The return value of json_sax::parse_error() was documented both as "must
return false" and as "whether the parsing should continue", and the code
just passed it on. For JSON text, parsing stopped anyway, but sax_parse()
could report success for invalid input. The binary readers read on after
the error, looping forever on a CBOR indefinite-length array without its
end.
Now false stops parsing, and true recovers from the error:
- JSON text is repaired with the smallest local edit (insert a missing
',' or ':', remove a stray token, keep the readable part of a broken
string or number, null for a value that cannot be read, close the
innermost container at a wrong closing bracket and all of them at the
end of the input), and parsing continues. The SAX events stay balanced,
every key is followed by exactly one value, and each token is reported
at most once.
- The binary formats cannot resynchronize, so they stop, but complete
the value read so far.
sax_parse() returns false after any error. parse(), accept(), and the
from_*() functions never recover and compile to the same code as before.
Supersedes #4522.
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
9adb510a0d