Adding a --haddock-option rebuilds the world

[mitchellwrosen]

To reproduce:

• cabal new-haddock
• cabal new-haddock --haddock-option=--hyperlink-source

This appears to rebuild the world due to a flag change, but it shouldn't have to. Only the haddocks need to be regenerated.

[23Skidoo]

/cc @merijn, I believe your work is relevant

[merijn]

Which version of cabal-install is this happening in? When I added the GHC flag filtering stuff I also added a filter which drops all haddock flags, so this should be fixed in HEAD.

[merijn]

@mitchellwrosen Is this issue still relevant?

[mitchellwrosen]

@merijn Well, my repro steps are rather clear, no?

But yes, I just tested again, and the issue is still relevant.

[mitchellwrosen]

Hm, maybe I spoke too soon. Did the --haddock-option flag get removed from cabal? I do see cabal reconfigure, but then it mysteriously fails with no output:

cabal-3.2.0.0: '/Users/mitchell/.ghcup/bin/haddock' exited with an error:

cabal: Failed to build documentation for blahblah-0.1.0.

However, the alias for this particular flag

cabal haddock --haddock-hyperlink-source

does appear to reconfigure the library, not rebuild the Haskell modules, and generate haddocks, as expected.