Add cabal get --only-package-description

[ulysses4ever]

This is based on #1977 and #5162, with a hope to finally close #1954.

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Please include the following checklist in your PR:

• 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.

Please also shortly describe how you tested your change. Bonus points for added tests!

[ulysses4ever]

Apart from modernizing the old code, I added a bit of docs and a changelog as requested by @jneira on #5162.

[ulysses4ever]

If anyone could help me with a test, I'd add one. My attempt so far:

import Test.Cabal.Prelude
main = cabalTest $ do
  -- cabal "update" [] -- could add that but it has no visible effect
  cabal
    "get"
    [ "text", "--only-package-description" ]

Which gives me:

-----BEGIN CABAL OUTPUT-----
Error: cabal: There is no package named 'text'. 
You may need to run 'cabal update' to get the latest list of available packages.
-----END CABAL OUTPUT-----

If add cabal "update" [] before the get, I get another error before that "no package names text" one:

-----BEGIN CABAL OUTPUT-----
No remote repositories configured
-----END CABAL OUTPUT-----

[ffaf1]

Is this bit from cabal-testsuite/README.md helpful? ``` **How can I add a dependency on a package from Hackage in a test?** By default, the test suite is completely independent of the contents of Hackage, to ensure that it keeps working across all GHC versions. If possible, define the package locally. If the package needs to be from Hackage (e.g., you are testing the global store code in new-build), use `withRepo "repo"` to initialize a "fake" Hackage with the packages placed in the `repo` directory. ``` Il 03 luglio 2022 alle 09:35 Artem Pelenitsyn ha scritto:

…

If anyone could help me with a test, I'd add one. My attempt so far: ``` import Test.Cabal.Prelude main = cabalTest $ do -- cabal "update" [] -- could add that but it has no visible effect cabal "get" [ "text", "--only-package-description" ] ``` Which gives me: ``` -----BEGIN CABAL OUTPUT----- Error: cabal: There is no package named 'text'. You may need to run 'cabal update' to get the latest list of available packages. -----END CABAL OUTPUT----- ``` If add `cabal "update" []` before the `get`, I get another error before that "no package names `text`" one: ``` -----BEGIN CABAL OUTPUT----- No remote repositories configured -----END CABAL OUTPUT----- ``` -- Reply to this email directly or view it on GitHub: #8263 (comment) You are receiving this because you are subscribed to this thread. Message ID: ***@***.***>

[jneira]

Many thanks for continuing the work of #5162
It looks good to me, although a test would help to get it merged
Pinging @fgaz @gbaz as they talked about the relevance of the feature

[ulysses4ever]

@ffaf1 thanks a lot for the pointer. @jneira a test added.

[Mikolaj]

LGTM

[jneira]

perfect, many thanks for leveraging and completing the existing work