Bug 10148 – REGRESSION: Semi-reproducible hang when editing textarea

• Component: HTML Editing
• Status: RESOLVED FIXED

[David Kilzer (:ddkilzer)]

I managed to create a hang in a locally-built debug build of WebKit r15648 while editing a textarea, again related to replying to Bug 8278 Comment #5.  I was smart enough to capture a Shark trace of the activity, which only shows four methods (if I remember correctly) being called repeatedly.

What I remember when hitting this hang:

1. Just did the steps in Bug 10143 to reproduce it.
2. Moved the cursor up to the first of three blank lines created between the two quoted paragraphs.  (Don't know if I used the arrow keys or the mouse to do this.)
3. Tried to insert more text by hitting Enter (or maybe another printable character?), then the hang started.

Will attach the Shark profile next.

[David Kilzer (:ddkilzer)]

Created attachment 9748 [details]
Shark profile of the hang

[David Kilzer (:ddkilzer)]

(In reply to comment #0)
> What I remember when hitting this hang:
> 
> 1. Just did the steps in Bug 10143 to reproduce it.
> 2. Moved the cursor up to the first of three blank lines created between the
> two quoted paragraphs.  (Don't know if I used the arrow keys or the mouse to
> do this.)

Between these two steps, I may have also tried to delete the extra characters after the SECOND quoted paragraph (but didn't run into Bug 10144 when doing it).

> 3. Tried to insert more text by hitting Enter (or maybe another printable
> character?), then the hang started.

[David Kilzer (:ddkilzer)]

Actually, that should be between steps 1 and 2, not between steps 2 and 3.

(In reply to comment #2)
> > 1. Just did the steps in Bug 10143 to reproduce it.
> 
> Between these two steps, I may have also tried to delete the extra characters
> after the SECOND quoted paragraph (but didn't run into Bug 10144 when doing
> it).
> 
> > 2. Moved the cursor up to the first of three blank lines created between the
> > two quoted paragraphs.  (Don't know if I used the arrow keys or the mouse to
> > do this.)
> > 3. Tried to insert more text by hitting Enter (or maybe another printable
> > character?), then the hang started.

[David Kilzer (:ddkilzer)]

This bug is semi-reproducible, although after following the steps below this particular behavior probably only happens 1 in 10 times.  It relies on the behavior from Bug 10143, which may be suspect in the first place.  This bug may become unreproducible if Bug 10143 is fixed.

Steps to reproduce:

1. Follow steps from Bug 10143 Comment #0:
    a. Open Bug 8278.
    b. Click "[reply]" link on Bug 8278 Comment #5.
    c. Put cursor on "blank" line between two paragraphs.
    d. Hit Delete key twice.
2. Use the mouse to place the cursor to the left of the greater-than character (">") on last line with a greater-than character (">").
3. Holding the Shift key down, arrow down twice.  This should highlight the entire last two lines in the textarea.
4. Hit the Delete key.
5. Use the mouse to place the cursor on the first of two blank lines (the top blank line) between the quoted paragraphs.
6. Hit Enter.

Expected results:

A blank line is added between the two quoted paragraphs.

Actual results:

One of the following:

- A blank line is inserted with no crash or hang (expected resutls!).
- A hang occurs (this bug).
- A crash occurs (Bug 10141 or a different crash).

Note that if the expect results occur, do the following:

A. Select all text in the textarea.
B. Hit Delete.
C. Start from Step 1b above.
Regression:

This does not occur on production Safari 2.0.4 (419.3) on Mac OS X 10.4.7 (8J135/PowerPC).

[David Kilzer (:ddkilzer)]

With Bug 10143 fixed, I don't see any "strange" behavior when following the steps in Comment #4, so I'm closing this as RESOLVED/FIXED.