Fixing #3380: output stack traces and informative messages.

Also added tests specifically for the output, to ensure we don't break it again.

TESTED=remote worker, unit tests
RELNOTES: fixes #3380
PiperOrigin-RevId: 163283558

1 files changed, 3 insertions, 6 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/remote/CacheNotFoundException.java b/src/main/java/com/google/devtools/build/lib/remote/CacheNotFoundException.java
index cffc58fd4b..15ff3ef3ad 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/CacheNotFoundException.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/CacheNotFoundException.java
@@ -15,24 +15,21 @@
 package com.google.devtools.build.lib.remote;
 
 import com.google.devtools.remoteexecution.v1test.Digest;
+import java.io.IOException;
 
 /**
  * An exception to indicate cache misses.
  * TODO(olaola): have a class of checked RemoteCacheExceptions.
  */
-public final class CacheNotFoundException extends Exception {
+public final class CacheNotFoundException extends IOException {
   private final Digest missingDigest;
 
   CacheNotFoundException(Digest missingDigest) {
+    super("Missing digest: " + missingDigest);
     this.missingDigest = missingDigest;
   }
 
   public Digest getMissingDigest() {
     return missingDigest;
   }
-
-  @Override
-  public String toString() {
-    return "Missing digest: " + missingDigest;
-  }
 }