Replace Option::unwrap() with Option::ok_or_else() with descriptive message

[kylecarow]

The only thing I would want your input on this the verbiage of the new error message:

File extension not specified

versus the possible times a None is returned by PathBuf::extension():

The extension is:
- None, if there is no file name;
- None, if there is no embedded .;
- None, if the file name begins with . and has no other .s within;
- Otherwise, the portion of the file name after the final .

edit: I think the updated error message is fine.

[kylecarow]

@calbaker its also possible for OsStr.to_str() to panic at the unwrap, because OsStr can hold non-utf8 data and str cannot

But I don't think it would be worth making a specific error message just for the case someone provides non-utf8 data in the file extension or something

[calbaker]

@kylecarow , I think you could change

ok_or_else(|| anyhow!("Unable to parse file extension: {:?}", file))?

to something like

ok_or(|e| anyhow!("{e}\nUnable to parse file extension: {:?}", e, file))?

to preserve whatever the native error message is as context.

[kylecarow]

Hm, I don't know that the native error message really exists. The unwrap was on an Option, not a Result, so the error was just about unwrapping on a None

[calbaker]

@kylecarow , I'd lean toward also getting rid of this unwrap with a separate message since it's not much additional effort.

[kylecarow]

@calbaker done, see latest commit