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Weave – A language aware merge algorithm based on entities

Weave – A language aware merge algorithm based on entities

rs545837

Comments (63)

  • gritzko
    At this point, the question is: why keep files as blobs in the first place. If a revision control system stores AST trees instead, all the work is AST-level. One can run SQL-level queries then to see what is changing where. Like - do any concurrent branches touch this function? - what new uses did this function accrete recently? - did we create any actual merge conflicts? Almost LSP-level querying, involving versions and branches. Beagle is a revision control system like that [1]It is quite early stage, but the surprising finding is: instead of being a depository of source code blobs, an SCM can be the hub of all activities. Beagle's architecture is extremely open in the assumption that a lot of things can be built on top of it. Essentially, it is a key-value db, keys are URIs and values are BASON (binary mergeable JSON) [2] Can't be more open than that.[1]: https://github.com/gritzko/librdx/tree/master/be[2]: https://github.com/gritzko/librdx/blob/master/be/STORE.md
  • rs545837
    Some context on the validation so far: Elijah Newren, who wrote git's merge-ort (the default merge strategy), reviewed weave and said language-aware content merging is the right approach, that he's been asked about it enough times to be certain there's demand, and that our fallback-to-line-level strategy for unsupported languages is "a very reasonable way to tackle the problem." Taylor Blau from the Git team said he's "really impressed" and connected us with Elijah. The creator of libgit2 starred the repo. Martin von Zweigbergk (creator of jj) has also been excited about the direction. We are also working with GitButler team to integrate it as a research feature.The part that's been keeping me up at night: this becomes critical infrastructure for multi-agent coding. When multiple agents write code in parallel (Cursor, Claude Code, Codex all ship this now), they create worktrees for isolation. But when those branches merge back, git's line-level merge breaks on cases where two agents added different functions to the same file. weave resolves these cleanly because it knows they're separate entities. 31/31 vs git's 15/31 on our benchmark.Weave also ships as an MCP server with 14 tools, so agents can claim entities before editing, check who's touching what, and detect conflicts before they happen.
  • _flux
    How does it compare to https://mergiraf.org/ ? I've had good experience with it so far, although I rarely even need it.It's also based on treesitter, but probably otherwise a more baseline algorithm. I wonder if that "entity-awareness" actually then brings something to the table in addition to the AST.edit: man, I tried searching this thread for mention of the tool for a few times, but apparently its name is not mergigraf
  • keysersoze33
    Interesting that Weave tries to solve Mergiref's shortcomings (also Tree-sitter based):> git merges lines. mergiraf merges tree nodes. weave merges entities. [1]I've been using mergiraf for ~6 months and tried to use it to resolve a conflict from multiple Claude instances editing a large bash script. Sadly neither support bash out of the box, which makes me suspect that classic merge is better in this/some cases...Will try adding the bash grammar to mergiraf or weave next time[1] https://ataraxy-labs.github.io/weave/
  • 50lo
    If both sides refactor the same function into multiple smaller ones (extract method) or rename it, can Weave detect that as a structural refactor, or does it become “delete + add”? Any heuristics beyond name matching?
  • sea-gold
    Website: https://ataraxy-labs.github.io/weave/I haven't tried it but this sounds like it would be really valuable to me.
  • spacecrafter3d
    Awesome, I've been wanting this for a long time! Any chance of Swift being supported?
  • taejavu
    I tried this with the kind of merge conflict I'd expect it to solve automatically, and it didn't. Is it supposed to work while rebasing, or is it strictly for merges?
  • WalterGR
    It’s described as a “merge driver for Git”. Is it usable independently of git? Can I use it to diff arbitrary files?
  • anon
    undefined
  • alkonaut
    > This happens constantly when multiple AI agents work on the same codebaseWhat?Is the idea of "multiple agents" of flesh and blood writing code that far fetched now?
  • kelseydh
    Very cool, would love to see Ruby support added.
  • SurvivorForge
    The entity-level approach is a meaningful step up from line-based merging. Anyone who has dealt with a merge conflict where git splits a function signature across conflict markers knows how much context is lost at the line level. Curious how this handles languages with significant whitespace like Python, where indentation changes can shift the semantic meaning of entire blocks.
  • anon
    undefined
  • Palanikannan
    Dude, I tried this for a huge merge conflict and was able to auto resolve so much and came across sem for giving my agents context on what changed for reviewing some code and surprisingly, I feel git is done for good. Much less tokens, and much more accurate, I can see something big out of this, things like weave come once in a century
  • esafak
    Are agents any good with it?