Change 'optional-packages' default on missing cabal.project

[hasufell]

Fixes #6739

[phadej]

Thanks. I’m not sure whether the behavior we are changing is documented (doesn’t seem so, could you double check). This definitely requires changelog entry. Add a file to `changelog.d`, see other files for examples.

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On 25. Apr 2020, at 19.51, Julian Ospald ***@***.***> wrote:  Fixes #6739 You can view, comment on, or merge this pull request online at: #6740 Commit Summary Change 'optional-packages' default on missing cabal.project File Changes M cabal-install/Distribution/Client/ProjectConfig.hs (5) Patch Links: https://github.com/haskell/cabal/pull/6740.patch https://github.com/haskell/cabal/pull/6740.diff — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[phadej]

I’d remove the field completely. Commit messages tell history, let’s not leave/repeat it in the source :)

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On 25. Apr 2020, at 19.51, Julian Ospald ***@***.***> wrote:  Fixes #6739 You can view, comment on, or merge this pull request online at: #6740 Commit Summary Change 'optional-packages' default on missing cabal.project File Changes M cabal-install/Distribution/Client/ProjectConfig.hs (5) Patch Links: https://github.com/haskell/cabal/pull/6740.patch https://github.com/haskell/cabal/pull/6740.diff — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[hasufell]

Apparently there are multiple references to this default: https://github.com/haskell/cabal/blob/master/Cabal/doc/cabal-project.rst

[tomjaguarpaw]

Thanks for responding to my confusion. I agree that this API is better. On the other hand, I have been bitten by cabal changing its public API a few times in the past and for the sake of others I would be cautious about this going in without a very obvious warning/deprecation cycle.

[phadej]

@tomjaguarpaw We don't have resources to manage warnings&deprecations. Either stuff is changed, or it's not. We'll try to highlight major changes in the changelog.

[phadej]

Specifically, when people upgrade from ancient, say cabal-install-2.0 to cabal-install-3.0 they do miss deprecation warnings etc. I repeat, there is just no resources to manage warnings & deprecations with 2-3 year cycles, so people have chance to notice them. People do not upgrade cabal-install eagerly, so the 2-3 years is justified so they actually could see those warnings.

[tomjaguarpaw]

As you wish. All in all, I do believe the behaviour in this PR is the better one.