Edge case where RON fails but all other serde format types succeed

[jaynus]

Using any format of bitflags serialization, I seem to have found, somehow, a way in which RON fails to deserialize values, but all other serde serializers seem to handle just fine. I don't understand serde enough to understand what is incorrect about the RON implementation.

Error is: thread 'main' panicked at 'called Result::unwrap() on an Err value: Message("invalid type: string "One", expected a borrowed string")', src/libcore/result.rs:997:5

Specifically, I could at least trace the error down to this line: https://github.com/kvark/bitflags-serial/blob/master/src/lib.rs#L66
or this line
https://github.com/H2CO3/option_set/blob/master/src/lib.rs#L242

I've created a repo minimally showing the issue here: https://github.com/jaynus/ron_fail_poc

I ran into this using RON originally with bitflags_serial (https://github.com/kvark/bitflags-serial). I then swapped to option_set in an attempt to fix it, and ran into the same issue.

[kvark]

Any idea how does this differ from a general case that is expected to work with RON?

[jaynus]

How do you mean exactly? I've updated the test case showing working cases vs. non-working cases with bitflags vs. option_set. The update shows that bitflags works for both ron and serde_json, while option_set works with serde_json but NOT ron.

I'm not sure what details you need.

Update here:
jaynus/ron_fail_poc@fe5bb3d

[kvark]

Hm weird. I mean, the bitflags-serial was specifically implemented with Ron in mind and tested on it, see bitflags/bitflags#147
So the fact it no longer works means there was a regression in one of the pieces.

[jaynus]

Oh! I totally failed to connect the dots that that was you! I've added bitflags_serial to the test case.

I've added a test case for bitflags_serial, which also appears to fail for JSON and RON.

jaynus/ron_fail_poc@faa4ce5

Test Output Is:
! RON option_set FAILED!
! JSON bitflags_serial FAILED!
! RON bitflags_serial FAILED!

[jaynus]

As an additional, I've noticed there are cases where it DOES work with amethyst assets RonFormat loader, though.

So it appears maybe its a difference between from_str and from_bytes? I cannot replicate from_bytes working though in my case.

[jaynus]

Update: I've also confirmed it fails with stable (I am using latest nightly).

[jaynus]

As referenced in that PR to bitflags-serial, I'm not sure if this is a bug in bitflags-serial or RON. it appears to be because of the call to the unimplemented visit_str, instead of the originally implemented visit_bytes. But I don't know serde or RON well enough though to say why this is the case.

[juntyr]

Fixed with #352