fix(migration-0022): pre-DELETE colliding image_provenance rows before the UPDATE post_id — same row-by-row UNIQUE pattern as the post-collision case, just one level deeper. When image X has provenance under both keep and drop, UPDATE drop→keep would fire uq_image_provenance_image_post on the row that'd collide with the existing (X, keep). Pre-delete those rows (their info is already represented by the keep-side provenance) before the UPDATE moves the rest.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-26 18:05:49 -04:00
parent eee107766e
commit f3e8f30a8f
1 changed files with 19 additions and 9 deletions
@@ -120,6 +120,25 @@ def upgrade() -> None:
                keep_id = posts[0][0]  # already sorted by id ASC
            drop_ids = [p[0] for p in posts if p[0] != keep_id]
            for drop_id in drop_ids:
+                # Pre-delete image_provenance rows under drop_ whose
+                # image_record_id ALREADY has a provenance under keep —
+                # the UPDATE below would otherwise repoint them and
+                # trip uq_image_provenance_image_post (alembic 0021)
+                # row-by-row before any after-the-fact dedupe could
+                # run. Operator's v26.05.26.3 deploy 2026-05-26 tripped
+                # this at line 123.
+                conn.execute(
+                    text("""
+                        DELETE FROM image_provenance
+                        WHERE post_id = :drop_
+                          AND image_record_id IN (
+                              SELECT image_record_id FROM image_provenance
+                              WHERE post_id = :keep
+                          )
+                    """),
+                    {"keep": keep_id, "drop_": drop_id},
+                )
+                # Now safe to repoint the survivors.
                conn.execute(
                    text("""
                        UPDATE image_provenance SET post_id = :keep
@@ -134,15 +153,6 @@ def upgrade() -> None:
                    """),
                    {"keep": keep_id, "drop_": drop_id},
                )
-                # Repointed provenance may now collide on
-                # uq_image_provenance_image_post (alembic 0021). Dedupe.
-                conn.execute(text("""
-                    DELETE FROM image_provenance ip1
-                    USING image_provenance ip2
-                    WHERE ip1.image_record_id = ip2.image_record_id
-                      AND ip1.post_id = ip2.post_id
-                      AND ip1.id > ip2.id
-                """))
                conn.execute(
                    text("DELETE FROM post WHERE id = :drop_"),
                    {"drop_": drop_id},