Stackage: lts-10.0: AesonException "Error in $.packages.cassava.constraints.flags['bytestring--lt-0_10_4']: Invalid flag name: \"bytestring--lt-0_10_4\""

[jsynacek]

I'm getting the following error when I try to build my project:

$ stack build
Downloaded lts-10.0 build plan.    
AesonException "Error in $.packages.cassava.constraints.flags['bytestring--lt-0_10_4']: Invalid flag name: \"bytestring--lt-0_10_4\""

Here's my stack.yaml:

$ cat stack.yaml 
resolver: lts-10.0
packages:
- .
extra-deps:
- statvfs-0.2
flags: {}
extra-package-dbs: []

[jsynacek]

Also, in case it matters:

$ stack --version
Version 1.5.1, Git revision 600c1f01435a10d127938709556c1682ecfd694e (4861 commits) x86_64 hpack-0.17.1

[decentral1se]

Hi @jsynacek, thanks for the report. You'll have to do a stack upgrade to get rid of it. That's a well known issue at this point, sorry you hit it. You'll probably also have more luck with Stack issues being raised over at https://github.com/commercialhaskell/stack/issues.

[jsynacek]

Oops, sorry, for some reason, I thought this was a stack issues site. stack upgrade fixed it, thank you!

[decentral1se]

No worries, glad you're back on track ⚡️

[foxjazz]

This still happens, no way to get rid of it.

[DanBurton]

@foxjazz what's your stack --version?

stack upgrade should fix it.

[WhatIfWeDigDeeper]

I received a warning when running stack upgrade

_WARNING: The "stack" executable found on the PATH environment variable is /usr/local/bin/stack, and not the version that was just installed. This means that "stack" calls on the command line will not use this version._

So I forced a re-install

curl -sSL https://get.haskellstack.org/ | sh -s - -f

That fixed the error. Thanks.

[rpapallas]

If on macOS and stack is installed through homebrew then this will _probably_ work for you:

brew link --overwrite haskell-stack