Hackage name collision while using stack solver with extra-deps

Question

Well it turns out that my app name is the same as one of the packages that is uploaded to hackage, so when I try to resolver extra dependencies using stack solver --resolver lts 7.12, I get the following error:

$ stack solver --resolver lts-7.12
Using configuration file: stack.yaml
Using cabal packages:
- html-parse.cabal

Using resolver: lts-7.12
Using compiler: ghc-8.0.1
Asking cabal to calculate a build plan...
Trying with packages from lts-7.12 as hard constraints...
Attempt failed.

>>>> Cabal errors begin
cabal.exe: Could not resolve dependencies:
next goal: html-parse (user goal)
rejecting: html-parse-0.2.0.0, 0.1.0.0 (global constraint requires ==0.0.0.3)
trying: html-parse-0.0.0.3
next goal: hunit (dependency of html-parse-0.0.0.3)
Dependency tree exhaustively searched.
<<<< Cabal errors end

Could not parse cabal-install errors:

>>>> Cabal errors begin
cabal.exe: Could not resolve dependencies:
next goal: html-parse (user goal)
rejecting: html-parse-0.2.0.0, 0.1.0.0 (global constraint requires ==0.0.0.3)
trying: html-parse-0.0.0.3
next goal: hunit (dependency of html-parse-0.0.0.3)
Dependency tree exhaustively searched.
<<<< Cabal errors end

My app/package name in .cabal file is html-parse and the current version is 0.0.0.3. It looks like my own package is listed as a dependency with a constraint of ==0.0.0.3, but there is another pacakge on hackage that has the same name but different versions.

Can I somehow solve this issue without renaming my own app?

duplode duplode · Accepted Answer · 2016-12-08T11:33:42

Quoting the Cabal user guide (emphasis mine):

Package names and versions

All packages have a name, e.g. “HUnit”. Package names are assumed to be unique. Cabal package names can use letters, numbers and hyphens, but not spaces. The namespace for Cabal packages is flat, not hierarchical.

Accordingly, the Cabal library doesn't have a feature for handling package name conflicts, and neither do cabal-install nor stack. That being so, you will have to rename your package.

P.S.: I am deliberately not considering seriously the possibility of setting up your project to use a private Hackage that excludes the homonymous package, both because I don't know how it would play out in practice and because it is vastly more trouble than it is worth.

Hackage name collision while using stack solver with extra-deps

1 Answers