oh-my-opencode-slim/src/hooks/apply-patch/codemap.md

apply-patch

Responsibility

Provide a resilient preprocessor for tool.execute.before on apply_patch that rewrites recoverable stale hunks, validates workspace boundaries, and blocks unsafe patches before they reach OpenCode’s native patch executor.

Design

• Entry point is createApplyPatchHook in index.ts, bound to tool.execute.before.
• rewritePatch (operations.ts) is the main pipeline used by the hook and is backed by:
  • parseValidatedPatch / createPatchExecutionContext (execution-context.ts) for patch parsing and path/state validation.
  • parsePatch / parsePatchStrict / formatPatch (codec.ts) for patch AST conversion and serialization.
  • resolveChunkStart, locateChunk, resolveUpdateChunks, applyHits (resolution.ts) for context matching.
  • resolveBy... helpers in matching.ts (seek, seekMatch, list, rescueByPrefixSuffix, rescueByLcs) for tolerant matching.
• types.ts defines domain contracts used across modules (PatchChunk, PatchHunk, ResolvedChunk, ApplyPatchErrorKind, etc.).
• Error semantics are centralized in errors.ts (ApplyPatchError, createApplyPatchBlockedError, createApplyPatchVerificationError, isApplyPatchError) and surfaced in hook logging and thrown errors.
• No additional runtime configuration is exposed; behavior is controlled by constant APPLY_PATCH_RESCUE_OPTIONS (prefixSuffix + lcsRescue).

Flow

1. createApplyPatchHook filters only input.tool === 'apply_patch'.
2. It requires output.args.patchText to be a string.
3. It resolves root and worktree from input.directory / ctx.directory / ctx.worktree.
4. It calls rewritePatch(root, patchText, options, worktree).
5. On result.changed, it replaces output.args.patchText with canonicalized patch text.
6. On failure, it normalizes to ApplyPatchError, logs blocked | validation | verification | internal, and rethrows so native execution is prevented.

Integration

• Consumed by src/index.ts through createApplyPatchHook.
• Acts before native tool execution via OpenCode hook point tool.execute.before.
• Downstream dependencies include ctx.client indirectly only for context, and utils/logger for structured hook telemetry.
• Uses Patch parser/resolver modules to keep new_lines byte-preserving while only mutating stale anchors and chunk context.