Blockquote glitch in editor in Chrome 6 and 7

Question

Please star this ticket rchern helpfully created to help have the bug addressed:

Issue 56095: Markdown behavior since v6 branch

Well, I would just bump up this question with an edit, but my meta rep isn't high enough. So I'm posting this as a new question.

Here's the problem: in the latest stable version of Google Chrome (6.0.472.53) -- now out of beta -- clicking on the "Blockquote" button in the editor results in a strange textual anomaly.

Below are a couple of screenshots illustrating this issue.

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Before clicking the Blockquote button

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After clicking Blockquote button

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Steps to reproduce:

1. Using the latest stable version of Chrome, navigate to StackOverflow.
2. Open up any page with an editor in it -- either to answer a question or to ask a new question.
3. Type and select some text in the editor.
4. Click on the Blockquote button.

The above strange effect above always happens, as far as I can tell.

The main reason I am posting this is that the accepted answer to the previous question I linked to was "Beta browsers are not supported"; and Chrome 6 is now out of beta.

Answer 1

EDIT

Secretly I added the workaround for chrome 6 only, I upgraded to chrome 7 today and the bug is back. I really don't want to make this workaround part of WMD.

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Ok, this happens cause of a pretty serious bug in the Chrome 6 regular expression engine.

Under certain circumstances it fails to set back references properly. So we have this code:

this.selection = this.selection.replace(/(^\n*)/, "");
// In Chrome 6 RegExp.$1 is set to the previous match eg: ("whatever") instead of being empty   
this.startTag = this.startTag + RegExp.$1;

My workaround is to add:

if (navigator.userAgent.match(/Chrome\/6/)) {
    "X".match(/()./);
}

this.selection = this.selection.replace(/(^\n*)/, "");

Of course this is totally horrid, and should be fixed in the web browser.

In fact it is so bad I do not want to include this in wmd.js

This bug also happens to be a heisenbug, when debugging it if your first breakpoint is too early, stepping through shows that everything is good.

Answer 2

Chrome 5: works OK
Firefox 3.6.x: works OK
IE8: works OK
Opera 10: works OK
Safari 5: works OK

Unfortunately, this is a bug in Chrome 6 (final), and should be reported to Google.

Don't get me wrong, I love Chrome -- it is my browser of choice and I am just as excited as anyone else to have a sweet new version -- but this really is not our bug.

Answer 3

The problem seems to be happening in the wrap() call in doBlockquote.

Oddly, if I comment it out, the problem goes away and blockquote seems to works correctly in Chrome 6. I'm working with the obfuscated version of WMD and I haven't got the patience to chase down what is really happening here.

if(/^(?![ ]{0,3}>)/m.test(_a.selection)){
  // comment out the following line and all is good in Chrome 6
  _8.wrap(_a,_2.wmd_env.lineLength-2);

  _a.selection=_a.selection.replace(/^/gm,"> ");
  _13(true);
  _a.skipLines();
}else{

Answer 4

This indeed is a bug to be fixed by the Chrome.

it can be fixed as below:

Expected output:

Blockquote

What happens instead:

Blockquote

Blockquote> BlockquoteBlockquote

Blockquote

The fix:

1. Search the file for "wmd.Chunks.prototype.addBlankLines = function"

2. Within this function locate where two variables are assigned:

"var regexText; var replacementText;"

3. Just after these variables add the following IF statement:

   if (navigator.userAgent.match(/Chrome/)) {
       "X".match(/()./)
   }
   

4. This fixes the chrome issue with block quotes and is the fix currently implemented by StackOverflow.com.