'package.cache' conflict with multiple haskell_library deps

[jin]

Take the following example BUILD file from https://github.com/jin/bazel_haskell_example:

haskell_binary(
    name = "main",
    srcs = ["Main.hs"],
    deps = [
	":a",
	":b",
    ],
)

haskell_library(
    name = "a",
    srcs = ["A.hs"],
)


haskell_library(
    name = "b",
    srcs = ["B.hs"],
)

This throws an error:

→ bazel build :main
ERROR: /Users/jin/Code/rules_haskell_conflict_error/BUILD:18:1: generated file 'package.cache' in rule 'b' conflicts with existing generated file from rule 'a', defined at /Users/jin/Code/rules_haskell_conflict_error/BUILD:12:1.
ERROR: error loading package '': Package '' contains errors.
INFO: Elapsed time: 0.051s

[jin]

I guess the problem is even simpler: having two haskell_library rules in the same package throws the same loading phase error.

haskell_library(
    name = "a",
    srcs = ["A.hs"],
)


haskell_library(
    name = "b",
    srcs = ["B.hs"],
)

[Fuuzetsu]

Interesting, I wonder if they share directories so it's counting it as same output… Thanks for reporting, it's very much WIP.