fix(sync): register inbound sources before evidence in gated apply

[tryeverything24]

what

vouch sync --as-proposals (the gated federation receive path from #536) crashes with an unhandled ValueError whenever the inbound KB carries a receipt-backed claim whose evidence and source are both new to the receiving KB — which is the standard shape for a peer sharing quoted/receipted knowledge.

_sync_apply_as_proposals registers pass-1 substrate in a single walk over sorted(check.new_files). evidence/... sorts ahead of sources/..., so store.put_evidence runs before the evidence's own source has been registered and raises evidence <id> cites unknown source <sha>. the exception is not caught (pass 2 only catches ProposalError), so the whole apply aborts partway:

• vouch sync check has just called the same input ok (_check_graph_integrity deliberately accepts references that arrive in the same sync),
• vouch import-proposals accepts the identical knowledge as a bundle (bundle.import_as_proposals registers all sources before any evidence, exactly to satisfy put_evidence's source-exists guard),
• and any substrate already registered before the crash has no audit event, since sync.apply_proposals is only logged at the end.

fix

split pass 1 into two sub-passes — sources first, then evidence — matching the pass-1 order import_as_proposals already uses. no surface, on-disk, or audit-shape changes.

repro (fails on test, passes on this branch):

peer = KBStore.init(peer_root)
src = peer.put_source(b"the deploy runs at 03:00 UTC every night", title="runbook")
peer.put_evidence(Evidence(id="ev-runbook-span", source_id=src.id,
                           locator="bytes=0-40", quote="the deploy runs at 03:00 UTC every night",
                           byte_start=0, byte_end=40))
peer.put_claim(Claim(id="deploy-time", text="deploys run at 03:00 utc", evidence=["ev-runbook-span"]))

local = KBStore.init(local_root)
sync.sync_apply(local.kb_dir, peer_root, as_proposals=True)   # ValueError before this fix

validation

• new regression test test_sync_apply_as_proposals_registers_sources_before_evidence — confirmed it fails on the previous code (raises at storage.put_evidence) and passes with the fix (verified via git stash)
• python -m pytest tests/ -q --ignore=tests/embeddings — green
• python -m mypy src — no issues in 102 files
• python -m ruff check src tests — all checks passed

changelog entry added under ## [Unreleased] → ### Fixed.

Summary by CodeRabbit

• Bug Fixes

  • Fixed a crash during vouch sync --as-proposals when newly imported evidence references a newly imported source.
  • Sync now completes successfully and records the imported source and evidence correctly.

• Tests

  • Added regression coverage for source and evidence registration during proposal synchronization.

• Documentation

  • Updated the unreleased changelog with details of the fix.

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📥 Commits

Reviewing files that changed from the base of the PR and between 1c9ca7c and 873d7c6.

📒 Files selected for processing (3)

• CHANGELOG.md
• src/vouch/sync.py
• tests/test_sync.py

---

Walkthrough

vouch sync --as-proposals now registers inbound sources before evidence, preventing failures when evidence cites a source arriving in the same sync. A regression test validates registration counts and persisted links, and the changelog documents the fix.

Changes

As-proposals sync ordering

Layer / File(s)	Summary
Register sources before evidence src/vouch/sync.py, tests/test_sync.py, CHANGELOG.md	The sync flow uses separate source and evidence registration passes; regression coverage verifies successful registration and source linkage, and the fix is documented.

Estimated code review effort: 2 (Simple) | ~10 minutes

Possibly related PRs

• vouchdev/vouch#91: Introduces the deterministic vouch sync behavior related to this source-before-evidence ordering.
• vouchdev/vouch#536: Adds a gated import/proposal path with similar substrate import ordering.

Suggested reviewers: plind-junior

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly captures the main change: ordering source registration before evidence in gated sync apply.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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