feat(database): enhance podcast lifecycle management by adding temporary unpublishing during migration

surfsense_backend/app/zero_publication.py

@@ -100,12 +100,32 @@ def _column_exists(conn: Connection, table: str, column: str) -> bool:
     )
 
 
-def _expected_columns(conn: Connection, table: str) -> list[str] | None:
+def _table_exists(conn: Connection, table: str) -> bool:
+    return (
+        conn.execute(
+            text(
+                "SELECT 1 FROM information_schema.tables "
+                "WHERE table_schema = current_schema() "
+                "AND table_name = :table"
+            ),
+            {"table": table},
+        ).fetchone()
+        is not None
+    )
+
+
+def _expected_columns(
+    conn: Connection, table: str, *, include_missing_columns: bool = True
+) -> list[str] | None:
     columns = ZERO_PUBLICATION[table]
     if columns is None:
         return None
 
-    expected = list(columns)
+    if include_missing_columns:
+        expected = list(columns)
+    else:
+        expected = [column for column in columns if _column_exists(conn, table, column)]
+
     if table in {"documents", "user", "podcasts"} and _column_exists(
         conn, table, "_0_version"
     ):
@@ -113,11 +133,20 @@ def _expected_columns(conn: Connection, table: str) -> list[str] | None:
     return expected
 
 
-def _format_table_entry(conn: Connection, table: str) -> str:
-    columns = _expected_columns(conn, table)
+def _format_table_entry(
+    conn: Connection, table: str, *, include_missing_columns: bool = True
+) -> str | None:
+    if not include_missing_columns and not _table_exists(conn, table):
+        return None
+
+    columns = _expected_columns(
+        conn, table, include_missing_columns=include_missing_columns
+    )
     table_sql = _quote_identifier(table)
     if columns is None:
         return table_sql
+    if not include_missing_columns and not columns:
+        return None
 
     column_sql = ", ".join(_quote_identifier(column) for column in columns)
     return f"{table_sql} ({column_sql})"
@@ -126,9 +155,17 @@ def _format_table_entry(conn: Connection, table: str) -> str:
 def build_set_table_sql(conn: Connection) -> str:
     """Build the canonical plain SET TABLE statement for Zero's event triggers."""
 
-    table_list = ", ".join(
-        _format_table_entry(conn, table) for table in ZERO_PUBLICATION
-    )
+    table_entries = [
+        entry
+        for table in ZERO_PUBLICATION
+        if (
+            entry := _format_table_entry(
+                conn, table, include_missing_columns=False
+            )
+        )
+        is not None
+    ]
+    table_list = ", ".join(table_entries)
     return f"ALTER PUBLICATION {_quote_identifier(PUBLICATION_NAME)} SET TABLE {table_list}"