Link to tools/objc/dummy.c from output directory to allow xcodeproj to resolve the file even while outside a workspace which contains it

--
MOS_MIGRATED_REVID=101462428

3 files changed, 37 insertions, 4 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java b/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java
index 754adc96fd..5c46270b1f 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/IntermediateArtifacts.java
@@ -17,6 +17,7 @@ package com.google.devtools.build.lib.rules.objc;
 import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.syntax.Label;
 import com.google.devtools.build.lib.vfs.FileSystemUtils;
@@ -74,6 +75,15 @@ final class IntermediateArtifacts {
   }
 
   /**
+   * A dummy .c file to be included in xcode projects. This is needed if the target does not have
+   * any source files but Xcode requires one.
+   */
+  public Artifact dummySource() {
+    return scopedArtifact(
+        ruleContext.getPrerequisiteArtifact("$dummy_source", Mode.TARGET).getRootRelativePath());
+  }
+
+  /**
    * The output of using {@code actoolzip} to run {@code actool} for a given bundle which is
    * merged under the {@code .app} or {@code .bundle} directory root.
    */
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeProvider.java b/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeProvider.java
index 3e77023af2..a7860d6bab 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeProvider.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeProvider.java
@@ -331,11 +331,14 @@ public final class XcodeProvider implements TransitiveInfoProvider {
    */
   public static final class Project {
     private final NestedSet<Artifact> inputsToXcodegen;
+    private final NestedSet<Artifact> additionalSources;
     private final ImmutableList<XcodeProvider> topLevelTargets;
 
     private Project(
-        NestedSet<Artifact> inputsToXcodegen, ImmutableList<XcodeProvider> topLevelTargets) {
+        NestedSet<Artifact> inputsToXcodegen, NestedSet<Artifact> additionalSources,
+        ImmutableList<XcodeProvider> topLevelTargets) {
       this.inputsToXcodegen = inputsToXcodegen;
+      this.additionalSources = additionalSources;
       this.topLevelTargets = topLevelTargets;
     }
 
@@ -345,10 +348,13 @@ public final class XcodeProvider implements TransitiveInfoProvider {
 
     public static Project fromTopLevelTargets(Iterable<XcodeProvider> topLevelTargets) {
       NestedSetBuilder<Artifact> inputsToXcodegen = NestedSetBuilder.stableOrder();
+      NestedSetBuilder<Artifact> additionalSources = NestedSetBuilder.stableOrder();
       for (XcodeProvider target : topLevelTargets) {
         inputsToXcodegen.addTransitive(target.inputsToXcodegen);
+        additionalSources.addTransitive(target.additionalSources);
       }
-      return new Project(inputsToXcodegen.build(), ImmutableList.copyOf(topLevelTargets));
+      return new Project(inputsToXcodegen.build(), additionalSources.build(),
+          ImmutableList.copyOf(topLevelTargets));
     }
 
     /**
@@ -358,6 +364,13 @@ public final class XcodeProvider implements TransitiveInfoProvider {
     public NestedSet<Artifact> getInputsToXcodegen() {
       return inputsToXcodegen;
     }
+    
+    /**
+     * Returns artifacts that are additional sources for the Xcodegen action.
+     */
+    public NestedSet<Artifact> getAdditionalSources() {
+      return additionalSources;
+    }
 
     /**
      * Returns all the target controls that must be added to the xcodegen control. No other target
diff --git a/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeSupport.java b/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeSupport.java
index 0f390ad421..45f9726009 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeSupport.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/objc/XcodeSupport.java
@@ -24,6 +24,7 @@ import com.google.devtools.build.lib.analysis.RuleConfiguredTarget.Mode;
 import com.google.devtools.build.lib.analysis.RuleContext;
 import com.google.devtools.build.lib.analysis.actions.BinaryFileWriteAction;
 import com.google.devtools.build.lib.analysis.actions.SpawnAction;
+import com.google.devtools.build.lib.analysis.actions.SymlinkAction;
 import com.google.devtools.build.lib.collect.nestedset.NestedSetBuilder;
 import com.google.devtools.build.lib.packages.ImplicitOutputsFunction.SafeImplicitOutputsFunction;
 import com.google.devtools.build.lib.rules.objc.ReleaseBundlingSupport.SplitArchTransition.ConfigurationDistinguisher;
@@ -75,8 +76,16 @@ public final class XcodeSupport {
    * @return this xcode support
    */
   XcodeSupport addDummySource(XcodeProvider.Builder xcodeProviderBuilder) {
-    xcodeProviderBuilder.addAdditionalSources(
-        ruleContext.getPrerequisiteArtifact("$dummy_source", Mode.TARGET));
+    IntermediateArtifacts intermediateArtifacts =
+        ObjcRuleClasses.intermediateArtifacts(ruleContext);
+
+    ruleContext.registerAction(new SymlinkAction(
+        ruleContext.getActionOwner(),
+        ruleContext.getPrerequisiteArtifact("$dummy_source", Mode.TARGET),
+        intermediateArtifacts.dummySource(),
+        "Symlinking dummy artifact"));
+
+    xcodeProviderBuilder.addAdditionalSources(intermediateArtifacts.dummySource());
     return this;
   }
 
@@ -207,6 +216,7 @@ public final class XcodeSupport {
         .addInputArgument(controlFile)
         .addOutput(ruleContext.getImplicitOutputArtifact(XcodeSupport.PBXPROJ))
         .addTransitiveInputs(project.getInputsToXcodegen())
+        .addTransitiveInputs(project.getAdditionalSources())
         .build(ruleContext));
   }