unused_deps failing with bzlmod

[fzakaria]

I'm failing to run unused_deps on our repository which is migrated to bzlmod.

unused_deps  //apps/cts/lib/metadata/src/test/java/io/confluent/metadata/table/impl/simulator:simulator
2024/12/10 09:31:39 running: bazel query --tool_tag=unused_deps --keep_going --color=yes --curses=yes kind('(kt|java|android)_*', //apps/cts/lib/metadata/src/test/java/io/confluent/metadata/table/impl/simulator:simulator)
2024/12/10 09:31:40 running: bazel build --tool_tag=unused_deps --keep_going --color=yes --curses=yes --output_groups=+unused_deps_outputs --override_repository=unused_deps=/var/folders/4w/cclwgg8s5mxc0g4lbsqkkqdh0000gp/T/unused_deps466578042 --aspects=@unused_deps//:unused_deps.bzl%javac_params //apps/cts/lib/metadata/src/test/java/io/confluent/metadata/table/impl/simulator:simulator
INFO: Invocation ID: 35e165fb-53aa-45cf-aaf6-109b665e85b2
ERROR: Unable to find package for @@[unknown repo 'unused_deps' requested from @@]//:unused_deps.bzl: The repository '@@[unknown repo 'unused_deps' requested from @@]' could not be resolved: No repository visible as '@unused_deps' from main repository.

slack thread

culprit

buildtools/unused_deps/unused_deps.go

Line 383 in 8bd806d

buildCmd = append(buildCmd, "--aspects=@unused_deps//:unused_deps.bzl%javac_params")

This is surprising why it's failing but if I read the documentation for --override_repository on Bazel it says ref:

Note: With Bzlmod, remember to use canonical repo names here. Alternatively, use the --override_module flag to override a module to a local directory, similar to the local_path_override directive in MODULE.bazel.

fix
I applied the following patch and it worked

diff --git a/unused_deps/unused_deps.go b/unused_deps/unused_deps.go
index 6a829c8..ef5d8f4 100644
--- a/unused_deps/unused_deps.go
+++ b/unused_deps/unused_deps.go
@@ -380,7 +380,7 @@ func main() {
 	buildCmd = append(buildCmd, config.DefaultExtraBuildFlags...)
 	buildCmd = append(buildCmd, "--output_groups=+unused_deps_outputs")
 	buildCmd = append(buildCmd, "--override_repository=unused_deps="+aspectDir)
-	buildCmd = append(buildCmd, "--aspects=@unused_deps//:unused_deps.bzl%javac_params")
+	buildCmd = append(buildCmd, "--aspects=@@unused_deps//:unused_deps.bzl%javac_params")
 	buildCmd = append(buildCmd, buildOptions()...)

 	blazeArgs := append(buildCmd, targetPatterns...)