Better error in config. (Issue #270)

Author: erezsh

data_diff/config.py

@@ -36,7 +36,10 @@ def _apply_config(config: Dict[str, Any], run_name: str, kw: Dict[str, Any]):
 
  # Process databases + tables
  for index in "12":
- args = run_args.pop(index, {})
+ try:
+ args = run_args.pop(index)
+ except KeyError:
+ raise ConfigParseError(f"Could not find source #{index}: Expecting a key of '{index}' containing '.database' and '.table'.")
  for attr in ("database", "table"):
  if attr not in args:
  raise ConfigParseError(f"Running 'run.{run_name}': Connection #{index} is missing attribute '{attr}'.")