Cabal does not always rebuild when TH dependency changes

[zliu41]

HLint's EmbedData.hs uses embedFile to load data/hlint.yaml at compile time. embedFile registers the file as a dependency via qAddDependentFile.

When hlint.yaml is modified, and if at least one source hs file is also modified, then cabal correctly rebuilds EmbedData.

However, if we only modify hlint.yaml itself, then cabal v2-build simply prints Up to date and terminates, without building EmbedData.

Environment: GHC 8.10.7, Cabal 3.6.2.0

[Mikolaj]

Duplicate of #4746

[Mikolaj]

@zliu41: thank you for the report. Is that with cabal build or cabal install (#5786)? [Edit: that was already answered in the main issue description, it's build.]

Does adding that file to extra-source-files help?

[zliu41]

@Mikolaj extra-source-files already includes data/*.yaml. I tried adding an explicit data/hlint.yaml in extra-source-files, and that does fix the problem.

According to the user guide, extra-source-files allows wildcards, so this should still be a Cabal bug.

[Mikolaj]

Oh, interesting.

#4746 (comment) may be just about that, but @gbaz knows best.

[gbaz]

This was resolved in #7608 but is not yet in a released cabal I believe.