RUST-713 Fix underflow on BSON array and binary deserialization

[gperinazzo]

Closes #243

[Alexander-L-G]

Tracked in https://jira.mongodb.org/browse/RUST-713

[patrickfreed]

Thank you @gperinazzo for submitting this patch, and also thank you @5225225 for identifying reproducible crash cases!

The fix looks good to me, but could we add the repros as test cases to ensure we don't accidentally introduce a regression in the future?

[gperinazzo]

Hey @patrickfreed, I added tests for #243 in the same format as the ones for #64. Let me know if you would like any more changes.

[patrickfreed]

Thanks! Could we actually drop the issue number from the test name and instead add a link to the Jira ticket (https://jira.mongodb.org/browse/RUST-713) in a docstring for the test instead? I think that way it'll be easier to follow for others seeing it for the first time (or for me in the future 🙂). I think that test name format was used from before MongoDB started officially maintaining this library.

[gperinazzo]

I've replaced the issue in the function name with a link to the Jira ticket as a docstring for the test and added the expect_err.

[patrickfreed]

Code changes LGTM! I authorized the CI run and in the meantime am tagging in the other members of the team as reviewers.

[isabelatkinson]

LGTM other than the lint error

[patrickfreed]

I went ahead and fixed the lint for you, if that's okay. Once the CI comes back green I'll merge it in, thanks again for your contribution!