script: strip comments in SQL statements

Regular expression does not match correctly against statements that contain
comments at their start. So strip those comments first (and whitespaces, while
we are at it).

Change-Id: Iad9b544bf995374d76cab1e125658aae2f8511f4
Closes-Bug: #1410494

migrate/tests/versioning/test_script.py

@@ -281,6 +281,16 @@ class TestSqlScript(fixture.Pathed, fixture.DB):
         for script_pattern in (
             "BEGIN TRANSACTION; %s; COMMIT;",
             "BEGIN; %s; END TRANSACTION;",
+            "/* comment */BEGIN TRANSACTION; %s; /* comment */COMMIT;",
+            "/* comment */ BEGIN TRANSACTION; %s; /* comment */ COMMIT;",
+            """
+-- comment
+BEGIN TRANSACTION;
+
+%s;
+
+-- comment
+COMMIT;""",
         ):
 
             test_statement = ("CREATE TABLE TEST1 (field1 int); "

migrate/versioning/script/sql.py

@@ -54,6 +54,7 @@ class SqlScript(base.BaseScript):
                 # not all drivers reliably handle multistatement queries or
                 # commands passed to .execute(), so split them and execute one
                 # by one
+                text = sqlparse.format(text, strip_comments=True, strip_whitespace=True)
                 for statement in sqlparse.split(text):
                     if statement:
                         if re.match(ignored_regex, statement):