only filters labels according to parent packages for LanguageClass.C (#…

…47)

* only filters labels according to parent packages for LanguageClass.C
This is to keep supporting CPP need while also supporting aggregate targets
More info:
https://bazelbuild.slack.com/archives/CM8JQCANN/p1566481600003600
Filter was deliberately added to fix an issue with C++ headers.
The original bug was that opening the BUILD file for foo/bar.h caused it to open baz/qux/BUILD because there’s a cc_library target in baz/qux that includes foo/bar.h in its headers. The source-to-target look up queries the index for the target during the last sync which compiled the source file. In this case, it was the cc_library target in baz/qux.
So the fix was to ensure that the BUILD file is always for the parent package (foo/bar)

base/src/com/google/idea/blaze/base/actions/BuildFileUtils.java

@@ -25,18 +25,21 @@
 import com.google.idea.blaze.base.lang.buildfile.search.BlazePackage;
 import com.google.idea.blaze.base.model.BlazeProjectData;
 import com.google.idea.blaze.base.model.primitives.Label;
+import com.google.idea.blaze.base.model.primitives.LanguageClass;
 import com.google.idea.blaze.base.model.primitives.WorkspacePath;
 import com.google.idea.blaze.base.sync.data.BlazeProjectDataManager;
 import com.google.idea.blaze.base.targetmaps.SourceToTargetMap;
 import com.google.idea.common.experiments.BoolExperiment;
 import com.intellij.openapi.project.Project;
+import com.intellij.openapi.util.io.FileUtilRt;
 import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.psi.PsiElement;
 import com.intellij.psi.PsiFileSystemItem;
 import com.intellij.psi.PsiManager;
 import java.io.File;
 import java.util.Arrays;
 import java.util.Set;
+import java.util.stream.Stream;
 import javax.annotation.Nullable;
 
 /** BUILD-file utility methods used by actions. */
@@ -74,9 +77,11 @@ static PsiElement findBuildTarget(Project project, BlazePackage parentPackage, F
     if (packagePath == null) {
       return null;
     }
+    final Stream<Label> targetLabels = SourceToTargetMap.getInstance(project)
+        .getTargetsToBuildForSourceFile(file).stream();
+
     Label label =
-        SourceToTargetMap.getInstance(project).getTargetsToBuildForSourceFile(file).stream()
-            .filter(l -> l.blazePackage().equals(packagePath))
+        filterCRelatedLabelsWhichBelongToOtherPackages(file,packagePath, targetLabels)
             .findFirst()
             .orElse(null);
     if (label == null) {
@@ -98,6 +103,28 @@ static PsiElement findBuildTarget(Project project, BlazePackage parentPackage, F
     return null;
   }
 
+  private static Stream<Label> filterCRelatedLabelsWhichBelongToOtherPackages(File file,
+      WorkspacePath packagePath, Stream<Label> targetLabels) {
+    /*
+      More info:
+      https://bazelbuild.slack.com/archives/CM8JQCANN/p1566481600003600
+      Filter was deliberately added to fix an issue with C++ headers.
+      The original bug was that opening the BUILD file for foo/bar.h caused it to open baz/qux/BUILD
+      because there’s a cc_library target in baz/qux that includes foo/bar.h in its headers.
+      The source-to-target look up queries the index for the target during the last sync which compiled the source file.
+      In this case, it was the cc_library target in baz/qux.
+      So the fix was to ensure that the BUILD file is always for the parent package (foo/bar).
+
+      This is limited to C only since this logic messes up supporting aggregate targets
+      https://github.com/bazelbuild/intellij/issues/475
+     */
+    LanguageClass fileLanguage = LanguageClass.fromExtension(
+        FileUtilRt.getExtension(file.getName()).toLowerCase());
+    return (fileLanguage == LanguageClass.C) ?
+            targetLabels.filter(l -> l.blazePackage().equals(packagePath)) :
+            targetLabels;
+  }
+
   /**
    * Returns the label of a macro with name prefixing the target name of a given label with a '_' or
    * '-' delimiter.