unisonweb/unison

externally updated `_head` isn't detected in `ucm`

Open

#886 opened on Oct 23, 2019

View on GitHub
 (0 comments) (0 reactions) (0 assignees)Haskell (304 forks)batch import
bugcodebase-manager / ucmhelp wanted

Repository metrics

Stars
 (6,624 stars)
PR merge metrics
 (Avg merge 10d 2h) (5 merged PRs in 30d)

Description

This can cause weirdness if there are two instances of ucm running backed by the same codebase.

I think the code to do anything about it is commented out (which we should fix) but there is code to display a warning, which also isn't firing.

If the external change leaves multiple heads, ucm should first:

  • issue a message to the console, including the short hashes of the previous loopstate root hash, and of the newly detected heads (see reflog implementation for example of printing short hashes).
  • merge the multiple heads (Branch.merge?)

Then (multiple heads or single head), ucm should:

  • write the external change to the reflog
  • update LoopState

Contributor guide

Research direction
Inspect the code that detects external head changes in the UCM loop state. Find the commented out logic and uncomment/fix it. Implement the warning message with short hash printing (see reflog for example). Add logic to merge multiple heads using Branch.merge. Write external changes to the reflog and update LoopState accordingly.
Tech stack
None
Domain
cli
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.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GitHaskell
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
70