ux: add warning when cabal reads from no index cache

[taimoorzaeem]

Fixes #9136.

Since, I am a new contributor, I didn't follow the provided PR template and wrote what I thought would be best in this PR. Let me know if following the provided PR template is necessary.

• [x] Add warning in code
• [ ] Add tests
• [ ] Add QA Notes
• [ ] Conform to coding conventions

@andreabedini Please check if that is the right place for the warning and let me know about changes. I'll work on adding the tests next.

[ulysses4ever]

@taimoorzaeem great work, thanks!

Could you, please, add manual-QA notes in the PR description? This would be a step-by-step guide showing what it takes to see the effect of your patch locally. This will start with build cabal from your branch (obvious). But then, what do I do to see the warning? Step by step. You could attach any sample files that could help to set up a no-index repository etc. Example of MQA notes is in the description of https://github.com/haskell/cabal/pull/9200

[ulysses4ever]

You'll also have to make fourmolu and whitespace checkers happy (see the github action failures linked from this page).

[ulysses4ever]

Would be great to add a test. See for guidance: https://github.com/haskell/cabal/blob/master/cabal-testsuite/README.md#how-to-write

[taimoorzaeem]

@ulysses4ever @andreabedini When exactly does cabal create a local .cache file? Are there any example of such test cases that I can follow?

[ulysses4ever]

@taimoorzaeem I don't know the answer to your last question from the top of my head, sadly. I could try to dig over the weekend maybe. But in the meantime: can you locally observe the effect of your patch? In other words, the message you added --- can you make cabal built with this patch print this message? If so, please, post the instructions for how to do that.

[ulysses4ever]

37 tests affected by the current change (they fail now), but most (all?) of them are seemingly unrelated:

562 tests, 14 skipped, 0 unexpected passes, 37 unexpected fails. UNEXPECTED FAIL: PackageTests/ShowBuildInfo/Complex/single.test.hs PackageTests/HaddockArgs/quickjump.test.hs PackageTests/HaddockArgs/hoogle.test.hs PackageTests/ConditionalAndImport/cabal.test.hs PackageTests/HaddockProject/haddock-project.test.hs PackageTests/NewFreeze/Flags/new_freeze.test.hs PackageTests/NewFreeze/FreezeFile/new_freeze.test.hs PackageTests/NewFreeze/BuildTools/new_freeze.test.hs PackageTests/BuildTargets/UseLocalPackageForSetup/use-local-package-as-setup-dep.test.hs PackageTests/BuildTargets/UseLocalPackage/use-local-version-of-package.test.hs PackageTests/Backpack/Includes3/cabal-repo.test.hs PackageTests/Backpack/T6385/cabal.test.hs PackageTests/Regression/T9756/cabal.test.hs PackageTests/Regression/T9640/cabal.test.hs PackageTests/NewHaddock/DisableDoc/cabal.test.hs PackageTests/NewHaddock/HaddockOutput/HaddockOutputCmd/cabal.test.hs PackageTests/NewHaddock/HaddockOutput/HaddockOutputConfig/cabal.test.hs PackageTests/NewHaddock/ImplyDependencies/cabal.test.hs PackageTests/OfflineFlag/offlineFlag.test.hs PackageTests/Outdated/outdated.test.hs PackageTests/Outdated/outdated-project-file.test.hs PackageTests/Outdated/outdated_freeze.test.hs PackageTests/VersionPriority/3-web.test.hs PackageTests/VersionPriority/2-local.test.hs PackageTests/VersionPriority/1-web.test.hs PackageTests/VersionPriority/1-local.test.hs PackageTests/VersionPriority/0-local.test.hs PackageTests/VersionPriority/2-web.test.hs PackageTests/Get/OnlyDescription/cabal.test.hs PackageTests/ExtraPackages/cabal.test.hs PackageTests/CopyHie/cabal.test.hs PackageTests/HaddockBuildDepends/cabal.test.hs PackageTests/Freeze/enable-benchmarks.test.hs PackageTests/Freeze/disable-tests.test.hs PackageTests/Freeze/disable-benchmarks.test.hs PackageTests/Freeze/freeze.test.hs PackageTests/Freeze/enable-tests.test.hs

[taimoorzaeem]

can you locally observe the effect of your patch? In other words, the message you added --- can you make cabal built with this patch print this message? If so, please, post the instructions for how to do that.

No, I am not able to observe the effect locally. That's because I am not sure when exactly cabal create a local no index cache. The warning message is only supposed to be printed when this cache file is created by cabal. Since I am not a much advanced user of cabal, I would like some you folks' help. @andreabedini Could you help out on how I should go about testing/qa it locally?