tests: Handle DDL command in cur.sql() differently (#785)

For ease of programming we have a `cur.sql()` method that can be used to
execute any sql command. Fetching rows for DDL statements doesn't work
though, so we were catching that error and ignoring it. [In psycopg
3.2.8 the exact error message was changed][1].

Instead of detecting the new error message, this change makes sure that
we don't trigger this error at all. This is done by detecting whether
our result has rows, before calling `fetchall()`.

Originally reported @Alphaxxxxx in
#784 (comment)

[1]: psycopg/psycopg@1eb7e5a

Author: JelteF

test/pycheck/utils.py

@@ -312,13 +312,12 @@ def __getattr__(self, name):
 
     def sql(self, query, params=None, **kwargs) -> Any:
         self.execute(query, params, **kwargs)
-        try:
-            return simplify_query_results(self.fetchall())
-        except psycopg.ProgrammingError as e:
-            if "the last operation didn't produce a result" == str(e):
-                # This happens when the query is a DDL statement
-                return NoResult
-            raise
+        if self.pgresult and self.pgresult.status == psycopg.pq.ExecStatus.COMMAND_OK:
+            # This happens when the query is a DDL statement. Calling fetchall
+            # would fail with a ProgrammingError in that case.
+            return NoResult
+
+        return simplify_query_results(self.fetchall())
 
     def dsql(self, query, **kwargs):
         """Run a DuckDB query using duckdb.query()"""
@@ -365,13 +364,12 @@ def sql(self, query, params=None, **kwargs):
 
     async def sql_coroutine(self, query, params=None, **kwargs) -> Any:
         await self.execute(query, params, **kwargs)
-        try:
-            return simplify_query_results(await self.fetchall())
-        except psycopg.ProgrammingError as e:
-            if "the last operation didn't produce a result" == str(e):
-                # This happens when the query is a DDL statement
-                return NoResult
-            raise
+        if self.pgresult and self.pgresult.status == psycopg.pq.ExecStatus.COMMAND_OK:
+            # This happens when the query is a DDL statement. Calling fetchall
+            # would fail with a ProgrammingError in that case.
+            return NoResult
+
+        return simplify_query_results(await self.fetchall())
 
     def dsql(self, query, **kwargs):
         """Run a DuckDB query using duckdb.query()"""