* internal/perms: Fix grant parser bugs
This fixes two bugs in the grant parser:
1. The parser would accept "," as an output field when parsing from JSON.
This would then make it into the canonical string,
which would make it look like we had a trailing comma.
Disallow the use of a comma as an output field.
2. The parser would accept empty IDs when parsing from JSON.
Make this behavior consistent with the text behavior.
* internal/perms: also handle empty IDs in text form
* internal/perms: disallow any commas
Commas anywhere in ids or output fields corrupt
the canonical output string.
* internal/perms: disallow any reserved characters
id, ids and actions could all contain one of the
reserved characters ",", "=" or ";" when used with
JSON.
* testing(perms): Add Parse fuzz test
I ran this for a few minutes and it didn't discover anything catastrophic.
* Add roundtrip tests
* Fix invalid unicode parsing, empty output fields
* Do the unicode conversion once on input
* Remove incorrect fix for empty output fields
* Allow empty output_fields
This is the same behavior as output_fields=,
* Add tests back, make JSON behaviour consistent
* Rework the output fields mechanism to fix some bugs such as properly handling no fields
* Change signature of Fields
Co-authored-by: Jeff Mitchell <jeffrey.mitchell@gmail.com>