Bug 56061 – selectionStart reports wrong caret position when the last characters are newlines

• Component: Forms
• Status: RESOLVED FIXED

[Ryosuke Niwa]

http://crbug.com/56971

What steps will reproduce the problem?
1. Put some newlines in an empty textarea.
2. Read its selectionStart property via Javascript.

What is the expected result?
It should return the a number equal to the number of newlines.

What happens instead?
It always returns 1.

It may be a bug in Webkit, since Safari fails too. I did a reduction that shows the problem very easily:
http://martinml.com/textarea.html

This is especially annoying in a phpBB forum editor, since if you want to put some newlines and then click the button to insert a bbcode tag, it's inserted just after the last text, and not after the newlines.

[Ryosuke Niwa]

Created attachment 85260 [details]
demo

This is a failed attempt to write a layout out for this bug.  It seems like the bug can be reproduced only if we ran it manually.

[Ryosuke Niwa]

Created attachment 85262 [details]
fixes the bug

[Kent Tamura]

Comment on attachment 85262 [details]
fixes the bug

View in context: https://bugs.webkit.org/attachment.cgi?id=85262&action=review

> Source/WebCore/editing/SelectionController.cpp:171
> +        // See https://bugs.webkit.org/show_bug.cgi?id=56061

nit: I feel the bug entry doesn't have additional information and ChangeLog is enough.

[Ryosuke Niwa]

(In reply to comment #3)
> (From update of attachment 85262 [details])
> View in context: https://bugs.webkit.org/attachment.cgi?id=85262&action=review
> 
> > Source/WebCore/editing/SelectionController.cpp:171
> > +        // See https://bugs.webkit.org/show_bug.cgi?id=56061
> 
> nit: I feel the bug entry doesn't have additional information and ChangeLog is enough.

Ok. Do you think I can also get rid of the line above where I say "// Even if selection was not changed, selection offset may have been changed." ?

[Kent Tamura]

(In reply to comment #4)
> Do you think I can also get rid of the line above where I say "// Even if selection was not changed, selection offset may have been changed." ?

No.  This line looks helpful.

[Ryosuke Niwa]

(In reply to comment #5)
> (In reply to comment #4)
> > Do you think I can also get rid of the line above where I say "// Even if selection was not changed, selection offset may have been changed." ?
> 
> No.  This line looks helpful.

Ok.  Thanks for the review.  Landing it now.

[Ryosuke Niwa]

Committed r80679: <http://trac.webkit.org/changeset/80679>