Error ranges in the editor

compiler.go

@@ -135,17 +135,17 @@ func (job compilerJob) Run() error {
 	env := []string{"GOPROXY=off"} // don't download dependencies
 	switch job.Compiler {
 	case "go":
-		cmd = exec.Command("go", "build", "-trimpath", "-ldflags", "-s -w", "-o", tmpfile, infile.Name())
+		cmd = exec.Command("go", "build", "-json", "-trimpath", "-ldflags", "-s -w", "-o", tmpfile, infile.Name())
 		env = append(env, "GOOS=wasip1", "GOARCH=wasm")
 	case "tinygo":
 		switch job.Format {
 		case "wasm", "wasi":
 			// simulate
 			tag := strings.Replace(job.Target, "-", "_", -1) // '-' not allowed in tags, use '_' instead
-			cmd = exec.Command("tinygo", "build", "-o", tmpfile, "-target", job.Format, "-tags", tag, "-no-debug", infile.Name())
+			cmd = exec.Command("tinygo", "build", "-json", "-o", tmpfile, "-target", job.Format, "-tags", tag, "-no-debug", infile.Name())
 		default:
 			// build firmware
-			cmd = exec.Command("tinygo", "build", "-o", tmpfile, "-target", job.Target, infile.Name())
+			cmd = exec.Command("tinygo", "build", "-json", "-o", tmpfile, "-target", job.Target, infile.Name())
 		}
 	}
 	buf := &bytes.Buffer{}

editor/editor.js

@@ -184,6 +184,9 @@ export class Editor {
         if (diag.col <= 0) {
           from = index;
           to   = index + line.length;
+        } else if (diag.col2 > 0) {
+          // There is a separate end position for this diagnostic.
+          to = index + diag.col2 - 1;
         }
         result.push({
           from: from,

simulator.js

@@ -510,10 +510,11 @@ class Simulator {
     } else if (msg.type == 'error') {
       // There was an error. Terminate the worker, it has no more work to do.
       this.#stopWorker();
-      this.terminal.appendError(msg.message);
+      let [output, diagnostics] = parseCompilerErrors(msg.message);
+      this.terminal.appendError(output);
       if (msg.source === 'compiler') {
         if (this.editor) {
-          this.editor.setDiagnostics(parseCompilerErrors(msg.message));
+          this.editor.setDiagnostics(diagnostics);
         }
       }
     } else if (msg.type === 'stdout') {
@@ -2006,22 +2007,58 @@ function parseUnitMM(value) {
 // Parse compiler errors from the Go (or TinyGo) compiler and convert them to an
 // array of diagnostics ready to give to the editor.
 function parseCompilerErrors(message) {
+  let output = '';
   let diagnostics = [];
-  let re = new RegExp("^main\.go:([0-9]+)(:([0-9]+))?: (.*)$")
+  let messageRegExp = new RegExp("^main\.go:([0-9]+)(:([0-9]+))?: (.*)\n$")
+  let posRegExp = new RegExp("^main\.go:([0-9]+)(:([0-9]+))?$")
   let lines = message.split('\n');
   for (let line of lines) {
-    let result = re.exec(line);
+    if (line === '') continue;
+
+    // Parse JSON build output.
+    if (!line.startsWith('{')) {
+      console.warn('non-JSON compiler error:', line);
+      output += line + '\n';
+      continue;
+    }
+    let data;
+    try {
+      data = JSON.parse(line);
+    } catch (e) {
+      console.warn('failed to parse JSON compiler error:', line);
+      output += line + '\n';
+      continue;
+    }
+    if (data.Action !== 'build-output') {
+      continue;
+    }
+
+    // Parse error message.
+    output += data.Output;
+    let result = messageRegExp.exec(data.Output);
     if (result === null) {
       continue;
     }
-    diagnostics.push({
+
+    // Create the diagnostic to be sent to the editor.
+    let diagnostic = {
       line: parseInt(result[1]),
       col: result[3] ? parseInt(result[3]) : 0,
       severity: 'error',
       message: result[4],
-    })
+    };
+    diagnostics.push(diagnostic)
+
+    // Check whether there is an end position, for slightly better (IDE-like)
+    // inline error messages.
+    let endPosParsed = posRegExp.exec(data.EndPos);
+    if (endPosParsed !== null) {
+      if (parseInt(endPosParsed[1]) === diagnostic.line) {
+        diagnostic.col2 = parseInt(endPosParsed[3]);
+      }
+    }
   }
-  return diagnostics;
+  return [output, diagnostics];
 }
 
 // Upgrade state object if the configuration is of an older type.