Fix Message::bodySummary when preg_match fails

[XilefNori]

preg_replace returns "false" on failure which interpreted as OK result which is wrong.
Reform statement in positive manner makes it right

[GrahamCampbell]

I think the right fix here is just to add a === 0?

[XilefNori]

I think the right fix here is just to add a === 0?

I guess you right

[jtojnar]

❌ If we did as you suggest, the function might return non-printable bytes when preg_match is “broken”. Note that the documentation specifically says “Will return null if the response is not printable.” and we just cannot tell without preg_match.

By the way, how does preg_match even break?

[XilefNori]

By the way, how does preg_match even break?

For example when you has utf-8 malformed symbol in tested string (which you get when cut utf-8 string code in the middle of multibyte UTF character).

❌ If we did as you suggest, the function might return ç when preg_match is “broken”. Note that the documentation specifically says “Will return null if the response is not printable.” and we just cannot tell without preg_match.

No, it will not. When preg_match breaks you get false (!== 0), therefore it will return null.

if (preg_match('/[^\pL\pM\pN\pP\pS\pZ\n\r\t]/u', $summary) === 0) {
    return $summary;
}

return null;

[jtojnar]

No, it will not. When preg_match breaks you get false (!== 0), therefore it will return null.

Right, but that is precisely what I would expect based on “Will return null if the response is not printable.” UTF-8 malformed symbol is not printable.

[jtojnar]

Turns out I was misunderstanding you. It was previously returning a malformed UTF-8 and your change makes it return null. I added a test: #559