Traceback in SQL Commenter when an empty string is encountered

[selcuk]

Describe your environment

OS: Debian, macOS
Python version: Python 3.12
Package version: 0.51b2
Django version: 5.1.6

What happened?

In some cases (in my case when psycopg3 connection pooling is enabled in a Django project) the SQL statement may be an empty string, which causes a traceback in the sqlcommenter.

Steps to Reproduce

• Set up a Django project with psycopg3 connection pool support (https://docs.djangoproject.com/en/5.1/ref/databases/#connection-pool)
• Enable OpenTelemetry (opentelemetry-instrumentation-django, opentelemetry-instrumentation-dbapi, opentelemetry-instrumentation-psycopg)
• Perform any database related operation.

Expected Result

No traceback.

Actual Result

Getting a traceback:

[2025-02-28 04:37:32,454] [__init__] [ERROR]: "Exception while generating sql comment: string index out of range"
Traceback (most recent call last):
  File "/Users/selcuk/src/testapp/.venv/lib/python3.12/site-packages/opentelemetry/instrumentation/dbapi/__init__.py", line 505, in _update_args_with_added_sql_comment
    statement = _add_sql_comment(args_list[0], **commenter_data)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/selcuk/src/testapp/.venv/lib/python3.12/site-packages/opentelemetry/instrumentation/sqlcommenter_utils.py", line 26, in _add_sql_comment
    if sql[-1] == ";":
       ~~~^^^^
IndexError: string index out of range

Additional context

No response

Would you like to implement a fix?

Yes