fineGrainedHashExternalRepos parameter issue

[lukasmi93]

Hi,

I noticed some issue with bazel-diff in my local setup. I use bazel 8.1.0 and bazel-diff 9.0.0
If I use bazel-diff with parameter "--fineGrainedHashExternalRepos @rules_cc", I get the error:

ERROR: error loading package under directory '': error loading package '@@rules_cc+//tests/system_library': Unable to find package for @@[unknown repo 'rules_shell' requested from @@rules_cc+]//shell:sh_test.bzl: The repository '@@[unknown repo 'rules_shell' requested from @@rules_cc+]' could not be resolved: No repository visible as '@rules_shell' from repository '@@rules_cc+'.

It's probably related to this issue: https://stackoverflow.com/questions/79374099/bazel-8-no-such-package-unknown-repo-platforms-requested-from-os
I added "rules_shell" directly to my MODULE.bazel but no success:

bazel_dep(name = "rules_shell", version = "0.2.0")

MODULE.bazel file content:

module(
    name = "my-module",
    version = "0.0.1",
)

bazel_dep(name = "rules_cc", version = "0.1.1")
# bazel_dep(name = "rules_shell", version = "0.2.0")

http_jar = use_repo_rule("@bazel_tools//tools/build_defs/repo:http.bzl", "http_jar")

http_jar(
    name = "bazel_diff",
    sha256 = "5f36e74a8d6167e4d31f663526a63be3e3728456d8b5b4a84503315dd10e65e7",
    urls = [
        "https://github.com/Tinder/bazel-diff/releases/download/9.0.0/bazel-diff_deploy.jar",
    ],
)

Root BUILD file:

java_binary(
    name = "bazel-diff",
    main_class = "com.bazel_diff.Main",
    runtime_deps = ["@bazel_diff//jar"],
)

Bazel-diff command:

bazel run --verbose_failures :bazel-diff -- generate-hashes --keep_going --fineGrainedHashExternalRepos @rules_cc --workspacePath=<workspace-dir> "/tmp/hashes.json"

Any advice appreciated.

[romanoid]

Ran across this just now.

I'm debugging a similar problem, unless I'm misinterpreting the code, --keep_going is effectively ignored (it still makes bazel to do the full query, but fails regardless) due to the exit code being honored here:

bazel-diff/cli/src/main/kotlin/com/bazel_diff/bazel/BazelQueryService.kt

Lines 154 to 155 in 41c5bc2

	if (result.resultCode != 0)
	throw RuntimeException("Bazel query failed, exit code ${result.resultCode}")

I don't think simply removing that check is backwards compatible change, so maybe worth adding default false --allow_failures to be a new opt in to allow query to fail (likely to happen in a lot of external repos due to how bzlmod is usually set up)

Will wait for opinions of maintainers.

[tinder-maxwellelliott]

@romanoid Shouldn't --keep_going just allow failure here regardless? I am not sure if we need an additional flag

[romanoid-openai]

@tinder-maxwellelliott Agree, I was overthinking it (people relying on keep going to get all the errors but still wanting to fail, we do something similar in the ci), but that use case is unlikely to apply to selection

[lukasmi93]

--keep_going doesn't work for my case.
I don't know the root cause of my error.

Any advice appreciated.

[tinder-maxwellelliott]

--keep_going doesn't work for my case. I don't know the root cause of my error.

Any advice appreciated.

What kind of error are you seeing when using keep_going?

[romanoid]

@tinder-maxwellelliott if you look at my post above, I linked to the code that fails:

bazel-diff/cli/src/main/kotlin/com/bazel_diff/bazel/BazelQueryService.kt

Lines 154 to 155 in 41c5bc2

	if (result.resultCode != 0)
	throw RuntimeException("Bazel query failed, exit code ${result.resultCode}")

In short: bazel's behavior for keep going is to continue running instead of stopping at first failure, but the eventual exit code is still non-0.

This causes bazel diff to raise based on exit code.

Sorry for being too brief above, when I said keep-going to be sufficient I meant bazel-diff can just use it's keep going flag to not raise on non-0 exit code if the flag is set (in addition to passing the flag to bazel, which it already does)

[lukasmi93]

I checked the changes on the branch and it didn't solve my issue.
Even after skipping the Bazel query errors, I see that an empty JSON output file is being created.
This means that my error is critical for bazel-diff to work correctly.

I'll go back to my original problem.
Do you know if and how the external repositories/dependency in the MODULE.bazel file are supported by bazel-diff?
For example, if we change the version of an external repository/dependency in the MODULE.bazel file, how do we make bazel-diff find all impacted targets in the current repository that use this external, changed repository/dependency?
Perhaps the flag I'm using, --fineGrainedHashExternalRepos, isn't intended for this purpose?