Haddock for crypto-api-0.13.3 fails to build with Cabal 3.10.1.0

[mrkkrp]

Describe the bug
Haddock for crypto-api-0.13.3 fails to build with Cabal 3.10.1.0. It appears to work with older versions of Cabal, namely with 3.8.1.0.

First observed here:
https://github.com/mrkkrp/req/actions/runs/5349288540/jobs/9700788692?pr=150#step:10:356

To Reproduce

I was able to reproduce by clonning crypto-api and running cabal haddock from the root of the repo (not entirely sure that it is the same failure as on CI (see link above) but it fails as well).

Expected behavior

cabal haddock should succeed and generate Haddocks.

System information

• Operating system: ubuntu, NixOS
• cabal, ghc versions:

> cabal --version
cabal-install version 3.10.1.0
compiled using version 3.10.1.0 of the Cabal library
> ghc --version
The Glorious Glasgow Haskell Compilation System, version 9.2.7

[ffaf1]

cabal haddock for crypto-api errors with:

haddock: internal error: /home/f/.local/state/cabal/store/ghc-9.2.8/entropy-0.4.1.10-fd9c3ea180d740ecc8140c198284179cb3cf896d39d0ffa0dc35962213abb815/share/doc/html/doc-index.json: openBinaryFile: does not exist (No such file or directory)
Error: cabal: Failed to build documentation for crypto-api-0.13.3.

lsinsg that folder:

doc-index.html  entropy.haddock  haddock-bundle.min.js  index.html  linuwial.css  meta.json  quick-jump.css  synopsis.png  System-Entropy.html

See #8326.

[ffaf1]

From Haddock #1488, it seems it shold have been fixed and backported in GHC ≥ 9.2.4, so I wonder what is happening.

[mrkkrp]

Is there a workaround?

[ulysses4ever]

@mrkkrp there's a delicate relationship between versions inside the ghc-cabal-haddock triad. It appears that the bug disappears on GHC 9.2 + Cabal 3.8 (but you already knew it) and on GHC 9.4+ (including 9.6) + Cabal 3.10.

[ulysses4ever]

@coot you contributed the original fix for this issue I believe. Do you understand why GHC 9.2 with latest patches (e.g. 9.2.8) still suffers from it but only with Cabal 3.10? And more importantly, is there anything we could do (especially on the Cabal end) to make Cabal 3.10.x work with GHC 9.2? As it stands, this issue blocks the recommended badge in ghcup; we almost agreed to put it on the upcoming 3.10.2, but not anymore after we found out that the combination of 3.10 and 9.2 is still broken...

[ulysses4ever]

I just checked the haddock branches and the ghc-9.2 branch doesn't have the fix from haskell/haddock#1488 ghc-9.4 (and on, i assume) does have it. @ffaf1 where did you get the info about it being

backported in GHC ≥ 9.2.4

? (Btw, thanks a lot for looking up haskell/haddock#1488!)

The only mystery remaining is why Cabal <3.10 works...

[ffaf1]

backported in GHC ≥ 9.2.4

I don’t know what I was reading, sorry for spreading misinfo.

Depending on GHCup choices, this might be something quite important.