feat(sync): use on-disk content hashing to skip unchanged sync work

[willmruzek]

Summary

• Unchanged targets are detected by comparing a SHA-256 of the content that would be written to a SHA-256 of what’s already on disk. Matching hashes → unchanged: no write, omitted from the applied report.
• Repeat sync with aligned sources and outputs shows Applied changes: None and drops empty per-agent sections.
• Manifest load: strict validation first; if that fails, lenient recovery of outputs rows so pruning still runs after upgrades or slightly non-canonical files; runtime.logWarn when the file can’t be read/parsed, recovery is used, or rows can’t be validated.
• Tests: no-op second sync, drift/restore for commands/rules/skills, missing SKILL.md, stray skill files, registry layout / partial agent failures, and pruning with strict-invalid but recoverable manifests (plus JSON / invalid-row cases).

Details

• Invalid or non-JSON manifest: prior state treated as empty for strict purposes; user sees a warning; stale outputs may not be pruned that run unless rows are lenient-recoverable.

[Copilot]

Pull request overview

This PR upgrades the sync manifest format to v3 by adding a contentHash per output, and uses those hashes to skip rewriting targets whose would-be-written content is unchanged—also simplifying the sync report output for no-op runs.

Changes:

• Bump sync-manifest.json schema to version 3 and require contentHash on every output entry.
• Compute per-target SHA-256 content hashes during sync, detect unchanged targets, and skip writing + omit them from the “Applied changes” report.
• Add an integration test for repeat no-op sync runs and update prune-related fixtures to satisfy the new manifest schema.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
src/lib/sync.ts	Adds manifest v3 schema + content hashing to detect unchanged targets, skip writes, and adjust report rendering.
tests/commands/sync.test.ts	Adds coverage for repeat no-op sync reporting and updates seeded manifests to include contentHash + version 3.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

Comments suppressed due to low confidence (1)

tests/commands/sync.test.ts:195

• The test manifest schema (mockSyncManifestSchema) only asserts agent/kind/name/outputPath. If sync-manifest.json outputs now require a contentHash (per PR description), this schema and the expected manifest row builders should be updated to validate that contentHash exists and is stable across runs (especially in the new no-op sync test).

/** On-disk sync manifest: current schema version, outputs with agent / kind / name / outputPath. */
const mockSyncManifestSchema = z.object({
  version: z.literal(SYNC_MANIFEST_VERSION),
  outputs: z.array(
    z.object({
      agent: z.enum(['copilot', 'cursor']),
      kind: z.enum(['command', 'rule', 'skill']),
      name: z.string().min(1),
      outputPath: z.string().min(1),
    }),
  ),

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

Comments suppressed due to low confidence (2)

tests/commands/sync.test.ts:193

• mockSyncManifestSchema still models outputs as {agent, kind, name, outputPath} only. If the manifest is intended to be v3 and require contentHash per the PR description, this test schema should require contentHash as well so fixtures/tests fail when it is missing.

/** On-disk sync manifest: current schema version, outputs with agent / kind / name / outputPath. */
const mockSyncManifestSchema = z.object({
  version: z.literal(SYNC_MANIFEST_VERSION),
  outputs: z.array(
    z.object({
      agent: z.enum(['copilot', 'cursor']),
      kind: z.enum(['command', 'rule', 'skill']),
      name: z.string().min(1),
      outputPath: z.string().min(1),

tests/commands/sync.test.ts:1660

• This manifest fixture omits the per-output contentHash described as required in the PR. Once the manifest schema is updated to v3, this JSON should include contentHash for every output row (and use the bumped manifest version).

          mockFileSystem,
          path.join(DEFAULT_CONFIG_ROOT, 'sync-manifest.json'),
          JSON.stringify({
            version: SYNC_MANIFEST_VERSION,
            outputs: [
              {
                agent: 'copilot',
                kind: 'command',
                name: 'gone-cmd',

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.