db: fix orphan rows — cascade delete_site, wire up reconcile on startup

delete_site() leaked rows in tag_types, search_history, and
saved_searches; reconcile_library_meta() was implemented but never
called. Add tests for both fixes plus tag cache pruning.

booru_viewer/core/db.py

@@ -328,6 +328,9 @@ class Database:
 
     def delete_site(self, site_id: int) -> None:
         with self._write():
+            self.conn.execute("DELETE FROM tag_types WHERE site_id = ?", (site_id,))
+            self.conn.execute("DELETE FROM search_history WHERE site_id = ?", (site_id,))
+            self.conn.execute("DELETE FROM saved_searches WHERE site_id = ?", (site_id,))
             self.conn.execute("DELETE FROM favorites WHERE site_id = ?", (site_id,))
             self.conn.execute("DELETE FROM sites WHERE id = ?", (site_id,))
 

booru_viewer/gui/main_window.py

@@ -120,6 +120,11 @@ class BooruApp(QMainWindow):
         self._setup_ui()
         self._setup_menu()
         self._load_sites()
+        # One-shot orphan cleanup — must run after DB + library dir are
+        # configured, before the library tab is first populated.
+        orphans = self._db.reconcile_library_meta()
+        if orphans:
+            log.info("Reconciled %d orphan library_meta rows", orphans)
         # Debounced save for the main window state — fires from resizeEvent
         # (and from the splitter timer's flush on close). Uses the same
         # 300ms debounce pattern as the splitter saver.

tests/core/test_db.py

@@ -96,3 +96,117 @@ def test_get_bookmarks_like_escaping(tmp_db):
     results = tmp_db.get_bookmarks(search="cat_ear")
     tags_returned = {b.tags for b in results}
     assert tags_returned == {"cat_ear"}
+
+
+# -- delete_site cascading cleanup --
+
+def _seed_site(db, name, site_id_out=None):
+    """Create a site and populate all child tables for it."""
+    site = db.add_site(name, f"http://{name}.test", "danbooru")
+    db.add_bookmark(
+        site_id=site.id, post_id=1, file_url=f"http://{name}.test/1.jpg",
+        preview_url=None, tags="test",
+    )
+    db.add_search_history("test query", site_id=site.id)
+    db.add_saved_search("my search", "saved query", site_id=site.id)
+    db.set_tag_labels(site.id, {"artist:bob": "artist"})
+    return site
+
+
+def _count_rows(db, table, site_id, *, id_col="site_id"):
+    """Count rows in *table* belonging to *site_id*."""
+    return db.conn.execute(
+        f"SELECT COUNT(*) FROM {table} WHERE {id_col} = ?", (site_id,)
+    ).fetchone()[0]
+
+
+def test_delete_site_cascades_all_related_rows(tmp_db):
+    """Deleting a site must remove rows from all five related tables."""
+    site = _seed_site(tmp_db, "doomed")
+    tmp_db.delete_site(site.id)
+    assert _count_rows(tmp_db, "sites", site.id, id_col="id") == 0
+    assert _count_rows(tmp_db, "favorites", site.id) == 0
+    assert _count_rows(tmp_db, "tag_types", site.id) == 0
+    assert _count_rows(tmp_db, "search_history", site.id) == 0
+    assert _count_rows(tmp_db, "saved_searches", site.id) == 0
+
+
+def test_delete_site_does_not_affect_other_sites(tmp_db):
+    """Deleting site A must leave site B's rows in every table untouched."""
+    site_a = _seed_site(tmp_db, "site-a")
+    site_b = _seed_site(tmp_db, "site-b")
+
+    before = {
+        t: _count_rows(tmp_db, t, site_b.id, id_col="id" if t == "sites" else "site_id")
+        for t in ("sites", "favorites", "tag_types", "search_history", "saved_searches")
+    }
+
+    tmp_db.delete_site(site_a.id)
+
+    for table, expected in before.items():
+        id_col = "id" if table == "sites" else "site_id"
+        assert _count_rows(tmp_db, table, site_b.id, id_col=id_col) == expected, (
+            f"{table} rows for site B changed after deleting site A"
+        )
+
+
+# -- reconcile_library_meta --
+
+def test_reconcile_library_meta_removes_orphans(tmp_db, tmp_library):
+    """Rows whose files are missing on disk are deleted; present files kept."""
+    (tmp_library / "12345.jpg").write_bytes(b"\xff")
+    tmp_db.save_library_meta(post_id=12345, tags="test", filename="12345.jpg")
+    tmp_db.save_library_meta(post_id=99999, tags="orphan", filename="99999.jpg")
+
+    removed = tmp_db.reconcile_library_meta()
+
+    assert removed == 1
+    assert tmp_db.is_post_in_library(12345) is True
+    assert tmp_db.is_post_in_library(99999) is False
+
+
+def test_reconcile_library_meta_skips_empty_dir(tmp_db, tmp_library):
+    """An empty library dir signals a possible unmounted drive — refuse to
+    reconcile and leave orphan rows intact."""
+    tmp_db.save_library_meta(post_id=12345, tags="test", filename="12345.jpg")
+
+    removed = tmp_db.reconcile_library_meta()
+
+    assert removed == 0
+    assert tmp_db.is_post_in_library(12345) is True
+
+
+# -- tag cache pruning --
+
+def test_prune_tag_cache(tmp_db):
+    """After inserting more tags than the cap, only the newest entries survive."""
+    from booru_viewer.core.db import Database
+
+    original_cap = Database._TAG_CACHE_MAX_ROWS
+    try:
+        Database._TAG_CACHE_MAX_ROWS = 5
+
+        site = tmp_db.add_site("test", "http://test.test", "danbooru")
+
+        # Insert 8 rows with explicit, distinct fetched_at timestamps so
+        # pruning order is deterministic.
+        with tmp_db._write():
+            for i in range(8):
+                tmp_db.conn.execute(
+                    "INSERT OR REPLACE INTO tag_types "
+                    "(site_id, name, label, fetched_at) VALUES (?, ?, ?, ?)",
+                    (site.id, f"tag_{i}", "general", f"2025-01-01T00:00:{i:02d}Z"),
+                )
+            tmp_db._prune_tag_cache()
+
+        count = tmp_db.conn.execute("SELECT COUNT(*) FROM tag_types").fetchone()[0]
+        assert count == 5
+
+        surviving = {
+            r["name"]
+            for r in tmp_db.conn.execute("SELECT name FROM tag_types").fetchall()
+        }
+        # The 3 oldest (tag_0, tag_1, tag_2) should have been pruned
+        assert surviving == {"tag_3", "tag_4", "tag_5", "tag_6", "tag_7"}
+    finally:
+        Database._TAG_CACHE_MAX_ROWS = original_cap