General summary/comments (optional)
If the project uses mixins to hide Prelude from the base package and custom prelude,
compilation result may depend on the stack command order.
Steps to reproduce
Build the following sample stack project.
stack.yaml:
resolver: lts-16.5
packages:
- .
extra-deps:
- morley-prelude-0.3.0@sha256:9e9473ac14cfa206adf0a3700764c0251de05042f1fe45daf9cb8556079ae663,2085
package.yaml:
name: stack-investigation
version: 0.1.0.0
github: "githubuser/stack-investigation"
license: BSD3
author: "Author name here"
maintainer: "example@example.com"
copyright: "2020 Author name here"
extra-source-files:
- README.md
- ChangeLog.md
# Metadata used when publishing your package
# synopsis: Short description of your package
# category: Web
# To avoid duplicated efforts in documentation and dealing with the
# complications of embedding Haddock markup inside cabal files, it is
# common to point users to the README.md file.
description: Please see the README on GitHub at <https://github.com/githubuser/stack-investigation#readme>
dependencies:
- name: base
version: ">= 4.7 && < 5"
mixin: [hiding (Prelude)]
library:
source-dirs: src
dependencies:
- morley-prelude
executables:
stack-investigation-exe:
main: Main.hs
source-dirs: app
ghc-options:
- -threaded
- -rtsopts
- -with-rtsopts=-N
dependencies:
- stack-investigation
- morley-prelude
tests:
stack-investigation-test:
main: Spec.hs
source-dirs: test
ghc-options:
- -threaded
- -rtsopts
- -with-rtsopts=-N
dependencies:
- stack-investigation
- morley-prelude
- network
-
Use clear ~/.stack, .stack-work and run stack test for the current project. The build succeeds.
-
Use clear ~/.stack, .stack-work and run stack build && stack test. The build fails with the following error:
network > [1 of 2] Compiling Main ( /tmp/stack-38b10cd0c119f260/network-3.1.1.1/Setup.hs, /tmp/stack-38b10cd0c119f260/network-3.1.1.1/.stack-work/dist/x86_64-linux-tinfo6/Cabal-3.0.1.0/setup/Main.o )
network >
network > /tmp/stack-38b10cd0c119f260/network-3.1.1.1/Setup.hs:1:8: error:
network > Ambiguous module name `Prelude':
network > it was found in multiple packages:
network > base-4.13.0.0 morley-prelude-0.3.0
network > |
network > 1 | module Main (main) where
network > | ^^^^
Looks like the problem is caused by the fact that network is compiled after morley-prelude
in the latter case, and before it in the former one.
Expected
Both command sequences end in a successful build
Actual
stack build && stack test failed with ambiguous Prelude error.
What actually happened.
Stack version
2.5.0.1
Method of installation
Linux binary from Github release.
Archive with sample project sources
stack-project.zip
General summary/comments (optional)
If the project uses mixins to hide
Preludefrom thebasepackage and custom prelude,compilation result may depend on the
stackcommand order.Steps to reproduce
Build the following sample stack project.
stack.yaml:package.yaml:Use clear
~/.stack,.stack-workand runstack testfor the current project. The build succeeds.Use clear
~/.stack,.stack-workand runstack build && stack test. The build fails with the following error:Looks like the problem is caused by the fact that
networkis compiled aftermorley-preludein the latter case, and before it in the former one.
Expected
Both command sequences end in a successful build
Actual
stack build && stack testfailed with ambiguousPreludeerror.What actually happened.
Stack version
2.5.0.1
Method of installation
Linux binary from Github release.
Archive with sample project sources
stack-project.zip