ai: apply changes for #914 (1 review thread)

Addresses:
  - #3799812091 at src/databricks/sql/backend/kernel/auth_bridge.py:258

Signed-off-by: peco-engineer-bot[bot] <peco-engineer-bot[bot]@users.noreply.github.com>

Author: peco-engineer-bot[bot]

src/databricks/sql/backend/kernel/auth_bridge.py

@@ -273,7 +273,7 @@ def kernel_auth_kwargs(
             "auth_type": "oauth-u2m",
             "client_id": client_id or PYSQL_OAUTH_CLIENT_ID,
             "redirect_port": (
-                int(redirect_port)
+                _coerce_redirect_port(redirect_port)
                 if client_id and redirect_port is not None
                 else PYSQL_OAUTH_REDIRECT_PORT_RANGE[0]
             ),
@@ -312,6 +312,23 @@ def kernel_auth_kwargs(
     )
 
 
+def _coerce_redirect_port(redirect_port: Any) -> int:
+    """Coerce an ``oauth_redirect_port`` value (which may arrive as a string,
+    e.g. from a DSN) to an int.
+
+    A non-numeric value is a caller error; surface it as a PEP 249
+    ``ProgrammingError`` (as ``_normalize_scopes`` does for malformed
+    ``oauth_scopes``) rather than a bare ``ValueError``, so callers get a
+    consistent, actionable exception type for garbled input."""
+    try:
+        return int(redirect_port)
+    except (TypeError, ValueError):
+        raise ProgrammingError(
+            f"oauth_redirect_port must be an integer (or a string parseable as "
+            f"one), got {redirect_port!r}."
+        )
+
+
 def _normalize_scopes(scopes: Any) -> Optional[list]:
     """Normalise an ``oauth_scopes`` value to a list of strings, or
     ``None`` to let the kernel apply its defaults.

tests/unit/test_kernel_auth_bridge.py

@@ -346,6 +346,21 @@ def test_u2m_redirect_port_coerced_to_int(self):
         assert kwargs["redirect_port"] == 8021
         assert isinstance(kwargs["redirect_port"], int)
 
+    def test_u2m_redirect_port_non_numeric_raises_programming_error(self):
+        # A garbled oauth_redirect_port is a caller error of the same class
+        # as a malformed oauth_scopes, so it must surface as a PEP 249
+        # ProgrammingError (not a bare ValueError from int()) for a
+        # consistent, actionable exception type.
+        with pytest.raises(ProgrammingError, match="oauth_redirect_port must be"):
+            kernel_auth_kwargs(
+                _FakeOAuthProvider(),
+                {
+                    "auth_type": "databricks-oauth",
+                    "oauth_client_id": "custom-client",
+                    "oauth_redirect_port": "not-a-port",
+                },
+            )
+
     def test_u2m_redirect_port_ignored_without_client_id(self):
         # A bare oauth_redirect_port (no explicit client_id) must NOT be
         # forwarded: it would be paired with the default databricks-sql-python