Fix displaying escaped characters in message boxes

[sewe2000]

…val dialog

I changed the TextType in MessageBox class to plain text so as to display the & character correctly and prevent HTML injection.
Fixes #9356

Screenshots

Type of change

• ✅ Bug fix (non-breaking change that fixes an issue)
• ✅ Breaking change (causes existing functionality to change)

[droidmonkey]

This isn't the correct fix because you still want to HTML escape the title otherwise HTML elements in the title will be rendered like < and >. You should keep the HTML escaping but convert & back to just & using a simple QString::replace.

I actually think this is a bonefide Qt bug in that it is not rendering escaped HTML characters correctly.

[phoerious]

Qt is doing some on-the-fly content detection AFAIK, which is ridiculous. Setting it to a fixed value is definitely part of the solution.

[sewe2000]

OK, I made some fixes according to @droidmonkey's suggestions. Now it escapes HTML and displays & correctly.

[phoerious]

I think the solution is incorrect. You are partially reverting your HTML escaping, which makes no sense to me. Either you escape or you don't and if you do, it either displays correctly (i.e., the message box accepts HTML) or it doesn't (then you get double escaping).

Instead of trying to mess with the escaping, you should set the textFormat property of the message box to PlainText. https://doc.qt.io/qt-6/qmessagebox.html#textFormat-prop
I think the default is AutoText, which is why sometimes you get HTML and sometimes you don't.

Invalid

[droidmonkey]

Had to give this a one-two punch. HTML escaping the titling is necessary to keep the title intact, and the message box needs to be set explicitly as "Rich Text" so that html formatting in the message will be shown and escaped characters will be decoded properly. This is the same problem that the Entry Preview Panel had.