Switch to RunfilesSuppliers for communicating runfiles

ActionSpawn/SpawnAction now deal exclusively in RunfilesSuppliers, manifests
maps are no more.

There is some lingering awkwardness, in particular:
- Manifests still need to be tracked in some places, we can work out if this is
  still necessary on a case by case basis.
- Skylark makes actions' runfiles available via 'resolve_command' where they are
  consumed by 'action'. I've updated the documentation, though the name isn't
  entirely accurate anymore. That being said these interfaces _are_ marked as
  experimental, so we _should_ be able to be flexible here.

Overall, I think the benefits consolidating runfiles into suppliers, from both
code cleanliness and performance perspectives (no longer needing to parse
manifests), outweights the awkwardnesses.

RELNOTES: resolve_command/action's input_manifest return/parameter is now list

--
PiperOrigin-RevId: 145817429
MOS_MIGRATED_REVID=145817429

1 files changed, 5 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java b/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java
index ff4231f989..7004e29b92 100644
--- a/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java
+++ b/src/main/java/com/google/devtools/build/lib/analysis/SourceManifestAction.java
@@ -107,6 +107,11 @@ public final class SourceManifestAction extends AbstractFileWriteAction {
     this.runfiles = runfiles;
   }
 
+  /** The {@link Runfiles} for which this action creates the symlink tree. */
+  public Runfiles getGeneratedRunfiles() {
+    return runfiles;
+  }
+
   @VisibleForTesting
   public void writeOutputFile(OutputStream out, EventHandler eventHandler)
       throws IOException {