How to display hidden characters by default (ZERO WIDTH SPACE ie. &#8203)

207
votes

I just lost part of my weekend because of this ... joker - zero width space. I just used some snippets from google groups and didn't recognize that there are doubled characters, because Idea (11) didn't show them, which was causing problems with parsing config file of my app... I discovered it accidentally in vi.

Is there any way to display such things in IntelliJ (or some other way to examine files) without using external editors.

IntelliJ 11 / Mac OS 10.7

edit - sample

These two lines looks identical, in browser and also in Idea. You can see in page's code that in first - commented line there is hidden zero width space between mysql:// and localhost, which causes problems. Of course if you expect that 'joker', you can try to use search and replace it, however nobody expects the sign that should not be there, especially if he cannot see it in any way. 

#db.default.url="jdbc:mysql://​localhost/play-fullcalendar"
 db.default.url="jdbc:mysql://localhost/play-fullcalendar"
2
intellij-ideaphpstormwhitespace
This character should be banned by an international treaty. It's a weapon of massive distraction. I lost a whole day trying to find out what's the cause of a mysterious error showing up in my js console. Seriously, a zero-width character? That's a perfect recipe for trouble. What was the UTF standards committee thinking? – Nick
@Nick your comment inspired me to find why UTF included this joker thing. Check this out for the beauty of ZeroWidthCharacter: ptiglobal.com/2018/04/26/… – Genius

2 Answers

383
votes

Not sure what you meant, but you can permanently turn showing whitespaces on and off in Settings -> Editor -> General -> Appearance -> Show whitespaces.

Also, you can set it for a current file only in View -> Active Editor -> Show WhiteSpaces.

Edit:

Had some free time since it looks like a popular issue, I had written a plugin to inspect the code for such abnormalities. It is called Zero Width Characters locator and you're welcome to give it a try.

88
votes

A very simple solution is to search your file(s) for non-ascii characters using a regular expression. This will nicely highlight all the spots where they are found with a border.

Search for [^\x00-\x7F] and check the box for Regex.

The result will look like this (in dark mode):

zero width space made visible