[8.5.0] Inject repositories after root module file processed

[bazel-io]

This fixes an issue where repositories injected with --inject_repository can invalidate MODULE.bazel.lock by changing the order innate use_repo_rule extensions are registered.

For example;

# //:MODULE.bazel
local_repository = use_repo_rule("@//:defs.bzl", "local_repository")
local_repository(name = "repo")

bazel mod dump_repo_mapping '' --inject_repository=my_repo=%workspace%/other_repo
# Bazel 9+
# {"my_repo":"+local_repository+my_repo","repo":"+local_repository2+repo",...}
# Bazel 8
# {"my_repo":"+_repo_rules+my_repo","repo":"+_repo_rules2+repo",...}

Handling repository injections later changes how collisions with apparent repository names from innate extensions (use_repo_rule(...)(...)) and module extensions (use_extension(...).__(...)) are reported. To permit debugging (and improve collision investigation in general) the error message now refers to the incoming and existing repo name definition.

For example;

-Error in use_repo: The repo name 'my_repo' is already being used by --inject_repository at <builtin>
+ERROR: The repo name 'my_repo' cannot be defined by --inject_repository at <builtin> as it is already defined by a use_repo() call at /___/MODULE.bazel:2:9

Closes #27795.

PiperOrigin-RevId: 841889374
Change-Id: I01a4500ae5580338f96d593323c1d680fdbb7672

Commit d564fc9

[gemini-code-assist]

Summary of Changes

Hello @bazel-io, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request resolves a critical issue where the --inject_repository flag could lead to an invalid MODULE.bazel.lock file by incorrectly altering the order of repository definitions. The core fix involves adjusting the timing of repository injection to happen after the root module file has been processed, ensuring proper resolution. Additionally, the change enhances the clarity of repository name collision error messages, providing more comprehensive information for easier debugging.

Highlights

• Repository Injection Timing: The processing of repositories injected via --inject_repository has been reordered to occur after the root MODULE.bazel file has been fully processed. This change prevents potential invalidation of MODULE.bazel.lock files caused by an incorrect registration order of innate use_repo_rule extensions.
• Enhanced Collision Error Messages: Error messages for repository name collisions have been significantly improved. They now provide more detailed context, explicitly stating both the incoming repository definition and the existing definition that caused the collision, aiding in debugging and investigation.
• New Test Case for Injection Behavior: A new test has been added to specifically verify that --inject_repository does not inadvertently affect repository names generated by use_repo_rule, ensuring the stability and predictability of repository name resolution.

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[gemini-code-assist]

Code Review

This pull request addresses an issue where injected repositories could invalidate MODULE.bazel.lock by altering the registration order of use_repo_rule extensions. The fix correctly defers the injection of repositories until after the root module file has been processed, ensuring a stable registration order. Additionally, the error message for repository name collisions has been significantly improved to provide more context, which will aid in debugging. The changes are well-tested, including a new test case that validates the fix for the lock file invalidation side effect. The implementation is clean and effective. I have one minor suggestion to remove a stray comment in a test file.

[gemini-code-assist]

This line appears to be a stray comment or a leftover from debugging. It should be removed to improve code clarity.

[meteorcloudy]

FYI @Silic0nS0ldier @fmeum

[Silic0nS0ldier]

Thanks for the fixes @fmeum!