fix: auto add error message column

Author: luisggc

CHANGELOG.md

@@ -7,7 +7,7 @@ All notable changes to this project will be documented in this file.
 ### Added
 - Optional flags to continue deploying remaining scripts after an error, recording full error messages in the change history table and listing failed scripts at completion.
 ### Fixed
-- Preserve original script errors when the change history table lacks the `ERROR_MESSAGE` column
+- Automatically add missing `ERROR_MESSAGE` column to the change history table to capture full script errors
 
 ## [4.0.1] - 2025-02-17
 ### Changed

schemachange/session/SnowflakeSession.py

@@ -362,38 +362,21 @@ def apply_change_script(
                 CURRENT_TIMESTAMP
             );
         """
+        dedent_query = dedent(query)
         try:
-            self.execute_snowflake_query(dedent(query), logger=logger)
+            self.execute_snowflake_query(dedent_query, logger=logger)
         except snowflake.connector.errors.ProgrammingError as e:
             if "ERROR_MESSAGE" in str(e):
                 logger.warning(
-                    "Change history table missing ERROR_MESSAGE column, inserting without",
+                    "Change history table missing ERROR_MESSAGE column, adding column",
                     error=str(e),
                 )
-                fallback = f"""\
-                    INSERT INTO {self.change_history_table.fully_qualified} (
-                        VERSION,
-                        DESCRIPTION,
-                        SCRIPT,
-                        SCRIPT_TYPE,
-                        CHECKSUM,
-                        EXECUTION_TIME,
-                        STATUS,
-                        INSTALLED_BY,
-                        INSTALLED_ON
-                    ) VALUES (
-                        '{script_version}',
-                        '{script.description}',
-                        '{script.name}',
-                        '{script.type}',
-                        '{checksum}',
-                        {execution_time},
-                        '{status}',
-                        '{self.user}',
-                        CURRENT_TIMESTAMP
-                    );
-                """
-                self.execute_snowflake_query(dedent(fallback), logger=logger)
+                alter_query = (
+                    f"ALTER TABLE {self.change_history_table.fully_qualified} "
+                    "ADD COLUMN IF NOT EXISTS ERROR_MESSAGE VARCHAR"
+                )
+                self.execute_snowflake_query(alter_query, logger=logger)
+                self.execute_snowflake_query(dedent_query, logger=logger)
             else:
                 raise
         if status != "Success":

tests/session/test_SnowflakeSession.py

@@ -79,6 +79,7 @@ def test_apply_change_script_missing_error_message_column(
                 Exception("boom"),
                 ProgrammingError("invalid identifier 'ERROR_MESSAGE'", 0, 0),
                 None,
+                None,
             ]
         )
         with (
@@ -87,8 +88,12 @@ def test_apply_change_script_missing_error_message_column(
             pytest.raises(Exception),
         ):
             session.apply_change_script(script, "select 1", False, session.logger)
-        assert session.execute_snowflake_query.call_count == 3
+        assert session.execute_snowflake_query.call_count == 4
         first_insert = session.execute_snowflake_query.call_args_list[1].args[0]
-        fallback_insert = session.execute_snowflake_query.call_args_list[2].args[0]
+        alter_stmt = session.execute_snowflake_query.call_args_list[2].args[0]
+        retry_insert = session.execute_snowflake_query.call_args_list[3].args[0]
         assert "ERROR_MESSAGE" in first_insert
-        assert "ERROR_MESSAGE" not in fallback_insert
+        assert "ALTER TABLE" in alter_stmt
+        assert "ADD COLUMN" in alter_stmt
+        assert "ERROR_MESSAGE" in alter_stmt
+        assert "ERROR_MESSAGE" in retry_insert