Make ingester job retry idempotent against a live sibling

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 - SQLite ingester queue runs with a multi-connection pool (`pool_size=5, max_overflow=5`) instead of a single connection. API reads (`/stats`, `/jobs`) no longer time out with `QueuePool limit of size 1 reached` while workers hold the connection.
 - Permanently-failed ingester documents (revisioned sources) record their revision in `sync_state`, so discovery no longer re-enqueues them every sweep; re-attempted only when the file's revision changes or via explicit retry/rebuild.
+- Retrying a dead ingester job (`/jobs/{id}/retry`, `/dlq/{id}/retry`) when a live job already exists for the same `(source_id, uri)` returns the live job instead of failing with a 500 (`uq_jobs_live` violation).
 
 ## [0.58.0] - 2026-06-15
 

haiku_rag_slim/haiku/rag/ingester/queue/repository.py

@@ -7,6 +7,7 @@ from datetime import UTC, datetime, timedelta
 import sqlalchemy as sa
 from sqlalchemy.dialects import postgresql
 from sqlalchemy.dialects import sqlite as sqlite_dialect
+from sqlalchemy.exc import IntegrityError
 from sqlalchemy.ext.asyncio import AsyncEngine
 
 from haiku.rag.ingester.queue.db import jobs, sync_state
@@ -242,7 +243,12 @@ class JobRepo:
         error cleared, scheduled for immediate re-claim. Refuses `claimed`
         rows (would race with the worker still processing) and `succeeded`
         rows (re-ingest via UPSERT instead). Raises KeyError when the row
-        is missing or in a non-retryable state."""
+        is missing or in a non-retryable state.
+
+        Idempotent against a live sibling: if a live (queued/claimed) job
+        already exists for the same (source_id, uri), reviving the dead row
+        would violate `uq_jobs_live`; instead the existing live job is returned
+        and the dead row is left dead."""
         now = _utcnow_iso()
         stmt = (
             sa.update(jobs)
@@ -258,11 +264,38 @@ class JobRepo:
             )
             .returning(*jobs.c)
         )
-        async with self._engine.begin() as conn:
-            row = (await conn.execute(stmt)).mappings().one_or_none()
-        if not row:
-            raise KeyError(f"Job {job_id!r} not found or not retryable")
-        return _row_to_job(row)
+        collided = False
+        try:
+            async with self._engine.begin() as conn:
+                row = (await conn.execute(stmt)).mappings().one_or_none()
+        except IntegrityError:
+            collided = True
+            row = None
+        if row is not None:
+            return _row_to_job(row)
+        if collided:
+            target = await self.get_job(job_id)
+            if target is not None:
+                live = await self._live_sibling(target.source_id, target.uri)
+                if live is not None:
+                    return live
+        raise KeyError(f"Job {job_id!r} not found or not retryable")
+
+    async def _live_sibling(self, source_id: str, uri: str) -> Job | None:
+        """The live (queued/claimed) job for a (source_id, uri), if any.
+        `uq_jobs_live` guarantees at most one."""
+        query = (
+            sa.select(jobs)
+            .where(
+                jobs.c.source_id == source_id,
+                jobs.c.uri == uri,
+                jobs.c.status.in_(["queued", "claimed"]),
+            )
+            .limit(1)
+        )
+        async with self._engine.connect() as conn:
+            row = (await conn.execute(query)).mappings().one_or_none()
+        return _row_to_job(row) if row else None
 
     async def cancel(self, job_id: str) -> bool:
         """True iff a queued/claimed row was removed; terminal jobs aren't

tests/ingester/test_api.py

@@ -139,7 +139,7 @@ async def test_protected_endpoint_accepts_correct_token(state):
 
 
 @pytest.mark.asyncio
-async def test_no_auth_token_allows_everything(state, jobs):
+async def test_no_auth_token_allows_everything(state):
     async with _client(state, auth_token=None) as client:
         assert (await client.get("/jobs")).status_code == 200
         assert (await client.get("/health")).status_code == 200
@@ -332,6 +332,24 @@ async def test_dlq_retry_404_on_missing_job(state):
     assert resp.status_code == 404
 
 
+@pytest.mark.asyncio
+async def test_dlq_retry_with_live_sibling_returns_200(state, jobs):
+    """Retrying a dead job when a live job already exists for the same
+    (source_id, uri) returns 200 with the live job, not a 500."""
+    first = await jobs.enqueue("src", "u", JobOp.UPSERT)
+    assert first is not None
+    claimed = await jobs.claim_next("w")
+    assert claimed is not None
+    await jobs.mark_dead(first.id, "err", "w")
+    live = await jobs.enqueue("src", "u", JobOp.UPSERT)
+    assert live is not None
+
+    async with _client(state) as client:
+        resp = await client.post(f"/dlq/{first.id}/retry")
+    assert resp.status_code == 200
+    assert resp.json()["id"] == live.id
+
+
 # --- /sources ---
 
 
@@ -340,16 +358,17 @@ class _StubSource:
         self.source_id = source_id
         self._sweeps = list(sweeps)
 
-    def supports(self, uri):  # pragma: no cover
+    def supports(self, _uri):  # pragma: no cover
         return True
 
-    async def head(self, uri):  # pragma: no cover
+    async def head(self, _uri):  # pragma: no cover
         return None
 
-    async def fetch(self, uri) -> FetchResult:  # pragma: no cover
+    async def fetch(self, _uri) -> FetchResult:  # pragma: no cover
         raise NotImplementedError
 
     async def discover(self, since=None, *, known_uris=None):
+        del since, known_uris  # interface-required, unused by this stub
         events = self._sweeps.pop(0) if self._sweeps else []
         for event in events:
             yield event
@@ -501,7 +520,7 @@ async def test_providers_probes_each_docling_serve_url(state, monkeypatch):
     from haiku.rag.ingester.api.routes import providers as providers_mod
     from haiku.rag.ingester.api.schemas import ProviderEndpoint
 
-    async def _fake_probe(client, base_url):
+    async def _fake_probe(_client, base_url):
         if "down" in base_url:
             return ProviderEndpoint(
                 base_url=base_url,
@@ -539,7 +558,7 @@ async def test_providers_skips_docling_serve_when_not_in_use(state, monkeypatch)
 
     probed: list[str] = []
 
-    async def _spy_probe(client, base_url):  # pragma: no cover - asserted not called
+    async def _spy_probe(_client, base_url):  # pragma: no cover - asserted not called
         probed.append(base_url)
         raise AssertionError("probe should not run when docling-serve is not in use")
 
@@ -562,7 +581,7 @@ async def test_providers_probes_when_only_chunker_uses_docling_serve(
     from haiku.rag.ingester.api.routes import providers as providers_mod
     from haiku.rag.ingester.api.schemas import ProviderEndpoint
 
-    async def _fake_probe(client, base_url):
+    async def _fake_probe(_client, base_url):
         return ProviderEndpoint(base_url=base_url, reachable=True, status_code=200)
 
     monkeypatch.setattr(providers_mod, "_probe", _fake_probe)

tests/ingester/test_queue.py

@@ -530,6 +530,31 @@ async def test_retry_refuses_claimed_job(jobs):
     assert refreshed.attempts == 1
 
 
+@pytest.mark.asyncio
+async def test_retry_returns_live_sibling_instead_of_colliding(jobs):
+    """Retrying a dead job when a live job already exists for the same
+    (source_id, uri) is idempotent: it returns the live sibling rather than
+    violating uq_jobs_live (which previously surfaced as a 500)."""
+    first = await jobs.enqueue("s", "u", JobOp.UPSERT)
+    assert first is not None
+    claimed = await jobs.claim_next("w")
+    assert claimed is not None
+    await jobs.mark_dead(claimed.id, "boom", "w")
+
+    # A fresh live job for the same (source, uri) — e.g. re-discovered by a sweep.
+    live = await jobs.enqueue("s", "u", JobOp.UPSERT)
+    assert live is not None
+    assert live.id != first.id
+
+    result = await jobs.retry(first.id)
+    assert result.id == live.id
+    assert result.status is JobStatus.QUEUED
+    # The originally-dead row stays dead — not duplicated into a second live job.
+    refreshed = await jobs.get_job(first.id)
+    assert refreshed is not None
+    assert refreshed.status is JobStatus.DEAD
+
+
 @pytest.mark.asyncio
 async def test_retry_refuses_succeeded_job(jobs):
     """Succeeded rows should be re-ingested through the UPSERT path, not