Only allow regular files and directories spawn outputs to be uploaded to a remote cache.

The remote cache protocol only knows about regular files and
directories. Currently, during action output upload, symlinks are
resolved into regular files. This means cached "executions" of an
action may have different output file types than the original
execution, which can be a footgun. This CL bans symlinks from cachable
spawn outputs and fixes https://github.com/bazelbuild/bazel/issues/4840.

The interface of SpawnCache.CacheHandle.store is refactored:
1. The outputs parameter is removed, since that can be retrieved from the underlying Spawn.
2. It can now throw ExecException in order to fail actions.

Closes #4902.

Change-Id: I0d1d94d48779b970bb5d0840c66a14c189ab0091
PiperOrigin-RevId: 190608852

1 files changed, 4 insertions, 2 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/remote/RemoteSpawnCache.java b/src/main/java/com/google/devtools/build/lib/remote/RemoteSpawnCache.java
index 6d766923ab..9b515d16a1 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/RemoteSpawnCache.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/RemoteSpawnCache.java
@@ -160,8 +160,8 @@ final class RemoteSpawnCache implements SpawnCache {
         }
 
         @Override
-        public void store(SpawnResult result, Collection<Path> files)
-            throws InterruptedException, IOException {
+        public void store(SpawnResult result)
+            throws ExecException, InterruptedException, IOException {
           if (options.experimentalGuardAgainstConcurrentChanges) {
             try {
               checkForConcurrentModifications();
@@ -175,6 +175,8 @@ final class RemoteSpawnCache implements SpawnCache {
                   && Status.SUCCESS.equals(result.status())
                   && result.exitCode() == 0;
           Context previous = withMetadata.attach();
+          Collection<Path> files =
+              RemoteSpawnRunner.resolveActionInputs(execRoot, spawn.getOutputFiles());
           try {
             remoteCache.upload(actionKey, execRoot, files, policy.getFileOutErr(), uploadAction);
           } catch (IOException e) {