crash: Fix crash in getUserFromMention as unformattedMessage gives undefined.

[Gautam-Arora24]

What was the error?
The unformattedMessage in getUserFromMention was giving undefined which was the cause of the crash.

How I solved this issue?
Since on mentioning the group in the ComposeBox was providing the same error. I used a constant called splittedMessage which splits the string through "*". This computation can provide me an array of length either 3 or 5. Thus, according to the size, I specified which index's value is further needed in the code. Hence, the bug was solved.

Before

After changes
No error

Fixes: #4460

[chrisbobbe]

Hi, @Gautam-Arora24! I've commented on the issue (here) with a potentially cleaner way of handling this.

In particular, I get the feeling that future readers of the code might prefer not to have to read and understand exactly what it means if completion.split('**') has a length of 3 or not. And if that did turn out to be necessary, I'd like to have a very clear code comment (with //), so a future reader doing some debugging could understand the code just as clearly as you do. 🙂

[chrisbobbe]

Thanks, @Gautam-Arora24!

In the summary line, let's use MentionWarnings: for the prefix, instead of crash:. We tend to use the prefix to help specify "what part of the code is affected". And the rest of the summary line makes it clear that a crash is being fixed, as well as narrowing it down to a particular function that can be found in the MentionWarnings component/file. 🙂

In the commit-message body, let's say "Use a conditional" instead of "Used a conditional". The mobile-app project differs from the main project in explicitly preferring the first form in the commit message body, not just the summary line, to explain the "what" of the commit message (i.e., what work is being done). We should get around to documenting this, but I usually refer to Greg's comment at #4079 (comment) to explain our reasoning. 🙂

I notice that the line lengths are well within bounds; thanks! 🙂 I do notice that the lines of the body are a bit uneven, though; the second is quite a lot shorter than the third. Do you mean the third line to begin a new paragraph? I tend to separate paragraphs with an extra line break, e.g.,

Use a conditional to check whether the unformattedMessage
is undefined or not.

Now, there is no error related to unformattedMessage as
undefined.

[Gautam-Arora24]

@chrisbobbe I hope that the commit is fine now.

[chrisbobbe]

Merged, thanks!