fix(cli): handle invalid JSON input in CLI options gracefully

amimas · JohnVillalovos · commit 9c348a30c9a8 · 2026-03-23T07:13:08.000-07:00
Previously, providing malformed JSON to CLI options (such as `--strategies`)
resulted in a raw Python traceback (`JSONDecodeError`) surfacing to the user.
Additionally, whitespace-only input was implicitly converted to `None`,
causing the CLI to send `null` in the API request body, which could be
rejected by the GitLab API.

This change updates `JsonAttribute` to:
- Catch `ValueError` and `TypeError` during JSON parsing.
- Raise a `GitlabParsingError`, which the CLI catches to display a
  user-friendly error message.
- Treat whitespace-only strings as invalid JSON rather than `None`,
  requiring the user to be explicit (e.g. passing `'[]'` or `'{}'`).

Tests have been updated to verify the new error handling behavior.
diff --git a/gitlab/types.py b/gitlab/types.py
@@ -4,6 +4,8 @@
 import json
 from typing import Any, TYPE_CHECKING
 
+from gitlab import exceptions
+
 
 @dataclasses.dataclass(frozen=True)
 class RequiredOptional:
@@ -59,10 +61,12 @@ def get_for_api(self, *, key: str) -> tuple[str, Any]:
 
 class JsonAttribute(GitlabAttribute):
     def set_from_cli(self, cli_value: str) -> None:
-        if not cli_value.strip():
-            self._value = None
-        else:
+        try:
             self._value = json.loads(cli_value)
+        except (ValueError, TypeError) as e:
+            raise exceptions.GitlabParsingError(
+                f"Could not parse JSON data: {e}"
+            ) from e
 
 
 class _ListArrayAttribute(GitlabAttribute):
diff --git a/tests/functional/cli/test_cli_project_feature_flags.py b/tests/functional/cli/test_cli_project_feature_flags.py
@@ -141,3 +141,22 @@ def test_project_feature_flag_cli_update(gitlab_cli, project, feature_flag_cli):
     assert ret.success
     data = json.loads(ret.stdout)
     assert data["active"] is False
+
+
+def test_project_feature_flag_cli_create_with_malformed_strategies(gitlab_cli, project):
+    flag_name = "test_flag_cli_malformed_strategies"
+    strategies_json = '[{"name": "userWithId"'  # Malformed JSON
+
+    cmd = [
+        "project-feature-flag",
+        "create",
+        "--project-id",
+        str(project.id),
+        "--name",
+        flag_name,
+        "--strategies",
+        strategies_json,
+    ]
+    ret = gitlab_cli(cmd)
+    assert not ret.success
+    assert "Could not parse JSON data" in ret.stderr
diff --git a/tests/unit/test_types.py b/tests/unit/test_types.py
@@ -1,6 +1,6 @@
 import pytest
 
-from gitlab import types
+from gitlab import exceptions, types
 
 
 class TestRequiredOptional:
@@ -131,8 +131,8 @@ def test_json_attribute() -> None:
     attr.set_from_cli('{"key": "value"}')
     assert attr.get() == {"key": "value"}
 
-    attr.set_from_cli("  ")
-    assert attr.get() is None
+    with pytest.raises(exceptions.GitlabParsingError):
+        attr.set_from_cli("  ")
 
 
 # CommaSeparatedStringAttribute tests
