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Support ghc-9.14 - #827

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Support ghc-9.14#827
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erikd/ghc-9.14

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@erikd

@erikd erikd commented Mar 5, 2026 •
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Description

Support ghc-9.14 exncluding adding it to CI.

The tests found a bug in the code which is only triggered when compiling with ghc-9.14 due to changes in strictness analysis and optimisation behavior. Using Claude I have come up with a fix for that, but I am still validating that fix which will be in a later PR and I will then include ghc-9.14 to CI.

Checklist

  • Read our contribution guidelines at CONTRIBUTING.md, and make sure that this PR complies with the guidelines.

@erikd
erikd force-pushed the erikd/ghc-9.14 branch 2 times, most recently from 0fe8598 to acac990 Compare March 6, 2026 05:49
@erikd
erikd force-pushed the erikd/ghc-9.14 branch 3 times, most recently from 4b16e72 to efdb4e4 Compare March 6, 2026 08:58
@erikd
Improve usage of GHC warnings
c5ebc46 
* Remove usage of -Wno-x-partial from cabal file where it
  is not needed.
* Disable -Wredundant-constraint warning for ghc >= 9.14.
* Disable -Wpattern-namespace-specifier for ghc >= 9.14.
@erikd

erikd commented Mar 9, 2026

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I have logged a GHC ticket https://gitlab.haskell.org/ghc/ghc/-/issues/27005 asking if this is a ghc-9.14 optimization bug.

If it is a bug this PR still makes sense, but we might want to wait for a fix before adding ghc-9.14 to CI.

jorisdral
jorisdral approved these changes Mar 9, 2026
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Thank you!

Could you also add changelog entries for blockio and lsm-tree? Something along the lines of:

* Support `ghc-9.14`. See [PR #827](https://github.com/IntersectMBO/lsm-tree/pull/827)

Comment thread lsm-tree/lsm-tree.cabal
Comment thread lsm-tree/lsm-tree.cabal
Comment thread blockio/blockio.cabal
@jorisdral

jorisdral commented Mar 9, 2026

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BTW, I might hold off on merging this PR just until we know the fix for ghc-9.14 works

@jorisdral jorisdral linked an issue Mar 10, 2026 that may be closed by this pull request
Support ghc-9.14 #813
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@erikd

erikd commented Mar 12, 2026

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Turns out that the tests in this repo uncovered a bug in GHC.
See: https://gitlab.haskell.org/ghc/ghc/-/issues/27005 and https://gitlab.haskell.org/ghc/ghc/-/merge_requests/15688

@erikd

erikd commented Mar 13, 2026

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This PR is on hold until ghc-9.14.2 (which should contain a bug fix for the issue discovered).

I will switch it to "draft" mode.

@erikd
erikd marked this pull request as draft March 13, 2026 04:56
@jorisdral jorisdral mentioned this pull request Apr 10, 2026
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@jorisdral

jorisdral commented Jul 20, 2026

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We merged #859, which has a workaround for the GHC issue you linked to. Are you happy for me to close your PR, or is there something that should still be merged into main?

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@jorisdral jorisdral jorisdral approved these changes
@dcoutts dcoutts Awaiting requested review from dcoutts dcoutts is a code owner
@mheinzel mheinzel Awaiting requested review from mheinzel mheinzel is a code owner

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Support ghc-9.14

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