Skip to content
GitLab
Projects Groups Snippets
  • /
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Sign in / Register
  • GHC GHC
  • Project information
    • Project information
    • Activity
    • Labels
    • Members
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributors
    • Graph
    • Compare
    • Locked Files
  • Issues 5,249
    • Issues 5,249
    • List
    • Boards
    • Service Desk
    • Milestones
    • Iterations
  • Merge requests 582
    • Merge requests 582
  • CI/CD
    • CI/CD
    • Pipelines
    • Jobs
    • Schedules
    • Test Cases
  • Deployments
    • Deployments
    • Releases
  • Analytics
    • Analytics
    • Value stream
    • CI/CD
    • Code review
    • Insights
    • Issue
    • Repository
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Activity
  • Graph
  • Create a new issue
  • Jobs
  • Commits
  • Issue Boards
Collapse sidebar
  • Glasgow Haskell CompilerGlasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #22679
Closed
Open
Issue created Dec 27, 2022 by Matthew Pickering@mpickeringDeveloper

Recompilation checking: ModSummary cache leads to incorrect results in multiple home unit scenarios

The ModSumary cache assumes that each file maps to one Module. With MHUs, this isn't true, each file can be used multiple times, as long as it is only used within one unit once.

One may question whether it is a good idea to allow the same file to be compiled multiple times within one session. However, this is how people have set-up their testsuites in cabal for generations (so internal code can be used for testing), therefore it's better to allow it whilst it doesn't cause any issues.

Therefore we just need to update the key of the cache to also contain a UnitId and we're all good.

This can lead to quite confusing errors on reload in GHCi (when the cache is used).

Edited Dec 27, 2022 by Matthew Pickering
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information
Assignee
Assign to
Time tracking