Bugmasters/Projects/CoreLayout

Core:Layout Triage Team

This is a good triage task for front-end developers. Help us go through UNCONFIRMED Core:Layout bugs, talk with the bug reporters, replicate the bugs, and attached reduced test cases.

The hardest part about layout bug triage is being able to tell apart "is a valid bug" and "is not a valid bug". This typically involves understanding the spec well enough to understand what behavior it requires. It also typically involves reducing the testcase enough that it's possible to try to figure out what parts of the spec are relevant. The really rare skill here is this ability to reduce testcases well. Here are some useful slides that explain how to create reduced testcases.

• UNCONFIRMED Core::Layout bugs
• Sort the list different ways and look over it.
• Pick a bug and read through it and its comments to thoroughly understand it.
• Is the bug reproducible?
• It may be UNCONFIRMED because it is not clear whether a reproducible issue is a problem within a Mozilla product or whether the problem lies somewhere else.
• Search for bugs already tagged testcase-wanted and try to develop a testcase.

Creating a simplified DOM/layout test

• These tips are from a talk by Martijn Wagners
• This saves time for the developer
• It is easier to convert into automated tests

Tools

• DOM Inspector
• Error Console
• Disabling javascript
• HTTP Headers (for network related problems)

Define the problem - URL/example? - Steps to reproduce? - Extensions installed? - Screenshot?

Layout bugs

• Example 1: pop up menus on page are not displayed properly
• https://bugzilla.mozilla.org/show_bug.cgi?id=442304
• example 2: Hovering over links in large list is slow
  • https://bugzilla.mozilla.org/show_bug.cgi?id=449046
• Performance regression
• Adding a way to measure the perf regression

DOM bugs

• example 1: text entry field unable to take focus
  • https://bugzilla.mozilla.org/show_bug.cgi?id=440614
  • Typical editor problem
• example 2
  • https://bugzilla.mozilla.org/show_bug.cgi?id=387406
  • Form -> Select -> Jump-Menus, selectedIndex can be set to a disabled option
  • SelectedIndex and disabled options in select elements

Problems - Report too vague, no url that shows the problem - Difficult/impossible to reproduce - Problem somewhere in an ajax library (which are usually huge) - Problems that can only be seen on a network (http headers,e tc)

Example problem bug

• https://bugzilla.mozilla.org/show_bug.cgi?id=444322

Firefox 3 onLoad event fireing before the page is fully loaded.

• Page that shows the problem, but:
  • It's not happening very often
  • It seems to happen only over a (slow?) network connection
  • The JS code behind it is complicated

More info - http://developer.mozilla.org/en/Reducing_testcases - https://wiki.mozilla.org/MozillaQualityAssurance:Triage