haddock test related failures with GHC 9.0.2 and 9.2.{1,2,3}

[andreabedini]

From #7952 (comment)

The following tests fail on GHC 9.0.2 (but not GHC 9.0.1) on both Linux and Mac

• PackageTests/Backpack/Includes2/setup-external.test.hs
• PackageTests/Backpack/Includes3/setup-external-ok.test.hs
• PackageTests/Backpack/Includes2/setup-per-component.test.hs

A failed run is https://github.com/haskell/cabal/runs/5178990935?check_suite_focus=true#step:10:1374

In all cases, the error happens while dealing with haddock. The relevant part of the log is:

Warning: The documentation for the following packages are not installed. No links will be generated to these packages: base-4.15.1.0, ghc-bignum-1.1, ghc-prim-0.7.0, Includes2-0.1.0.0
creating setup-per-component.dist/work/dist/doc/html/Includes2
/usr/local/.ghcup/ghc/9.0.2/bin/haddock-ghc-9.0.2 '@setup-per-component.dist/work/dist/doc/html/Includes2/haddock-response24859-1.txt'
   0% (  0 /  3) in 'Mine'
  Missing documentation for:
    Module header
    Mine (mylib/Mine.hs:3)
    mine (mylib/Mine.hs:4)
haddock: internal error: haddock:iface
CallStack (from HasCallStack):
  error, called at utils/haddock/haddock-api/src/Haddock/Interface.hs:178:16 in main:Haddock.Interface

[Mikolaj]

@Kleidukos, @wz1000: any cheap shot at why this fails with 9.0.2 and not 9.0.1?

[wz1000]

Might be related to https://gitlab.haskell.org/ghc/ghc/-/issues/20903

[Kleidukos]

No idea on my end :(

[Mikolaj]

Thanks.

@hasufell: I guess you had no reports of 9.0.2 having missing/broken haddocks in the Linux package, as distributed by ghcup? Probably not the case, but just checking.

[wz1000]

Some 9.0.2 distributions (all the hadrian generated ones in fact - which would be the fedora one IIRC) also don't have haddocks.

[Mikolaj]

@wz1000: thank you. So nothing to worry about. It'll get fixed in 9.0.3, if it gets released.

@andreabedini: how would you mark the failures as expected so that we remember to unmark then when 9.0.3 is out? Perhaps we should leave this ticket open to remember? Change the ticket title mentioning 9.0.3 and adding lots of exclamation marks?

[hasufell]

@hasufell: I guess you had no reports of 9.0.2 having missing/broken haddocks in the Linux package, as distributed by ghcup? Probably not the case, but just checking.

No idea

[andreabedini]

@andreabedini: how would you mark the failures as expected so that we remember to unmark then when 9.0.3 is out? Perhaps we should leave this ticket open to remember? Change the ticket title mentioning 9.0.3 and adding lots of exclamation marks?

@Mikolaj Given all three failures seem to be related to haddock, I'd say we can use this ticket, either as it as it is or changing the title. The ticket is also mentioned in the workflow so we can be reminded from there too.