Add Postgresql warning when using CREATE INDEX without CONCURRENTLY keyword

django_migration_linter/sql_analyser/analyser.py

@@ -29,4 +29,4 @@ def analyse_sql_statements(
 ):
     sql_analyser = get_sql_analyser(database_vendor, exclude_migration_tests)
     sql_analyser.analyse(sql_statements)
-    return sql_analyser.errors, sql_analyser.ignored
+    return sql_analyser.errors, sql_analyser.ignored, sql_analyser.warnings

django_migration_linter/sql_analyser/postgresql.py

@@ -1,5 +1,16 @@
+import re
+
 from .base import BaseAnalyser
 
 
 class PostgresqlAnalyser(BaseAnalyser):
-    migration_tests = []
+    migration_tests = [
+        {
+            "code": "CREATE_INDEX",
+            "fn": lambda sql, **kw: re.search("CREATE (UNIQUE )?INDEX", sql)
+            and not re.search("INDEX CONCURRENTLY", sql),
+            "msg": "CREATE INDEX locks table",
+            "mode": "one_liner",
+            "type": "warning",
+        },
+    ]