Failed to get ID token from Auth0 due to "untagged enum Timestamp"

[jmmv]

Hello,

I'm trying to use this crate (version 2.5.0) against Auth0 and I'm running into some issues. It's possible that this is caused by me misusing the crate's API, but... the code I have so far is a direct copy/paste of the sample code in the documentation, so there may be an actual bug.

When I issue the exchange_code call to obtain an ID token right after I get a callback redirect, I get an error of type RequestTokenError::Parse. Here is the error message (first field of the Parse type):

Error { path: Path { segments: [] }, original: Error(\"Failed to parse payload JSON: Error(\\\"data did not match any variant of untagged enum Timestamp\\\", line: 1, column: 466)\", line: 1, column: 1626) }

And then this is the content (second field of the Parse type) I got back from the server (tokens redacted):

{\"access_token\":\"some secret stuff\",\"id_token\":\"more secret stuff\",\"scope\":\"openid profile\",\"expires_in\":86401,\"token_type\":\"Bearer\"}"}

I suspect the problem is caused by the untyped expires_in field, but as far as I can tell, that's a valid reply from the server.

Note that I had to explicitly capture the Parse error and turn the raw byte output from the server into a string to print it out. (It'd be nice if the default Debug on Parse did this, as it was pretty annoying to decode the actual output I got from the server.)

Could you advice? Am I really misusing something, or does the code in the crate need some extra type annotations for proper deserialization?

Thank you!

[jmmv]

Looking further into this, the problem is coming from the content of the ID token itself. When decoding it via jwt.io, I get:

{
  "nickname": "jmmv",
  "name": "some@email.address",
  "picture": "gravatar URL",
  "updated_at": "2023-02-15T14:10:56.330Z",
  "iss": "https://dev-foobar.us.auth0.com/",
  "aud": "some value",
  "iat": 1676653285,
  "exp": 1676689285,
  "sub": "auth0|some value",
  "sid": "some value",
  "nonce": "ekkh3mqcD_NOZD2rpf7kFA"
}

and passing the base64-encoded token to CoreIdToken::from_str results into the same error...

[jmmv]

... and this is a dup of https://github.com/ramosbugs/openidconnect-rs/issues/23. Glad there is a feature to fix this!