ghc-pkg and ghc do not agree about package with internal libraries
Initially I reported this to Cabal (https://github.com/haskell/cabal/issues/5857), but I think this is actually a GHC bug.
Repro here: https://github.com/michaelpj/cabal-bug-package-db
In particular, you can run the following.
$ cabal build
$ ghc-pkg field test exposed -f dist/package.conf.inplace
exposed: True
$ ghc-pkg find-module Test -f dist/package.conf.inplace
dist/package.conf.inplace
test-0.1.0.0
$ ghc -package-db dist/package.conf.inplace Use.hs
[1 of 1] Compiling Use ( Use.hs, Use.o )
Use.hs:3:1: error:
Could not load module ‘Test’
It is a member of the hidden package ‘test-0.1.0.0’.
You can run ‘:set -package test’ to expose it.
(Note: this unloads all the modules in the current scope.)
Use -v to see a list of the files searched for.
|
3 | import Test
| ^^^^^^^^^^^
$ ghc -package-db dist/package.conf.inplace -package test Use.hs
[1 of 1] Compiling Use ( Use.hs, Use.o )
That is:
-
ghc-pkg
thinks the package is present, exposed, and contains the module in question. -
ghc
thinks the package is hidden, and will accept it when specified with-package
.
If you comment out the internal library this does not happen, but regardless it seems bad that there's a disagreement between ghc-pkg
and ghc
.
I've also observed (although I don't have a small reproduction for this) a similar case where ghc
does not even think the module is hidden, but again will accept it with -package
.
Trac metadata
Trac field | Value |
---|---|
Version | 8.6.3 |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | ghc-pkg |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |