode(String code) throws IOException {
-    List<UserLibrary> libs = new ArrayList<>();
-    List<String> incs = PdePreprocessor.findIncludes(code);
-    for (String inc : incs) {
-      UserLibrary lib = findFirstLibraryByImport(inc);
+  static public List<LibrarySelection> findLibrariesByCode(String code)
+  throws IOException {
+    List<LibrarySelection> libs = new ArrayList<>();
+    List<String[]> incs = PdePreprocessor.findIncludes(code);
+    for (String[] inc : incs) {
+      LibrarySelection lib = findLibraryByImport(inc);
       if (lib != null) {
         libs.add(lib);
       }
@@ -991,7 +1001,7 @@ static public List<UserLibrary> findLibrariesByCode(String code) throws IOExcept
     return libs;
   }
 
-  static public List<UserLibrary> findLibrariesByCode(File file) throws IOException {
+  static public List<LibrarySelection> findLibrariesByCode(File file) throws IOException {
     return findLibrariesByCode(FileUtils.readFileToString(file));
   }
 
diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index aae82169c91..932762a5ced 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -48,6 +48,7 @@
 import processing.app.legacy.PApplet;
 import processing.app.packages.LegacyUserLibrary;
 import processing.app.packages.UserLibrary;
+import processing.app.packages.LibrarySelection;
 import processing.app.tools.DoubleQuotedArgumentsOnWindowsCommandLine;
 
 public class Compiler implements MessageConsumer {
@@ -489,12 +490,15 @@ private void adviseDuplicateLibraries() {
       System.out.println(I18n.format(_("Multiple libraries were found for \"{0}\""),
         importedDuplicateHeaders.get(i)));
       boolean first = true;
-      for (UserLibrary lib : importedDuplicateLibraries.get(i)) {
-        if (first) {
-          System.out.println(I18n.format(_(" Used: {0}"),
-            lib.getInstalledFolder().getPath()));
-          first = false;
-        } else {
+      LibrarySelection libSel = importedDuplicateLibraries.get(i);
+
+      System.out.println(I18n.format(_(" Used: {0}"),
+        libSel.get().getInstalledFolder().getPath()));
+      first = false;
+
+      for (int j = 0; j < libSel.getList().size(); j++) {
+        if (j != libSel.getIndex()) {
+          UserLibrary lib = libSel.getList().get(j);
           System.out.println(I18n.format(_(" Not used: {0}"),
             lib.getInstalledFolder().getPath()));
         }
@@ -619,19 +623,19 @@ static public List<File> findAllSources(File sourcePath, boolean recurse) {
     return allSources;
   }
 
-  static public List<UserLibrary> findRequiredLibs(File sourcePath, boolean recurse) {
+  static public List<LibrarySelection> findRequiredLibs(File sourcePath, boolean recurse) {
     List<File> files = findAllSources(sourcePath, recurse);
-    List<UserLibrary> result = new ArrayList<>();
+    List<LibrarySelection> result = new ArrayList<>();
     for (File file : files) {
-      List<UserLibrary> libs = null;
+      List<LibrarySelection> libSels = null;
       try { 
-        libs = BaseNoGui.findLibrariesByCode(file);
+        libSels = BaseNoGui.findLibrariesByCode(file);
       } catch (IOException e) {
         continue;
       }
-      for (UserLibrary lib : libs) {
-        if (!result.contains(lib)) {
-          result.add(lib);
+      for (LibrarySelection libSel : libSels) {
+        if (!result.contains(libSel)) {
+          result.add(libSel);
         }
       }
     }
@@ -1383,22 +1387,26 @@ public void preprocess(String buildPath, PdePreprocessor preprocessor) throws Ru
     // grab the imports from the code just preproc'd
 
     importedLibraries = new LibraryList();
-    importedDuplicateHeaders = new ArrayList<String>();
-    importedDuplicateLibraries = new ArrayList<LibraryList>();
-    for (String item : preprocessor.getExtraImports()) {
-      LibraryList list = BaseNoGui.importToLibraryTable.get(item);
-      if (list != null) {
-        UserLibrary lib = list.peekFirst();
-        if (lib != null && !importedLibraries.contains(lib)) {
+    importedDuplicateHeaders = new ArrayList<>();
+    importedDuplicateLibraries = new ArrayList<>();
+    for (String[] item : preprocessor.getExtraImports()) {
+      LibrarySelection libSel = BaseNoGui.findLibraryByImport(item);
+      if (libSel != null) {
+        UserLibrary lib = libSel.get();
+        if (!importedLibraries.contains(lib)) {
           importedLibraries.add(lib);
-          if (list.size() > 1) {
-            importedDuplicateHeaders.add(item);
-            importedDuplicateLibraries.add(list);
+          if (libSel.getList().size() > 1) {
+            importedDuplicateHeaders.add(item[0]);
+            importedDuplicateLibraries.add(libSel);
           }
           // Add recursive dependencies
-          for (UserLibrary libRec : lib.getRequiredLibsRec()) {
-            if (!importedLibraries.contains(libRec)) {
-              importedLibraries.add(libRec);
+          for (LibrarySelection libSelRec : lib.getRequiredLibsRec()) {
+            if (!importedLibraries.contains(libSelRec.get())) {
+              importedLibraries.add(libSelRec.get());
+              if (libSelRec.getList().size() > 1) {
+                importedDuplicateHeaders.add("UNKNOWN"); // FIXME
+                importedDuplicateLibraries.add(libSelRec);
+              }
             }
           }
         }
@@ -1434,7 +1442,7 @@ public void preprocess(String buildPath, PdePreprocessor preprocessor) throws Ru
    */
   private LibraryList importedLibraries;
   private List<String>      importedDuplicateHeaders;
-  private List<LibraryList> importedDuplicateLibraries;
+  private List<LibrarySelection> importedDuplicateLibraries;
 
   /**
    * Map an error from a set of processed .java files back to its location
diff --git a/arduino-core/src/processing/app/packages/LibrarySelection.java b/arduino-core/src/processing/app/packages/LibrarySelection.java
new file mode 100644
index 00000000000..417024ef10b
--- /dev/null
+++ b/arduino-core/src/processing/app/packages/LibrarySelection.java
@@ -0,0 +1,26 @@
+package processing.app.packages;
+
+public class LibrarySelection {
+  private LibraryList list;
+  private int index;
+  public LibrarySelection(LibraryList list, int index) {
+    this.list = list;
+    this.index = index;
+  }
+  public UserLibrary get() {
+    return list.get(index);
+  }
+  public LibraryList getList() {
+    return list;
+  }
+  public int getIndex() {
+    return index;
+  }
+  public boolean equals(Object otherObj) {
+    if (!(otherObj instanceof LibrarySelection)) {
+      return false;
+    }
+    LibrarySelection other = (LibrarySelection) otherObj;
+    return this.get().equals(other.get());
+  }
+}
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index 03a9b1fdd4c..e15ce109ca9 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -30,6 +30,7 @@
 
 import cc.arduino.contributions.libraries.ContributedLibrary;
 import cc.arduino.contributions.libraries.ContributedLibraryReference;
+import processing.app.packages.LibrarySelection;
 import processing.app.helpers.FileUtils;
 import processing.app.helpers.PreferencesMap;
 import processing.app.debug.Compiler;
@@ -235,6 +236,49 @@ public String getDepSpec() {
     return depSpec;
   }
 
+  public boolean matchesDepSpec(String spec) {
+    String[] parts = spec.split(":", 2);
+    if (!getGlobalName().equals(parts[0])) {
+      // Global name does not match - reject.
+      return false;
+    }
+    if (parts.length == 1) {
+      // No version spec - accept any version.
+      return true;
+    }
+    if (getVersion() == null) {
+      // Unlabeled version - fails to match any version spec.
+      return false;
+    }
+    String[] vers = parts[1].split("-");
+    if (vers.length == 2) {
+      return versionsOrdered(vers[0], getVersion()) &&
+             versionsOrdered(getVersion(), vers[1]);
+    } else if (parts[1].endsWith("+")) {
+      return versionsOrdered(parts[1].substring(0, parts[1].length() - 1), getVersion());
+    } else if (parts[1].endsWith("*")) {
+      return getVersion().startsWith(parts[1].substring(0, parts[1].length() - 1));
+    } else {
+      return parts[1].equals(getVersion());
+    }
+  }
+
+  private boolean versionsOrdered(String ver1, String ver2) {
+    String[] c1 = ver1.split("\\.");
+    String[] c2 = ver2.split("\\.");
+    int i;
+    for (i = 0; i < c1.length && i < c2.length; i++) {
+      int n1 = Integer.parseInt(c1[i]);
+      int n2 = Integer.parseInt(c2[i]);
+      if (n1 > n2) {
+        return false;
+      } else if (n1 < n2) {
+        return true;
+      }
+    }
+    return c1.length <= c2.length;
+  }
+
   @Override
   public String getName() {
     return name;
@@ -330,8 +374,8 @@ public List<ContributedLibraryReference> getRequires() {
 
   private Map<String,long[]> lastUpdateTimes = new TreeMap<String,long[]>();
 
-  private List<UserLibrary> requiredLibs = null;
-  private List<UserLibrary> requiredLibsRec = null;
+  private List<LibrarySelection> requiredLibs = null;
+  private List<LibrarySelection> requiredLibsRec = null;
 
   private boolean changedSinceLastUpdate(int idx) {
     List<File> files = Compiler.findAllSources(getSrcFolder(), useRecursion());
@@ -363,15 +407,15 @@ public boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited) {
     if (changedSinceLastUpdate(idx)) {
       return true;
     }
-    for (UserLibrary lib : getRequiredLibs()) {
-      if (lib.changedSinceLastUpdateRec(idx, visited)) {
+    for (LibrarySelection libSel : getRequiredLibs()) {
+      if (libSel.get().changedSinceLastUpdateRec(idx, visited)) {
         return true;
       }
     }
     return false;
   }
 
-  public List<UserLibrary> getRequiredLibs() {
+  public List<LibrarySelection> getRequiredLibs() {
     if (requiredLibs == null || changedSinceLastUpdate(0)) {
       requiredLibs = Compiler.findRequiredLibs(getSrcFolder(), useRecursion());
       requiredLibs.remove(this);
@@ -379,11 +423,11 @@ public List<UserLibrary> getRequiredLibs() {
     return requiredLibs;
   }
 
-  public List<UserLibrary> getRequiredLibsRec() {
+  public List<LibrarySelection> getRequiredLibsRec() {
     return getRequiredLibsRec(new TreeSet<>());
   }
 
-  public List<UserLibrary> getRequiredLibsRec(SortedSet<String> visited) {
+  public List<LibrarySelection> getRequiredLibsRec(SortedSet<String> visited) {
     // Prevent infinite recursion.
     if (visited.contains(getDepSpec())) {
       return new ArrayList<>();
@@ -392,12 +436,12 @@ public List<UserLibrary> getRequiredLibsRec(SortedSet<String> visited) {
 
     if (requiredLibsRec == null || changedSinceLastUpdateRec(1, new TreeSet<>(visited))) {
       requiredLibsRec = new ArrayList<>();
-      for (UserLibrary lib : getRequiredLibs()) {
-        if (!requiredLibsRec.contains(lib) && lib != this) {
-          requiredLibsRec.add(lib);
-          for (UserLibrary libRec : lib.getRequiredLibsRec(visited)) {
-            if (!requiredLibsRec.contains(libRec) && libRec != this) {
-              requiredLibsRec.add(libRec);
+      for (LibrarySelection libSel : getRequiredLibs()) {
+        if (!requiredLibsRec.contains(libSel) && libSel.get() != this) {
+          requiredLibsRec.add(libSel);
+          for (LibrarySelection libSelRec : libSel.get().getRequiredLibsRec(visited)) {
+            if (!requiredLibsRec.contains(libSelRec) && libSelRec.get() != this) {
+              requiredLibsRec.add(libSelRec);
             }
           }
         }
diff --git a/arduino-core/src/processing/app/preproc/PdePreprocessor.java b/arduino-core/src/processing/app/preproc/PdePreprocessor.java
index e8d97962d67..0a8b56034d7 100644
--- a/arduino-core/src/processing/app/preproc/PdePreprocessor.java
+++ b/arduino-core/src/processing/app/preproc/PdePreprocessor.java
@@ -43,7 +43,7 @@ Processing version Copyright (c) 2004-05 Ben Fry and Casey Reas
  */
 public class PdePreprocessor {
   
-  private static final String IMPORT_REGEX = "^\\s*#include\\s*[<\"](\\S+)[\">]";
+  private static final String IMPORT_REGEX = "^\\s*#include\\s*[<\"](\\S+)[\">](?:[ \\t]*//!Lib[ \\t]+[\"']([^\"']*)[\"'])?";
   
   // stores number of built user-defined function prototypes
   public int prototypeCount = 0;
@@ -58,7 +58,7 @@ public class PdePreprocessor {
   // these ones have the .* at the end, since a class name might be at the end
   // instead of .* which would make trouble other classes using this can lop
   // off the . and anything after it to produce a package name consistently.
-  List<String> programImports;
+  List<String[]> programImports;
 
   // imports just from the code folder, treated differently
   // than the others, since the imports are auto-generated.
@@ -85,6 +85,12 @@ public int writePrefix(String program)
     // http://dev.processing.org/bugs/show_bug.cgi?id=5
     program += "\n";
 
+    //String importRegexp = "(?:^|\\s|;)(import\\s+)(\\S+)(\\s*;)";
+
+    // This must come before scrubbing the comments, so that we get the
+    // dependency specs (//!Lib comments)
+    programImports = findIncludes(program);
+
     // if the program ends with an unterminated multi-line comment,
     // an OutOfMemoryError or NullPointerException will happen.
     // again, not gonna bother tracking this down, but here's a hack.
@@ -96,10 +102,6 @@ public int writePrefix(String program)
       program = substituteUnicode(program);
     }
 
-    //String importRegexp = "(?:^|\\s|;)(import\\s+)(\\S+)(\\s*;)";
-
-    programImports = findIncludes(program);
-
     codeFolderImports = new ArrayList<String>();
 //    if (codeFolderPackages != null) {
 //      for (String item : codeFolderPackages) {
@@ -118,15 +120,16 @@ public int writePrefix(String program)
     return headerCount + prototypeCount;
   }
 
-  public static List<String> findIncludes(String code){
+  public static List<String[]> findIncludes(String code){
    
     String[][] pieces = PApplet.matchAll(code, IMPORT_REGEX);
 
-    ArrayList<String> programImports = new ArrayList<>();
+    ArrayList<String[]> programImports = new ArrayList<>();
     
     if (pieces != null)
       for (int i = 0; i < pieces.length; i++)
-        programImports.add(pieces[i][1]);  // the package name
+        programImports.add(new String[] { pieces[i][1], pieces[i][2] });
+        // the include file name, and the dependency spec (if any)
 
     return programImports;
   }
@@ -208,7 +211,7 @@ protected void writeProgram(PrintStream out, String program, List<String> protot
   protected void writeFooter(PrintStream out) throws java.lang.Exception {}
 
 
-  public List<String> getExtraImports() {
+  public List<String[]> getExtraImports() {
     return programImports;
   }
 

From 99236c2ae65927f01019f55db8898c872339bae1 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 22:29:36 +0100
Subject: [PATCH 11/15] Use | in fallback global name and "" for dep spec.

---
 app/src/processing/app/Sketch.java                        | 2 +-
 arduino-core/src/processing/app/packages/UserLibrary.java | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/app/src/processing/app/Sketch.java b/app/src/processing/app/Sketch.java
index 0f6a5e702f4..2825de43c60 100644
--- a/app/src/processing/app/Sketch.java
+++ b/app/src/processing/app/Sketch.java
@@ -962,7 +962,7 @@ private void importLibrary(File jarPath, String depSpec) throws IOException {
       buffer.append(aList);
       buffer.append(">");
       if (depSpec != null) {
-	buffer.append(" //!Lib '" + depSpec + "'");
+	buffer.append(" //!Lib \"" + depSpec + "\"");
       }
       buffer.append("\n");
     }
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index e15ce109ca9..54a4f257757 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -213,7 +213,7 @@ public void setGlobalName(String gn) {
       invalid = true;
       // Fallback.  Note: the global name is used to test for equality,
       // so it must have a value.
-      globalName = author.replace('/', '_') + "/" + name;
+      globalName = author.replace('|', '_') + "|" + name;
     }
     if (invalid) {
       System.err.println("WARNING: global_name not set in library " + name + ". Guessing '" + globalName + "'.\nPlease set this to a suitable Java-style package name, e.g. io.github.myaccount.myproject\nThe name should be set manually to avoid confusion when forking.");

From 15e106a2746c38624cb03f76336d4ffd4a3a4336 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Thu, 25 Jun 2015 22:52:38 +0100
Subject: [PATCH 12/15] Only use global name for matching, and warn about
 versions.

Version warnings currently only implemented in the case of a direct
import.
---
 .../processing/app/syntax/SketchTextArea.java | 21 ++++++++++++++-----
 .../processing/app/packages/UserLibrary.java  |  9 ++++----
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index b6558795aeb..d1e023203dc 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -41,6 +41,7 @@
 import processing.app.*;
 import processing.app.packages.UserLibrary;
 import processing.app.packages.LibrarySelection;
+import processing.app.preproc.PdePreprocessor;
 
 import javax.swing.*;
 import javax.swing.event.EventListenerList;
@@ -457,19 +458,24 @@ public void mouseMoved(MouseEvent e) {
     }
 
     private String getImportInfo(String line) {
-      LibrarySelection libSel = BaseNoGui.findLibraryByCode(line);
+      java.util.List<String[]> incs = PdePreprocessor.findIncludes(line);
+      LibrarySelection libSel = null;
+      if (!incs.isEmpty()) {
+        libSel = BaseNoGui.findLibraryByImport(incs.get(0));
+      }
       String info = null;
       if (libSel != null) {
         UserLibrary lib = libSel.get();
-        info = getLibDescription(lib);
+        info = getLibDescription(lib, incs.get(0));
         for (LibrarySelection recLibSel : lib.getRequiredLibsRec()) {
-          info += "\n* " + getLibDescription(recLibSel.get());
+          // TODO: also check import spec of recursive deps
+          info += "\n* " + getLibDescription(recLibSel.get(), null);
         }
       }
       return info;
     }
 
-    private String getLibDescription(UserLibrary lib) {
+    private String getLibDescription(UserLibrary lib, String[] importSpec) {
       String ver = lib.getVersion();
       if (ver != null) {
         ver = " " + ver;
@@ -480,7 +486,12 @@ private String getLibDescription(UserLibrary lib) {
       if (lib instanceof UserLibrary) {
         folder = ": " + lib.getSrcFolder().toString();
       }
-      return lib.getName() + " (" + lib.getGlobalName() + ")" + ver + folder;
+      String desc = lib.getName() + " (" + lib.getGlobalName() + ")" + ver + folder;
+      if (importSpec != null && importSpec[1] != null &&
+          !lib.matchesDepSpecVersion(importSpec[1])) {
+        desc += "\nWARNING: "+lib.getGlobalName()+" is an incorrect version.";
+      }
+      return desc;
     }
 
     private void stopScanningForLinks() {
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index 54a4f257757..d8ef4d53137 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -238,10 +238,11 @@ public String getDepSpec() {
 
   public boolean matchesDepSpec(String spec) {
     String[] parts = spec.split(":", 2);
-    if (!getGlobalName().equals(parts[0])) {
-      // Global name does not match - reject.
-      return false;
-    }
+    return getGlobalName().equals(parts[0]);
+  }
+
+  public boolean matchesDepSpecVersion(String spec) {
+    String[] parts = spec.split(":", 2);
     if (parts.length == 1) {
       // No version spec - accept any version.
       return true;

From 8fa7bbd7dd2085d24ff4fec9ce65217631557b1d Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Fri, 26 Jun 2015 11:19:55 +0100
Subject: [PATCH 13/15] Prefer already-directly-imported (or current) library,
 if no descriptor

The tooltips will sometimes get this wrong, unfortunately, as they do not
have enough context.
---
 .../processing/app/syntax/SketchTextArea.java |  3 +-
 .../src/processing/app/BaseNoGui.java         | 30 ++++++++++++++-----
 .../src/processing/app/debug/Compiler.java    |  7 +++--
 .../processing/app/packages/UserLibrary.java  |  8 ++++-
 4 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index d1e023203dc..a8b83feb88b 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -461,7 +461,8 @@ private String getImportInfo(String line) {
       java.util.List<String[]> incs = PdePreprocessor.findIncludes(line);
       LibrarySelection libSel = null;
       if (!incs.isEmpty()) {
-        libSel = BaseNoGui.findLibraryByImport(incs.get(0));
+        // Note: does not have a valid preferSet, so answer may be inaccurate
+        libSel = BaseNoGui.findLibraryByImport(incs.get(0), new HashSet<UserLibrary>());
       }
       String info = null;
       if (libSel != null) {
diff --git a/arduino-core/src/processing/app/BaseNoGui.java b/arduino-core/src/processing/app/BaseNoGui.java
index 8169a10c6ea..76b6b15cf4c 100644
--- a/arduino-core/src/processing/app/BaseNoGui.java
+++ b/arduino-core/src/processing/app/BaseNoGui.java
@@ -964,20 +964,31 @@ static public void populateImportToLibraryTable() {
     }
   }
 
-  static public LibrarySelection findLibraryByImport(String[] importSpec) {
+  static public LibrarySelection findLibraryByImport(String[] importSpec,
+                                                     Set<UserLibrary> preferSet) {
     LibraryList list = importToLibraryTable.get(importSpec[0]);
     if (list == null || list.isEmpty()) {
       return null;
     }
     int index = 0;
-    if (importSpec[1] != null) {
+    if (importSpec[1] != null && !importSpec[1].isEmpty()) {
       for (int i = 0; i < list.size(); i++) {
         if (list.get(i).matchesDepSpec(importSpec[1])) {
           index = i;
         }
       }
+    } else if (preferSet != null) {
+      // No dep spec - prefer library already imported in this context
+      for (int i = 0; i < list.size(); i++) {
+        if (preferSet.contains(list.get(i))) {
+          index = i;
+        }
+      }
     }
-    return new LibrarySelection(list, index);
+    // Keep track of libraries already imported in this context
+    LibrarySelection libSel = new LibrarySelection(list, index);
+    preferSet.add(libSel.get());
+    return libSel;
   }
 
   static public LibrarySelection findLibraryByCode(String code) {
@@ -985,15 +996,16 @@ static public LibrarySelection findLibraryByCode(String code) {
     if (incs.isEmpty()) {
       return null;
     }
-    return findLibraryByImport(incs.get(0));
+    return findLibraryByImport(incs.get(0), null);
   }
 
-  static public List<LibrarySelection> findLibrariesByCode(String code)
+  static public List<LibrarySelection> findLibrariesByCode(String code,
+                                                           Set<UserLibrary> preferSet)
   throws IOException {
     List<LibrarySelection> libs = new ArrayList<>();
     List<String[]> incs = PdePreprocessor.findIncludes(code);
     for (String[] inc : incs) {
-      LibrarySelection lib = findLibraryByImport(inc);
+      LibrarySelection lib = findLibraryByImport(inc, preferSet);
       if (lib != null) {
         libs.add(lib);
       }
@@ -1001,8 +1013,10 @@ static public List<LibrarySelection> findLibrariesByCode(String code)
     return libs;
   }
 
-  static public List<LibrarySelection> findLibrariesByCode(File file) throws IOException {
-    return findLibrariesByCode(FileUtils.readFileToString(file));
+  static public List<LibrarySelection> findLibrariesByCode(File file,
+                                                           Set<UserLibrary> preferSet)
+  throws IOException {
+    return findLibrariesByCode(FileUtils.readFileToString(file), preferSet);
   }
 
   static public void initParameters(String args[]) throws IOException {
diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index 932762a5ced..fce265b0b15 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -623,13 +623,13 @@ static public List<File> findAllSources(File sourcePath, boolean recurse) {
     return allSources;
   }
 
-  static public List<LibrarySelection> findRequiredLibs(File sourcePath, boolean recurse) {
+  static public List<LibrarySelection> findRequiredLibs(File sourcePath, boolean recurse, Set<UserLibrary> preferSet) {
     List<File> files = findAllSources(sourcePath, recurse);
     List<LibrarySelection> result = new ArrayList<>();
     for (File file : files) {
       List<LibrarySelection> libSels = null;
       try { 
-        libSels = BaseNoGui.findLibrariesByCode(file);
+        libSels = BaseNoGui.findLibrariesByCode(file, preferSet);
       } catch (IOException e) {
         continue;
       }
@@ -1389,8 +1389,9 @@ public void preprocess(String buildPath, PdePreprocessor preprocessor) throws Ru
     importedLibraries = new LibraryList();
     importedDuplicateHeaders = new ArrayList<>();
     importedDuplicateLibraries = new ArrayList<>();
+    Set<UserLibrary> preferSet = new HashSet<UserLibrary>();
     for (String[] item : preprocessor.getExtraImports()) {
-      LibrarySelection libSel = BaseNoGui.findLibraryByImport(item);
+      LibrarySelection libSel = BaseNoGui.findLibraryByImport(item, preferSet);
       if (libSel != null) {
         UserLibrary lib = libSel.get();
         if (!importedLibraries.contains(lib)) {
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index d8ef4d53137..caa3c310838 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -44,8 +44,10 @@
 import java.util.List;
 import java.util.TreeMap;
 import java.util.Map;
+import java.util.HashSet;
 import java.util.TreeSet;
 import java.util.SortedSet;
+import java.util.Set;
 
 public class UserLibrary extends ContributedLibrary {
 
@@ -418,7 +420,11 @@ public boolean changedSinceLastUpdateRec(int idx, SortedSet<String> visited) {
 
   public List<LibrarySelection> getRequiredLibs() {
     if (requiredLibs == null || changedSinceLastUpdate(0)) {
-      requiredLibs = Compiler.findRequiredLibs(getSrcFolder(), useRecursion());
+      // Note: the "recursion" in useRecursion() refers to a strategy for
+      // finding files within an individual project
+      Set<UserLibrary> preferSet = new HashSet<>();
+      preferSet.add(this);
+      requiredLibs = Compiler.findRequiredLibs(getSrcFolder(), useRecursion(), preferSet);
       requiredLibs.remove(this);
     }
     return requiredLibs;

From 1454800be0d46128a5c8999cbfb79fb601a182e9 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Fri, 26 Jun 2015 11:44:24 +0100
Subject: [PATCH 14/15] Don't report duplicate libs imported from libs.

---
 arduino-core/src/processing/app/debug/Compiler.java | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index fce265b0b15..bc22f125cb6 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -1404,10 +1404,12 @@ public void preprocess(String buildPath, PdePreprocessor preprocessor) throws Ru
           for (LibrarySelection libSelRec : lib.getRequiredLibsRec()) {
             if (!importedLibraries.contains(libSelRec.get())) {
               importedLibraries.add(libSelRec.get());
-              if (libSelRec.getList().size() > 1) {
-                importedDuplicateHeaders.add("UNKNOWN"); // FIXME
-                importedDuplicateLibraries.add(libSelRec);
-              }
+              // This is probably just confusing. People can examine the
+              // tooltips if they need this information.
+              //if (libSelRec.getList().size() > 1) {
+              //  importedDuplicateHeaders.add("UNKNOWN"); // FIXME
+              //  importedDuplicateLibraries.add(libSelRec);
+              //}
             }
           }
         }

From 200a01233c595efb2eb5b7414c2f301c6daf8f03 Mon Sep 17 00:00:00 2001
From: Martin Sidaway <msidaway@gmail.com>
Date: Fri, 26 Jun 2015 12:05:24 +0100
Subject: [PATCH 15/15] Implement UserLibrary.hashCode() for preferSet.

---
 app/src/processing/app/syntax/SketchTextArea.java         | 2 +-
 arduino-core/src/processing/app/debug/Compiler.java       | 2 +-
 arduino-core/src/processing/app/packages/UserLibrary.java | 7 ++++++-
 3 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/app/src/processing/app/syntax/SketchTextArea.java b/app/src/processing/app/syntax/SketchTextArea.java
index a8b83feb88b..cf362313915 100644
--- a/app/src/processing/app/syntax/SketchTextArea.java
+++ b/app/src/processing/app/syntax/SketchTextArea.java
@@ -462,7 +462,7 @@ private String getImportInfo(String line) {
       LibrarySelection libSel = null;
       if (!incs.isEmpty()) {
         // Note: does not have a valid preferSet, so answer may be inaccurate
-        libSel = BaseNoGui.findLibraryByImport(incs.get(0), new HashSet<UserLibrary>());
+        libSel = BaseNoGui.findLibraryByImport(incs.get(0), new HashSet<>());
       }
       String info = null;
       if (libSel != null) {
diff --git a/arduino-core/src/processing/app/debug/Compiler.java b/arduino-core/src/processing/app/debug/Compiler.java
index bc22f125cb6..b38a3ab0136 100644
--- a/arduino-core/src/processing/app/debug/Compiler.java
+++ b/arduino-core/src/processing/app/debug/Compiler.java
@@ -1389,7 +1389,7 @@ public void preprocess(String buildPath, PdePreprocessor preprocessor) throws Ru
     importedLibraries = new LibraryList();
     importedDuplicateHeaders = new ArrayList<>();
     importedDuplicateLibraries = new ArrayList<>();
-    Set<UserLibrary> preferSet = new HashSet<UserLibrary>();
+    Set<UserLibrary> preferSet = new HashSet<>();
     for (String[] item : preprocessor.getExtraImports()) {
       LibrarySelection libSel = BaseNoGui.findLibraryByImport(item, preferSet);
       if (libSel != null) {
diff --git a/arduino-core/src/processing/app/packages/UserLibrary.java b/arduino-core/src/processing/app/packages/UserLibrary.java
index caa3c310838..f3b8dfce12c 100644
--- a/arduino-core/src/processing/app/packages/UserLibrary.java
+++ b/arduino-core/src/processing/app/packages/UserLibrary.java
@@ -238,6 +238,11 @@ public String getDepSpec() {
     return depSpec;
   }
 
+  @Override
+  public int hashCode() {
+    return getDepSpec().hashCode();
+  }
+
   public boolean matchesDepSpec(String spec) {
     String[] parts = spec.split(":", 2);
     return getGlobalName().equals(parts[0]);
@@ -266,7 +271,7 @@ public boolean matchesDepSpecVersion(String spec) {
     }
   }
 
-  private boolean versionsOrdered(String ver1, String ver2) {
+  static private boolean versionsOrdered(String ver1, String ver2) {
     String[] c1 = ver1.split("\\.");
     String[] c2 = ver2.split("\\.");
     int i;