Issue 3532. Report error if one unit included twice

compiler/java/com/google/dart/compiler/DartCompiler.java

Index: compiler/java/com/google/dart/compiler/DartCompiler.java
diff --git a/compiler/java/com/google/dart/compiler/DartCompiler.java b/compiler/java/com/google/dart/compiler/DartCompiler.java
index dd85e0b109ce94f4687c1b3210255d64f2e9e1f0..a199884fa04163b915519244ddd57427b3fe83b1 100644
--- a/compiler/java/com/google/dart/compiler/DartCompiler.java
+++ b/compiler/java/com/google/dart/compiler/DartCompiler.java
@@ -619,6 +619,19 @@ public class DartCompiler {
         if (SystemLibraryManager.isDartUri(lib.getSource().getUri())) {
           continue;
         }
+        
+        // check for #source uniqueness
+        {
+          Set<String> includedSourcePaths = Sets.newHashSet();
+          for (LibraryNode sourceNode : lib.getSourcePaths()) {
+            String path = sourceNode.getText();

[Brian Wilkerson, 2012/06/12 15:34:14]

I'm not sure this is correct. Don't we need to catch cases like

  #source('foo.dart');
  #source('../here/foo.dart');

(where 'here' is the directory containing the library file)? I think what we
really need here is

  path = lib.getSource().getSourceFor(sourceNode.getText()).getRelativePath();

[scheglov, 2012/06/12 18:17:51]

Done.

+            if (includedSourcePaths.contains(path)) {
+              context.onError(new DartCompilationError(sourceNode.getSourceInfo(),
+                  DartCompilerErrorCode.UNIT_WAS_ALREADY_INCLUDED, path));
+            }
+            includedSourcePaths.add(path);
+          }
+        }
 
         // check that each imported library has a library directive
         for (LibraryUnit importedLib : lib.getImports()) {
@@ -673,6 +686,7 @@ public class DartCompiler {
                 continue;
               }
               DartSource dartSource = (DartSource) unit.getSourceInfo().getSource();
+              // check for directives
               if (dartSource.getRelativePath().equals(sourceNode.getText())) {
                 context.onError(new DartCompilationError(unit.getDirectives().get(0),
                     DartCompilerErrorCode.ILLEGAL_DIRECTIVES_IN_SOURCED_UNIT,