Use partial SHA1 instead of full platform name and Cabal version on Windows

[anton-dessiatov]

I've had problems using Stack with our project on Windows. The issue was that when installing dependencies (in particular, aeson-pretty-0.7.2), Stack failed to compile Paths_aeson_pretty module because full path to intermediate files exceeded Windows 260 characters limit.

This pull request makes build artifacts path shorter by replacing "platform/cabal" part of it with first 8 characters of Base16-encoded SHA1 of it. In my case, this helped to get aeson-pretty succesfully installed.

[snoyberg]

This has two downsides:

• Paths on Windows will be less user friendly
• Existing built libraries will be affected (likely unusable)

This is still probably a good move, but would you mind emailing the Stack
mailing list for feedback first?

On Tue, Sep 22, 2015, 2:30 PM Anton Dessiatov notifications@github.com
wrote:

I've had problems using Stack with our project on Windows. The issue was
that when installing dependencies (in particular, aeson-pretty-0.7.2),
Stack failed to compile Paths_aeson_pretty module because full path to
intermediate files exceeded Windows 260 characters limit.

This pull request makes build artifacts path shorter by replacing
"platform/cabal" part of it with first 8 characters of Base16-encoded SHA1

of it. In my case, this helped to get aeson-pretty succesfully installed.

You can view, comment on, or merge this pull request online at:

#1027
Commit Summary

• Replace full platform name and cabal version in build artifact path
  on Windows with first 8 symbols of its SHA1 hash. This is done to decrease
  chances of hitting 260 symbol path limit.

File Changes

• M src/Stack/Constants.hs
  https://github.com/commercialhaskell/stack/pull/1027/files#diff-0
  (23)

Patch Links:

• https://github.com/commercialhaskell/stack/pull/1027.patch
• https://github.com/commercialhaskell/stack/pull/1027.diff

—
Reply to this email directly or view it on GitHub
#1027.

[snoyberg]

This is becoming enough of a problem on Windows that I've gone ahead and merged without discussion. The testing we get before the next release will be sufficient.