Add decoding option to allow decoding CBOR byte string into Go time.Time

[ssuriyan7]

Currently, when cbor.Unmarshal is called with a byte string data item and time.Time as destination type, it causes UnmarshalTypeError. This change adds a decoding option to specify if this operation can be allowed.

• Default value for this option (ByteStringToTimeForbidden) blocks decoding a byte string data item into a Go time.Time value.
• ByteStringToTimeAllowed allows decoding a byte string data item into a Go time.Time value.

Description

PR Was Proposed and Welcomed in Currently Open Issue

• This PR was proposed and welcomed by maintainer(s) in issue feature: Allow decoding a byte string into time.Time value #497
• Closes or Updates Issue feature: Allow decoding a byte string into time.Time value #497

Checklist (for code PR only, ignore for docs PR)

• Include unit tests that cover the new code
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[fxamacker]

@ssuriyan7 Thanks for opening this PR! I left a couple of suggestions.

[fxamacker]

We should escape control characters and non-printable characters in the error message.

Suggested change

	return time.Time{}, false, errors.New("cbor: cannot set " + string(b) + " for time.Time: " + err.Error())
	return time.Time{}, false, errors.New("cbor: cannot set " + strconv.Quote(string(b)) + " for time.Time: " + err.Error())

[fxamacker]

Maybe add a test with byte string containing some invalid UTF-8 characters.

[benluddy]

I opened #524 to nudge this over the finish line. This is necessary for cases that were dependent on the behavior of the bug #501, which has since been fixed. Thank you @ssuriyan7 for your work on this! I took care to retain you as the commit author on my updated branch.

[fxamacker]

This PR is completed by @benluddy's PR #524.

Thanks @ssuriyan7 for opening this PR and your other contributions too! 👍