jsonpb: improve error reporting

[mwitkow]

This PR addresses the issue of:
#266

See the added test for the modification in error handling

[dsnet]

Adding error diagnostics sounds fine, but there is no reason to export the error type. Please unexport that.

[mwitkow]

I've rebased on latest master, and made the error struct private. @dsnet can you PTAL?

CC @io-ben @Helcaraxan

[dsnet]

Hi, thanks for working on this. Apologies for the long delay in reviewing. Can you actually rebase against the dev branch?

[mwitkow]

@dsnet done, it's now against dev. had to rewrite a bunch of commits.

[dsnet]

There are some test failures, fix?

[mwitkow]

😕

--- FAIL: TestUnmarshalReturnsUsefulErrors (0.00s)
	jsonpb_test.go:1210: in UnknownFieldErrors expected error 
		'unparsable field Simple: fields [unknownOne unknownTwo] do not exist in set of known fields [oBool oInt32 oInt64 oUint32 oUint64 oSint32 oSint64 oFloat oDouble oString oBytes]'
		 but got 
		'unparsable field Simple: fields [unknownTwo unknownOne] do not exist in set of known fields [oBool oInt32 oInt64 oUint32 oUint64 oSint32 oSint64 oFloat oDouble oString oBytes]'
FAIL
FAIL	github.com/golang/protobuf/jsonpb	0.028s

and that's on the 1.x run, which is using 1.10, while the 1.10.x test test run worked. Looks like a flake
How do I retrigger this run?

[healiha]

Would be great if we could finally have this improvement. You could --amend --no-edit your commit and force push to trigger a new build, although I'm not sure that's the best way to do it.

cc @dsnet

[base698]

Could also revert, then revert the revert and squash it. I really need this feature as well...

[mwitkow]

rebased on top of latest dev and force pushed. Let's hope the Travis gods are benign ;)

[spenczar]

I'm interested in reviving this. @mwitkow, what's the status here? I can jump in.

[dsnet]

jsonpb has been completely re-written in v2, so all of this is probably moot.

See https://github.com/golang/protobuf/tree/api-v2/encoding/protojson

If the errors produced by v2 are still insufficient, it'd be good to improve the errors there.

[spenczar]

I haven't looked at the v2 errors yet, I'm not sure. I just got here from twitchtv/twirp#148, through #266.

Is there a master issue for v2, or a targeted release date that I can track against?

[dsnet]

The closest thing to a "master" issue is #364, which was the primary reason for a v2.

There is no official release date, but we've been aspirationally trying to target a release by GopherCon 2019 (i.e., end of July). I say aspirational because there's still a number items to address.

[dsnet]

Closing as this is unlikely relevant in light of the v2 re-write.