fix(tests): read column values not stale ORM entities after Core-DML merge (MissingGreenlet)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/test_tag_merge.py

@@ -281,13 +281,15 @@ async def test_merge_repoints_existing_aliases(db):
     )
     await db.flush()
     await svc.merge(a.id, b.id)
-    db.expire_all()  # merge() uses Core DML; drop stale identity-map state
-    al = (
-        await db.execute(
-            select(TagAlias).where(TagAlias.alias_string == "oldpred")
+    # Read the column value, not the entity: merge() uses Core DML, so an
+    # ORM instance would be stale and a lazy reload here would emit sync IO
+    # outside the async greenlet (MissingGreenlet).
+    cid = await db.scalar(
+        select(TagAlias.canonical_tag_id).where(
+            TagAlias.alias_string == "oldpred"
         )
-    ).scalar_one()
-    assert al.canonical_tag_id == b.id
+    )
+    assert cid == b.id
 
 
 @pytest.mark.asyncio
@@ -299,9 +301,8 @@ async def test_merge_fandom_reparents_children(db):
         "ChildChar", TagKind.character, fandom_id=f_src.id
     )
     await svc.merge(f_src.id, f_tgt.id)
-    db.expire_all()  # merge() uses Core DML; drop stale identity-map state
-    refreshed = await db.get(Tag, child.id)
-    assert refreshed.fandom_id == f_tgt.id
+    fid = await db.scalar(select(Tag.fandom_id).where(Tag.id == child.id))
+    assert fid == f_tgt.id
 
 
 @pytest.mark.asyncio
@@ -341,8 +342,15 @@ async def test_alias_per_observed_prediction_category(db):
     await db.flush()
     result = await svc.merge(a.id, b.id)
     assert result.alias_created is True
-    db.expire_all()
-    rows = (await db.execute(select(TagAlias))).scalars().all()
+    rows = (
+        await db.execute(
+            select(
+                TagAlias.alias_string,
+                TagAlias.alias_category,
+                TagAlias.canonical_tag_id,
+            )
+        )
+    ).all()
     assert {(r.alias_string, r.alias_category) for r in rows} == {
         ("predname", "general"),
         ("predname", "copyright"),
@@ -361,14 +369,15 @@ async def test_alias_fallback_to_kind_when_no_predictions(db):
     await db.flush()
     result = await svc.merge(a.id, b.id)
     assert result.alias_created is True
-    db.expire_all()
-    al = (
+    row = (
         await db.execute(
-            select(TagAlias).where(TagAlias.alias_string == "AllowNoPred")
+            select(
+                TagAlias.alias_category, TagAlias.canonical_tag_id
+            ).where(TagAlias.alias_string == "AllowNoPred")
         )
-    ).scalar_one()
-    assert al.alias_category == "character"
-    assert al.canonical_tag_id == b.id
+    ).one()
+    assert row.alias_category == "character"
+    assert row.canonical_tag_id == b.id
 
 
 @pytest.mark.asyncio
@@ -395,10 +404,9 @@ async def test_alias_create_does_not_clobber_existing(db):
     }
     await db.flush()
     await svc.merge(a.id, b.id)
-    db.expire_all()
-    al = (
-        await db.execute(
-            select(TagAlias).where(TagAlias.alias_string == "dupalias")
+    cid = await db.scalar(
+        select(TagAlias.canonical_tag_id).where(
+            TagAlias.alias_string == "dupalias"
         )
-    ).scalar_one()
-    assert al.canonical_tag_id == other.id  # pre-existing alias untouched
+    )
+    assert cid == other.id  # pre-existing alias untouched