[7.1.0] Avoid exception-based control flow in RemoteActionFileSystem#…

…stat. (#21236)

When statting a file in the local filesystem, we first call
InMemoryFileSystem#stat, which unnecessarily allocates and throws a
FileNotFoundException. Instead, call InMemoryFileSystem#statIfFound,
which doesn't.

PiperOrigin-RevId: 604253151
Change-Id: Iabb9573f710e657a9ea893f1f7577a6b4bb147d2

src/main/java/com/google/devtools/build/lib/remote/RemoteActionFileSystem.java

@@ -605,14 +605,16 @@ private FileStatus statUnchecked(
  }
  }
 
- try {
- return remoteOutputTree.stat(path, /* followSymlinks= */ false);
- } catch (FileNotFoundException e) {
- if (statSources == StatSources.ALL) {
- return localFs.getPath(path).stat(Symlinks.NOFOLLOW);
- }
- throw e;
+ FileStatus stat = remoteOutputTree.statIfFound(path, /* followSymlinks= */ false);
+ if (stat != null) {
+ return stat;
  }
+
+ if (statSources == StatSources.ALL) {
+ return localFs.getPath(path).stat(Symlinks.NOFOLLOW);
+ }
+
+ throw new FileNotFoundException(path.getPathString() + " (No such file or directory)");
  }
 
  private static FileStatusWithMetadata statFromMetadata(FileArtifactValue m) {