Recommend using --verbose_failures for debugging
See this question on Stack Overflow: https://stackoverflow.com/questions/62456527/how-to-debug-remote-cache-write-failures
I just had an issue with Bazel where I gave my service account rights to read and write in my GCS bucket, but I did not give it blob admin rights, and Bazel tried to do a delete, which failed with this exception:
```
WARNING: Writing to Remote Cache:
com.google.devtools.build.lib.remote.BulkTransferException
at com.google.devtools.build.lib.remote.RemoteCache.waitForBulkTransfer(RemoteCache.java:225)
...
Suppressed: com.google.devtools.build.lib.remote.http.HttpException: 403 Forbidden
```
However, [the way the error message is created](https://github.com/bazelbuild/bazel/blob/9cc17b52abc6e05212843a9c167553b410528982/src/main/java/com/google/devtools/build/lib/remote/RemoteSpawnCache.java#L307) made it only display like this without `--verbose_failures`:
```
WARNING: Writing to Remote Cache:
BulkTransferException
```
This was a very generic error, and I did not find anything online telling me how to get a better error message. Only reading the source tipped me off to the option of using `--verbose_failures`.
I might also later send a PR updating `RemoteSpawnCache` to fix the error message to add something like `Pass --verbose_failures for full backtrace` if called without `--verbose_failures`.
Closes #12945.
PiperOrigin-RevId: 387342220
diff --git a/site/docs/remote-caching-debug.md b/site/docs/remote-caching-debug.md
index e1e8d36..4b89be7 100644
--- a/site/docs/remote-caching-debug.md
+++ b/site/docs/remote-caching-debug.md
@@ -54,7 +54,9 @@
Such warnings will be followed by the error message detailing the connection
problem that should help you debug: for example, mistyped endpoint name or
- incorrectly set credentials. Find and address any such errors.
+ incorrectly set credentials. Find and address any such errors. If the error
+ message you see does not give you enough information, try adding
+ `--verbose_failures`.
2. Follow the steps from [Troubleshooting cache hits for remote
execution](/remote-execution-caching-debug.html#troubleshooting-cache-hits) to
