Remote falls back to local, not sandboxed

[jmmv]

Description of the bug:

We have a few actions that require either remote execution or sandboxed execution: they cannot be built with the local strategy.

We configure Bazel like this:

build --internal_spawn_scheduler
build --spawn_strategy=dynamic
build --remote_local_fallback
build --strategy=BootstrapGNUMake=remote,sandboxed
... some more strategy flags exactly like the previous one ...

But I've noticed that, when a remote action fails due to networking issues, Bazel reruns it without the sandbox and thus the action fails with the local strategy.

I found the --remote_local_fallback_strategy flag, which I thought would resolve our problems... but then this flag is deprecated and its docstring claims that it's a no-op. Then I went to #7480 and, from my understanding of that bug, our strategy flags are already correctly configured. --spawn_strategy says dynamic, and the dynamic scheduler defaults to worker,sandboxed for the local path.

Is there a bug, or is something misconfigured?

Which category does this issue belong to?

Local Execution

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

No response

Which operating system are you running Bazel on?

Linux but this is irrelevant

What is the output of bazel info release?

release 6.5.0

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 HEAD ?

No response

Is this a regression? If yes, please try to identify the Bazel commit where the bug was introduced.

No response

Have you found anything relevant by searching the web?

No response

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

No response

[jmmv]

@tjgq I see you referenced this issue in #19904 but I'm not sure what that means for what I reported here. Is it possible to select "sandboxed" for the local fallback strategy? Or is this currently not doable given that the flag says it's a no-op?

[ulrfa]

Is this a duplicate of #15519?

[jmmv]

Yeah, it looks like it.