Accept proto paths relative to proto_source_root as direct dependencies.

This will make protoc see as direct dependencies the .proto files that were included using the proto_source_root flag.

Until now, Bazel passed to protoc the direct dependencies of a target as the path relative to the WORKSPACE, which made it fail when a shorter path, relative to the package was used.

Progress on #4544.

RELNOTES: None.
PiperOrigin-RevId: 186294997

1 files changed, 46 insertions, 9 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCommon.java b/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCommon.java
index 374b534cd9..2b6f88e2e6 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCommon.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoCommon.java
@@ -100,29 +100,66 @@ public class ProtoCommon {
   }
 
   /**
-   * Returns all proto source roots in this lib and in its transitive dependencies, each prefixed
-   * by {@code --proto_path}.
+   * Returns all proto source roots in this lib ({@code currentProtoSourceRoot}) and in its
+   * transitive dependencies, each prefixed by {@code --proto_path}.
    *
-   * Build will fail if the {@code proto_source_root} of the current lib is different than the
-   * package name.
+   * Assumes {@code currentProtoSourceRoot} is the same as the package name.
    */
-  public static NestedSet<String> collectTransitiveProtoPathFlags(RuleContext ruleContext) {
+  public static NestedSet<String> collectTransitiveProtoPathFlags(
+      RuleContext ruleContext, String currentProtoSourceRoot) {
     NestedSetBuilder<String> protoPathFlags = NestedSetBuilder.stableOrder();
 
     // first add the protoSourceRoot of the current target, if any
+    if (currentProtoSourceRoot != null && !currentProtoSourceRoot.isEmpty()) {
+      protoPathFlags.add("--proto_path=" + currentProtoSourceRoot);
+    }
+
+    for (ProtoSourcesProvider provider : ruleContext.getPrerequisites(
+            "deps", Mode.TARGET, ProtoSourcesProvider.class)) {
+      protoPathFlags.addTransitive(provider.getTransitiveProtoPathFlags());
+    }
+
+    return protoPathFlags.build();
+  }
+
+  /**
+   * Returns the {@code proto_source_root} of the current library or null if none is specified.
+   *
+   * Build will fail if the {@code proto_source_root} of the current library is different than the
+   * package name.
+   */
+  @Nullable
+  public static String getProtoSourceRoot(RuleContext ruleContext) {
     String protoSourceRoot =
         ruleContext.attributes().get("proto_source_root", Type.STRING);
     if (protoSourceRoot != null && !protoSourceRoot.isEmpty()) {
       checkProtoSourceRootIsTheSameAsPackage(protoSourceRoot, ruleContext);
-      protoPathFlags.add("--proto_path=" + protoSourceRoot);
+    }
+    return protoSourceRoot;
+  }
+
+  /**
+   * Returns a set of the {@code proto_source_root} collected from the current library and the
+   * direct dependencies.
+   *
+   * Assumes {@code currentProtoSourceRoot} is the same as the package name.
+   */
+  public static NestedSet<String> getProtoSourceRootsOfDirectDependencies(
+      RuleContext ruleContext, String currentProtoSourceRoot) {
+    NestedSetBuilder<String> protoSourceRoots = NestedSetBuilder.stableOrder();
+    if (currentProtoSourceRoot != null && !currentProtoSourceRoot.isEmpty()) {
+      protoSourceRoots.add(currentProtoSourceRoot);
     }
 
     for (ProtoSourcesProvider provider : ruleContext.getPrerequisites(
-            "deps", Mode.TARGET, ProtoSourcesProvider.class)) {
-      protoPathFlags.addTransitive(provider.getTransitiveProtoPathFlags());
+        "deps", Mode.TARGET, ProtoSourcesProvider.class)) {
+      String protoSourceRoot = provider.getProtoSourceRoot();
+      if (protoSourceRoot != null && !protoSourceRoot.isEmpty()) {
+        protoSourceRoots.add(provider.getProtoSourceRoot());
+      }
     }
 
-    return protoPathFlags.build();
+    return protoSourceRoots.build();
   }
 
   private static void checkProtoSourceRootIsTheSameAsPackage(