Show import tree provenance (backport #9578)

[mergify]

Fixes #9562. This adds the path in the project import tree with the constraint conflict just below the solver's rejecting message (sample taken from the change log entry).

$ cabal build all --dry-run
...
[__1] next goal: hashable
[__1] rejecting: hashable-1.4.3.0
      (<ROOT>/1-web-import-constraints.project requires ==1.4.2.0)
[__1] rejecting: hashable-1.4.2.0
      (https://www.stackage.org/nightly-2023-12-07/cabal.config requires ==1.4.3.0)
        imported by: <ROOT>/1-web-import-constraints.project

Important

The way imports worked changed between cabal-install-3.8 and cabal-install-3.10. With the earlier version imports were anchored to the project root (relative to a fixed location) but this was changed to make them relative to their importer. I had to pay close attention to the check for seen imports, something I added tests for. These tests merged already with #9665 and #9680. I've also added verbose logging at the info level so we can see the import we're processing, the seen imports and the import we're fetching.

Because relative imports may contain .. and the only way to resolve this is to use canonicalizePath I had to take an extra dependency on directory in cabal-install-solver. I also needed network-uri to check for URIs and avoid messing with them. I assume that once we import a URI config then imports stop there. Put another way, something imported via https://... doesn't itself import another config. Those extra dependencies we should be able to remove when the suggested change of @andreabedini lands, #9642.

• Patches conform to the coding conventions.
• Any changes that could be relevant to users have been recorded in the changelog.
• The documentation has been updated, if necessary. (Can't find "rejecting" in the docs to change).
• Manual QA notes have been included.
• Tests have been added. (I took stripped down tests that I hope to reuse and expand for Override imported package version equalities #9510).

If testing manually, I suggest trying cabal build --dry-run with a simple cabal.project, a project with imports and a bare package with no project. To see the change, a solver rejection will need to be triggered by introducing a version constraint.

Note

I'd tried to use a tree-like layout but settled on a list instead after review.

I used +-- ASCII chars to mark tree nodes (and not the same ones as tree does). Can we use the nicer unicode chars?

$ tree -P 'cabal.project*' --prune -L 1 --charset ascii
.
|-- cabal.project
|-- cabal.project.buildinfo
|-- cabal.project.coverage
|-- cabal.project.doctest
|-- cabal.project.latest-ghc
|-- cabal.project.libonly
|-- cabal.project.meta
|-- cabal.project.release
|-- cabal.project.validate
|-- cabal.project.validate.libonly
`-- cabal.project.weeder

$ tree -P 'cabal.project*' --prune -L 1 --charset utf8
.
├── cabal.project
├── cabal.project.buildinfo
├── cabal.project.coverage
├── cabal.project.doctest
├── cabal.project.latest-ghc
├── cabal.project.libonly
├── cabal.project.meta
├── cabal.project.release
├── cabal.project.validate
├── cabal.project.validate.libonly
└── cabal.project.weeder
```<hr>This is an automatic backport of pull request #9578 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of f8cd563 has failed:

On branch mergify/bp/3.12/pr-9578
Your branch is up to date with 'origin/3.12'.

You are currently cherry-picking commit f8cd56341.
  (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-solver/cabal-install-solver.cabal
	modified:   cabal-install-solver/src/Distribution/Solver/Modular/Message.hs
	modified:   cabal-install-solver/src/Distribution/Solver/Types/ConstraintSource.hs
	new file:   cabal-install-solver/src/Distribution/Solver/Types/ProjectConfigPath.hs
	modified:   cabal-install/src/Distribution/Client/ProjectConfig.hs
	modified:   cabal-install/src/Distribution/Client/ProjectConfig/Types.hs
	modified:   cabal-install/src/Distribution/Client/ProjectPlanning.hs
	modified:   cabal-install/src/Distribution/Client/ScriptUtils.hs
	modified:   cabal-install/tests/UnitTests/Distribution/Client/ProjectConfig.hs
	modified:   cabal-install/tests/UnitTests/Distribution/Client/TreeDiffInstances.hs
	modified:   cabal-testsuite/PackageTests/ConditionalAndImport/cabal.out
	modified:   cabal-testsuite/PackageTests/ConditionalAndImport/cabal.test.hs
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops-0.project
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops-2.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops-4.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops-6.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops-8.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops/oops-1.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops/oops-3.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops/oops-5.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops/oops-7.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops/oops-9.config
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/oops/oops.cabal
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/repo/hashable-1.4.2.0/hashable.cabal
	new file:   cabal-testsuite/PackageTests/ConditionalAndImport/repo/hashable-1.4.3.0/hashable.cabal
	modified:   cabal-testsuite/PackageTests/ConditionalAndImport/same-filename/noncyclical-same-filename-b.config
	modified:   cabal-testsuite/PackageTests/VersionPriority/0-local.out
	modified:   cabal-testsuite/PackageTests/VersionPriority/1-local.out
	modified:   cabal-testsuite/PackageTests/VersionPriority/1-web.out
	modified:   cabal-testsuite/PackageTests/VersionPriority/2-local.out
	modified:   cabal-testsuite/PackageTests/VersionPriority/2-web.out
	modified:   cabal-testsuite/PackageTests/VersionPriority/3-web.out
	modified:   cabal-testsuite/PackageTests/VersionPriority/repo/hashable-1.4.2.0/hashable.cabal
	modified:   cabal-testsuite/PackageTests/VersionPriority/repo/hashable-1.4.3.0/hashable.cabal
	new file:   changelog.d/issue-9578

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

[geekosaur]

Backports don't accept "squash+merge me" (https://github.com/haskell/cabal/blob/master/.github/mergify.yml#L59-L72). I was hoping the "fixup!" prefixes would get the additional commits squashed (https://git-scm.com/docs/git-commit#Documentation/git-commit.txt---fixupamendrewordltcommitgt) but I suppose that doesn't work here.