Backport #12069: Add project monitoring logging

[mergify]

Split from #11884. Adds project file monitoring logging at the info level with tests. Logging at the info level is not marked so what I do for the tests is export and use mkNormalizerEnv for normalized comparisons.

Important

Removes the assertion "stanzas explicitly disabled should not be available", see #12067 and #11568.

I'll squash commits before applying the merge label if this pull request is approved.

Manual QA

This command will surface the monitoring:

$ cabal run cabal-install -- build all --dry-run \
  --project-dir=cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/ -v2
...
Monitor existing:
/home/.../cabal/cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project
Monitor imported: cabal.project
(/home/.../cabal/cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project)
Monitor imported: cabal.project
(/home/.../cabal/cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project)
Monitor imported: cabal.project
(/home/.../cabal/cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project)
Monitor nonexistent:
/home/.../cabal/cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project.freeze
Monitor nonexistent:
/home/.../cabal/cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project.local

Note

The root cabal.project is logged as being monitored multiple times. Showing the root of the import path not the leaf as "Monitor imported: cabal.project" is a bug. I have a one-line fix for this problem, included and to be applied in a separate pull request, #11884.

---

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---

This is an automatic backport of pull request #12069 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of ffc9edd has failed:

On branch mergify/bp/3.18/pr-12069
Your branch is up to date with 'origin/3.18'.

You are currently cherry-picking commit ffc9edd42.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   cabal-install/src/Distribution/Client/ProjectPlanning.hs
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/app/Main.hs
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal-project-repro.cabal
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.freeze-only.actual.txt
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.freeze-only.expect.txt
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.freeze-only.project
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.freeze-only.project.freeze
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.local-only.actual.txt
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.local-only.expect.txt
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.local-only.project
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.local-only.project.local
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.main-project.actual.txt
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.main-project.expect.txt
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.project
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/cabal.test.hs
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/nested/deeply-nested/hop.config
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/nested/hop.config
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/test/Main.hs
	new file:   cabal-testsuite/PackageTests/ProjectImport/FileMonitoring/test/tests-toggle.config
	modified:   cabal-testsuite/src/Test/Cabal/Monad.hs
	new file:   changelog.d/12069.md

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   cabal-install/src/Distribution/Client/ProjectConfig.hs

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[Mikolaj]

@philderbeast: any idea what's missing to backport cleanly?

[philderbeast]

There's a merge conflict. Can I add a commit to fix those and remove the <<<<<<< and >>>>>>> markers?

$ grep -E "<<<<<|>>>>>" cabal-install/src/Distribution/Client/ProjectConfig.hs
<<<<<<< HEAD
>>>>>>> ffc9edd42 (Add project monitoring test)
<<<<<<< HEAD
>>>>>>> ffc9edd42 (Add project monitoring test)

[Mikolaj]

@philderbeast: yes, please kindly take over this backport.

[philderbeast]

@Mikolaj I think we need to backport #11995 too. Shall I go ahead and do that?

[Mikolaj]

Aha! Yes, please do that.

[philderbeast]

I'll close this one and try again with a fresh backport request.

[philderbeast]

Mergify doesn't create a new pull request but tries this one again. I'll fix the branch.

[philderbeast]

@Mikolaj this one is ready for review.

[Mikolaj]

LGTM. Thank you.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-07-04 20:44 UTC · Rule: default · triggered by rule Put backports in the rebase+merge queue
• ✅ Checks skipped · PR is already up-to-date
• ✅ Merged — 2026-07-04 20:55 UTC · at 9afc173e6b700db798fe23349c8a4134e1ea102c · merge

This pull request spent 10 minutes 37 seconds in the queue, including 1 second running CI.

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