rules_haskell does not build with incompatible_disallow_empty_glob

[limdor]

See: https://buildkite.com/bazel/bazelisk-plus-incompatible-flags/builds/1320#018435e1-7742-44cb-911b-c21b89fb6e95

[avdv]

Noticed this error from the buildkite output:

(01:20:20) ERROR: Traceback (most recent call last):

	File "/var/lib/buildkite-agent/builds/bk-docker-6w0f/bazel-downstream-projects/rules_haskell/tests/stackage_zlib_runpath/BUILD.bazel", line 42, column 31, in <toplevel>

		srcs = glob(["**"]) + glob(["cabal_binary/**"]),

Error in glob: glob pattern 'cabal_binary/**' didn't match anything, but allow_empty is set to False (the default value of allow_empty can be set with --incompatible_disallow_empty_glob).

Is this a bug in Bazel? IMO, the pattern cabal_binary/** should match all files recursively inside the cabal_binary folder (there are two), but now it does not?

Using cabal_binary/* instead fixes the problem. But why is this?

[limdor]

It matches every file in every subdirectory. There is no subdirectory here.
The logic of logic is a bit complex, that is why some patterns are discouraged.
In the documentation the explanation is relatively complete with some examples included
https://bazel.build/reference/be/functions#glob

[limdor]

If you want to glob everything recursively you should do cabal_binary/**/*

[avdv]

Sorry for the noise, this actually works as intended, but one of the places where that specific pattern is used, has a typo 🙈

cabal-binary/** vs. cabal_binary/**

[limdor]

Ah ok, I did not see the typo