When using DjangoDebugMiddleware, debug tracking presumes cursor.execute argument is a string, raising an error

• What is the current behavior?

When using the DjangoDebugMiddleware, Graphene Django wraps cursor.execute calls in a class that logs the query. Among the properties it logs is is_select, which attempts to guess if a query is a select query by looking for "select" in the argument to cursor.execute:

                "is_select": sql.lower().strip().startswith("select"),

When cursor.execute is called with a non-string argument, such as a psycopg2 query template, this raises an error:

from django.db import connection
from psycopg2 import sql

with connection.cursor() as cursor:
    query = sql.SQL("SELECT * FROM {table}").format(table=sql.Identifier("my_table"))
    cursor.execute(query)

This raises:

graphql.error.located_error.GraphQLLocatedError: 'Composed' object has no attribute 'lower'

• What is the expected behavior? Grahene Django should not presume that the argument to connection.cursor() will always be a string, and do appropriate string coercion as needed before calling string methods on it.

• What is the motivation / use case for changing the behavior? Robustness. It's ideal not to throw exceptions from normal uses of core Django methods which graphene-django monkeypatches.

• Please tell us about your environment:

  • Version: graphene-django 2.5.0
  • Platform: Ubuntu Linux 18.04, Django 2.2.12, graphene 2.1.8