[PYTHON-3036] Improve error message for unknown MongoClient options

doc/contributors.rst

@@ -98,3 +98,4 @@ The following is a list of people who have contributed to
 - Dainis Gorbunovs (DainisGorbunovs)
 - Iris Ho (sleepyStick)
 - Stephan Hof (stephan-hof)
+- Casey Clements (caseyclements)

pymongo/common.py

@@ -20,6 +20,7 @@
 import inspect
 import warnings
 from collections import OrderedDict, abc
+from difflib import get_close_matches
 from typing import (
  TYPE_CHECKING,
  Any,
@@ -162,9 +163,12 @@ def clean_node(node: str) -> tuple[str, int]:
  return host.lower(), port
 
 
-def raise_config_error(key: str, dummy: Any) -> NoReturn:
+def raise_config_error(key: str, suggestions: Optional[list] = None) -> NoReturn:
  """Raise ConfigurationError with the given key name."""
- raise ConfigurationError(f"Unknown option {key}")
+ msg = f"Unknown option: {key}."
+ if suggestions:
+ msg += f" Did you mean one of ({', '.join(suggestions)}) or maybe a camelCase version of one? Refer to docstring."
+ raise ConfigurationError(msg)
 
 
 # Mapping of URI uuid representation options to valid subtypes.
@@ -788,8 +792,8 @@ def validate_server_monitoring_mode(option: str, value: str) -> str:
  if alias not in URI_OPTIONS_VALIDATOR_MAP:
  URI_OPTIONS_VALIDATOR_MAP[alias] = URI_OPTIONS_VALIDATOR_MAP[optname]
 
-# Map containing all URI option and keyword argument validators.
-VALIDATORS: dict[str, Callable[[Any, Any], Any]] = URI_OPTIONS_VALIDATOR_MAP.copy()
+ # Map containing all URI option and keyword argument validators.
+ VALIDATORS: dict[str, Callable[[Any, Any], Any]] = URI_OPTIONS_VALIDATOR_MAP.copy()
 VALIDATORS.update(KW_VALIDATORS)
 
 # List of timeout-related options.
@@ -817,7 +821,11 @@ def validate_auth_option(option: str, value: Any) -> tuple[str, Any]:
 def validate(option: str, value: Any) -> tuple[str, Any]:
  """Generic validation function."""
  lower = option.lower()
- validator = VALIDATORS.get(lower, raise_config_error)
+ try:
+ validator = VALIDATORS[lower]
+ except KeyError:
+ suggestions = get_close_matches(lower, VALIDATORS, cutoff=0.2)
+ raise_config_error(option, suggestions)
  value = validator(option, value)
  return option, value
 
@@ -856,7 +864,11 @@ def get_setter_key(x: str) -> str:
  for opt, value in options.items():
  normed_key = get_normed_key(opt)
  try:
- validator = URI_OPTIONS_VALIDATOR_MAP.get(normed_key, raise_config_error)
+ try:
+ validator = URI_OPTIONS_VALIDATOR_MAP[normed_key]
+ except KeyError:
+ suggestions = get_close_matches(normed_key, URI_OPTIONS_VALIDATOR_MAP, cutoff=0.2)
+ raise_config_error(opt, suggestions)
  value = validator(opt, value) # noqa: PLW2901
  except (ValueError, TypeError, ConfigurationError) as exc:
  if warn:

test/test_client.py

@@ -535,6 +535,16 @@ def test_client_options(self):
  self.assertIsInstance(c.options.retry_writes, bool)
  self.assertIsInstance(c.options.retry_reads, bool)
 
+ def test_validate_suggestion(self):
+ """Validate kwargs in constructor."""
+ self.assertRaises(ConfigurationError, MongoClient, auth="standard")
+
+ try:
+ MongoClient(auth="standard")
+ except ConfigurationError as exc:
+ expected = "Unknown option: auth. Did you mean one of (authsource, authmechanism, authoidcallowedhosts) or maybe a camelCase version of one? Refer to docstring."
+ self.assertEqual(exc.args[0], expected)
+
 
 class TestClient(IntegrationTest):
  def test_multiple_uris(self):

test/test_uri_parser.py

@@ -144,6 +144,13 @@ def test_split_options(self):
  self.assertEqual({"authsource": "foobar"}, split_options("authSource=foobar"))
  self.assertEqual({"maxpoolsize": 50}, split_options("maxpoolsize=50"))
 
+ # Test suggestions given when invalid kwarg passed
+ try:
+ split_options("auth=GSSAPI")
+ except ConfigurationError as exc:
+ expected = "Unknown option: auth. Did you mean one of (authsource, authmechanism, timeoutms) or maybe a camelCase version of one? Refer to docstring."
+ self.assertEqual(exc.args[0], expected)
+
  def test_parse_uri(self):
  self.assertRaises(InvalidURI, parse_uri, "http://foobar.com")
  self.assertRaises(InvalidURI, parse_uri, "http://foo@foobar.com")