make_clickable() breaks when colon in hash

[Viper007Bond]

make_clickable() doesn't like this string:

<a href="http://en.wikipedia.org/wiki/URI_scheme#tel:">http://en.wikipedia.org/wiki/URI_scheme#tel:</a>

It results in this HTML:

<a href="http://en.wikipedia.org/wiki/URI_scheme#tel:"><a href="http://en.wikipedia.org/wiki/URI_scheme#tel" rel="nofollow">http://en.wikipedia.org/wiki/URI_scheme#tel</a>:</a>

Specifically it's the colon that is causing the issue. It can be a part of the URL too, it doesn't have to be a part of an anchor.

[nacin]

Well, colons are a reserved character and invalid in URLs: ​http://www.blooberry.com/indexdot/html/topics/urlencoding.htm. But they're not uncommon in hashes. Trac uses them, for comments (#comment:0). I'd be inclined to allow colons when used in a hash. But not sure this is a defect.

[Viper007Bond]

Ah, okay. I fixed the ticket title then.

Really it should ignore anything inside of an existing <a> tag (note it's making a hyperlink's text clickable) but I'm not sure how feasible that is while maintaining good regex performance.

[SergeyBiryukov]

Related: #21974

[alex-ye]

in related to make_clickable() , could you see this ticket, please ?
​http://core.trac.wordpress.org/ticket/23756

[ericmann]

Add some tests for a couple of specific hash conditions.

[ericmann]

Added a test method to check three potential URL structures:

1. Url with trailing colon (used in ticket description)
2. Url with embedded colon in hash (used in Trac URLs specifically)
3. Url with trailing period

Finding parity between the first and third cases is the difficulty here. The original make_clickable() method specifically only allows punctuation characters when followed by non-punctuation characters (meaning case #2 will actually work). Removing the colon from this punctuation check will allow case #1 to pass, but then case #2 will fail.

Whatever fix is introduced, retaining the functionality of case #3 (trailing non-colon punctuation) is vital to allowing links that are made clickable to be placed at the end of a sentence, before a coma, etc.