haskell/cabal

Local no-index repositories cache leads to bad UX

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#9,136 opened on Jul 18, 2023

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 (5 comments) (0 reactions) (0 assignees)Haskell (1,731 stars) (732 forks)batch import
good first issuere: user experiencetype: enhancement

Description

Describe the bug

It's documented that, when using local no-index repositories.

cabal-install creates a .cache file, and will aggressively use its contents if it exists. Therefore if you change the contents of the directory, remember to wipe the cache too.

but cabal-install offers no warning or message about this leaving the user staring, confused, at a solver failure. See for example #9133.

Expected behavior

Cabal should either

  1. Provide a better caching mechanism, detecting changes to the local repository.
  2. Remnind the user that it will only look at the cache file and that the user should manually delete the cache file if the repository has changed.

Contributor guide

Tech stack
None
Domain
clideveloper experiencetooling
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Knowledge of cabal configurationAbility to read Haskell codeFamiliarity with caching mechanisms
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55
Research direction
Review the cabal documentation on local no index repositories to understand the caching behavior. Examine the cabal source code, likely in the Cabal or cabal install modules, to find where the cache file is written and read. Implement a warning message to remind the user to delete the cache if the repository changes, as an alternative to the more complex caching improvement. Issue #9133 provides additional context.