Auto merge of #3356 - ibabushkin:feature-build-rustflags, r=alexcrichton

Implemented string lookup for `build.rustflags` config key

This addresses the immediate issue described in #3052 .
I am, however, unsure about the current state of the deeper issues mentioned in that issue, but if needed, I can take stab at them as well. :)

Author: bors

src/cargo/ops/cargo_rustc/context.rs

@@ -889,15 +889,15 @@ fn env_args(config: &Config,
     // Then the target.*.rustflags value
     let target = build_config.requested_target.as_ref().unwrap_or(&build_config.host_triple);
     let key = format!("target.{}.{}", target, name);
-    if let Some(args) = config.get_list(&key)? {
-        let args = args.val.into_iter().map(|a| a.0);
+    if let Some(args) = config.get_list_or_split_string(&key)? {
+        let args = args.val.into_iter();
         return Ok(args.collect());
     }
 
     // Then the build.rustflags value
     let key = format!("build.{}", name);
-    if let Some(args) = config.get_list(&key)? {
-        let args = args.val.into_iter().map(|a| a.0);
+    if let Some(args) = config.get_list_or_split_string(&key)? {
+        let args = args.val.into_iter();
         return Ok(args.collect());
     }
 

src/cargo/util/config.rs

@@ -225,6 +225,36 @@ impl Config {
         }
     }
 
+    pub fn get_list_or_split_string(&self, key: &str)
+                    -> CargoResult<Option<Value<Vec<String>>>> {
+        match self.get_env::<String>(key) {
+            Ok(Some(value)) =>
+                return Ok(Some(Value {
+                    val: value.val.split(' ').map(str::to_string).collect(),
+                    definition: value.definition
+                })),
+            Err(err) => return Err(err),
+            Ok(None) => (),
+        }
+
+        match self.get(key)? {
+            Some(CV::List(i, path)) => {
+                Ok(Some(Value {
+                    val: i.into_iter().map(|(s, _)| s).collect(),
+                    definition: Definition::Path(path),
+                }))
+            }
+            Some(CV::String(i, path)) => {
+                Ok(Some(Value {
+                    val: i.split(' ').map(str::to_string).collect(),
+                    definition: Definition::Path(path),
+                }))
+            }
+            Some(val) => self.expected("list or string", key, val),
+            None => Ok(None),
+        }
+    }
+
     pub fn get_table(&self, key: &str)
                     -> CargoResult<Option<Value<HashMap<String, CV>>>> {
         match self.get(key)? {

tests/rustflags.rs

@@ -949,3 +949,91 @@ fn target_rustflags_precedence() {
     assert_that(p.cargo("bench"),
                 execs().with_status(101));
 }
+
+#[test]
+fn target_rustflags_string_and_array_form1() {
+    let p1 = project("foo")
+        .file("Cargo.toml", r#"
+            [package]
+            name = "foo"
+            version = "0.0.1"
+        "#)
+        .file("src/lib.rs", "")
+        .file(".cargo/config", r#"
+            [build]
+            rustflags = ["--cfg", "foo"]
+            "#);
+    p1.build();
+
+    assert_that(p1.cargo("build").arg("-v"),
+        execs().with_status(0).with_stderr("\
+[COMPILING] foo v0.0.1 ([..])
+[RUNNING] `rustc [..] --cfg foo[..]`
+[FINISHED] debug [unoptimized + debuginfo] target(s) in [..]
+"));
+
+    let p2 = project("foo")
+        .file("Cargo.toml", r#"
+            [package]
+            name = "foo"
+            version = "0.0.1"
+        "#)
+        .file("src/lib.rs", "")
+        .file(".cargo/config", r#"
+            [build]
+            rustflags = "--cfg foo"
+            "#);
+    p2.build();
+
+    assert_that(p2.cargo("build").arg("-v"),
+        execs().with_status(0).with_stderr("\
+[COMPILING] foo v0.0.1 ([..])
+[RUNNING] `rustc [..] --cfg foo[..]`
+[FINISHED] debug [unoptimized + debuginfo] target(s) in [..]
+"));
+
+}
+
+#[test]
+fn target_rustflags_string_and_array_form2() {
+    let p1 = project("foo")
+        .file("Cargo.toml", r#"
+            [package]
+            name = "foo"
+            version = "0.0.1"
+        "#)
+        .file(".cargo/config", &format!(r#"
+            [target.{}]
+            rustflags = ["--cfg", "foo"]
+        "#, rustc_host()))
+        .file("src/lib.rs", "");
+    p1.build();
+
+    assert_that(p1.cargo("build").arg("-v"),
+        execs().with_status(0).with_stderr("\
+[COMPILING] foo v0.0.1 ([..])
+[RUNNING] `rustc [..] --cfg foo[..]`
+[FINISHED] debug [unoptimized + debuginfo] target(s) in [..]
+"));
+
+    let p2 = project("foo")
+        .file("Cargo.toml", r#"
+            [package]
+            name = "foo"
+            version = "0.0.1"
+        "#)
+        .file(".cargo/config", &format!(r#"
+            [target.{}]
+            rustflags = "--cfg foo"
+        "#, rustc_host()))
+        .file("src/lib.rs", "");
+    p2.build();
+
+    assert_that(p2.cargo("build").arg("-v"),
+        execs().with_status(0).with_stderr("\
+[COMPILING] foo v0.0.1 ([..])
+[RUNNING] `rustc [..] --cfg foo[..]`
+[FINISHED] debug [unoptimized + debuginfo] target(s) in [..]
+"));
+
+}