Bazel cacheing of compilation / test failures?

Question

When compilation succeeds or a test passes, Bazel caches the result so if we repeat the build / test with the exact same code we get the result immediately.

That's great.

However, if the compilation fails - and I repeat the build with the exact same code - Bazel will attempt to recompile the code (and will fail again, with the exact same result)

Same for tests - if a test fails, and I rerun the test with the exact same code - Bazel will repeat the test.

Is there a way to tell Bazel to cache test / compilation failures as well as successes?

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Usecase example:

• I changed a lot of code in multiple files
• I run bazel test //...:all
• 100 tests run, 4 different tests fail
• I fix the code of one of the tests and rerun bazel test //...:all
• All the failing tests run again, even though 3 of the failing tests have no dependency change and there's no point rerunning them
• I have to wait 4x longer than necessary for the tests to finish, and I'm sad :(

Something similar for the build failures. Sometimes a failed build can take many minutes to run on our codebase. If I rebuild without changing the files - it's a waste of time for bazel to rerun the failing build if it can use the cache...

Answer 1

I can see why this might be useful, but I'm not aware of a flag or other option that does something like this. At least in the case of a failing test, Bazel re-runs the failed test even if the inputs haven't changed to account for flaky tests. I suppose the same could be said for actions (a flaky compiler sounds pretty scary though). You might consider filing a feature request: https://github.com/bazelbuild/bazel/issues.

My advice would be to test only the specific target you're working on after running //...:all. You can also combine that with --test_filter to test only a specific test method within the test target.

Answer 2

Partial answer:

If we want to cache test failures, we can add --cache_test_results=yes (as opposed to the default auto which only caches successes). Personally, I've added it to my .bazelrc...

I haven't found a way to cache compilation failures yet, unfortunately...