Bazel combined cache not working with GCP Storage

[pauldraper]

Description of the bug:

As of 5.2.0, Bazel doesn't download from GCP storage when the disk cache is used.

What's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

WORKSPACE.bazel

BUILD.bazel

genrule(
  name = "example",
  cmd = "date; echo example > $@",
  outs = ["example.txt"],
)

.bazelrc

build --disk_cache=~/.cache/bazel-disk
build --google_default_credentials
build --remote_cache=https://storage.googleapis.com/example-bucket

Build:

bazel build :example

Then clean:

bazel clean
rm -r ~/.cache/bazel-disk/*

Then build again:

bazel build :example

The output for the last step shows: 2 processes: 1 internal, 1 linux-sandbox.

It ought to display: 2 processes: 1 remote cache hit, 1 internal.

Which operating system are you running Bazel on?

Ubuntu 20.04

What is the output of bazel info release?

release 5.2.0

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse master; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

Oddly, this works as expected if I do any one of the following:

1. Remove the --disk_cache option.
2. Use a local HTTP server (nginx) instead of GCP Storage.
3. Use Bazel 5.1.0.

[tjgq]

It appears that this issue was introduced in 4d900ce but later fixed in a24d1bc (and cherry picked into 5.3). As a result, it made it into the 5.2 release, but neither 5.3 nor 6.0 will have the bug; I've confirmed that the provided test case doesn't repro at HEAD, nor in the 5.3 release branch.

[pauldraper]

Excellent!

Now we just need a 5.3.0 release 😅

[pauldraper]

While I can believe that 4d900ce broke it, I am skeptical that a24d1bc fixed it.

[fmeum]

Maybe they meant 4d900ce?

[tjgq]

Sorry, copy paste error. I meant it was fixed by 40e485d (originally #15842).