Descriptive error for trailing comma in json file

[leok610]

I realize that check-jsonschema is not a linter, but the generic error message about failing to parse a file as JSON is not helpful.

I didn't check yet what you're using internally to load the JSON into Python, but the json.load() method has an informative error message that could be passed on to the user at the CLI:

JSON Error: Illegal trailing comma before end of array: line 10 column 18 (char 234)

Is this implementation feasible?

[sirosen]

Yeah, I'd be happy to look at a PR for this, or I can try to remember to circle back and do it.
This is particularly regarding the default message when non-verbose output is used.

It might be trivial or it might be a bit tricky. Off the top of my head, I can't remember enough detail to be certain. Each of the supported parsers may give back different flavors of errors, and we need to simply "look at them and pass that info back".

If you just want that data today, passing a single -v for verbose mode gets you a simplified traceback which would look something akin to

Several files failed to parse.
  FailedFileLoadError: Failed to parse tmp.json
    in "/blah-blah-path-to-source/check_jsonschema/instance_loader.py", line 50
    >>> data: t.Any = self._parsers.parse_data_with_path(

    caused by

    JSONDecodeError: Expecting value: line 1 column 4 (char 3)
    ... # blah blah more follows

Without the -v it's simply

Several files failed to parse.
  Failed to parse tmp.json

which is too terse.

I think the ideal, for non-verbose mode, would be something like

Several files failed to parse.
  Failed to parse tmp.json
    JSONDecodeError: Expecting value: line 1 column 4 (char 3)

It's not so much more information that we're overwhelming people.