I built a merge-conflict predictor that ignores lines and reads the AST instead

Description and use

PRISM’s conflict predictor uses AST parsing with tree‑sitter to detect symbol‑level conflicts that Git’s line‑based system misses, reducing production bugs after clean merges.

Problem

Git’s line‑based conflict detection misses semantic conflicts that break production after a clean merge.

Outcome

The predictor identifies semantic merge conflicts that Git’s line‑based system misses, reducing production bugs caused by silent merges.

Workflow

• Parse merge‑base and branch heads into ASTs using tree‑sitter
• Extract symbols (functions, classes, methods) from each AST
• Detect overlap between symbols on both sides
• If overlap exists, compute a risk score and list of symbols
• Expose result via POST /repos/{id}/predict-conflict and a UI with risk bar and symbol list

Evidence

Git's idea of a merge conflict is narrower than it should be. Two branches change the same lines, you get a conflict. Two branches touch the same function from different files and never collide, git merges cleanly and congratulates you.

Source

Parse the merge-base and both branch heads into ASTs with tree-sitter, extract the symbols (functions, classes, methods), and flag overlap between the two sides.

Source

Tree-sitter grammar packages aren't always installed on the machine. The first version crashed when one was missing, which made it a demo, not a tool.

Source

The predictor doesn't replace tests or review. It answers one narrow question: did these two branches step on the same symbols?

Source