When parsing the module file, parse the JSON directly from the AST
node, because the AST node contains the line number of the schema
in the module and thus we can resolve the correct line number for
errors within the JSON. Convert the `JSONDecodeError` to a
`SyntaxError` which results in an overall better exception message:
Before:
Traceback (most recent call last):
File "/workspaces/osbuild/osbuild/meta.py", line 331, in get_schema
opts = self._make_options(version)
[...]
File "/usr/lib64/python3.9/json/decoder.py", line 353, in raw_decode
obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Expecting property name enclosed in
double quotes: line 2 column 1 (char 14)
After:
Traceback (most recent call last):
File "/usr/lib64/python3.9/runpy.py", line 197, in _run_module_as_main
return _run_code(code, main_globals, None,
[...]
raise SyntaxError(msg, detail) from None
File "stages/org.osbuild.ostree.init-fs", line 31
additionalProperties: False
^
SyntaxError: Invalid schema: Expecting property name enclosed in ...
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