D.5. Hacking Bugzilla

D.5.1. Things that have caused problems and should be avoided

1. Usage of variables in Regular Expressions

   It is very important that you don't use a variable in a regular expression unless that variable is supposed to contain an expression. This especially applies when using grep. You should use:

   grep ($_ eq $value, @array);

   -- NOT THIS --

   grep (/$value/, @array);

   If you need to use a non-expression variable inside of an expression, be sure to quote it properly (using \Q..\E).

D.5.2. Coding Style for Bugzilla

While it's true that not all of the code currently in Bugzilla adheres to this (or any) styleguide, it is something that is being worked toward. Therefore, we ask that all new code (submitted patches and new files) follow this guide as closely as possible (if you're only changing 1 or 2 lines, you don't have to reformat the entire file :).

The Bugzilla development team has decided to adopt the perl style guide as published by Larry Wall. This giude can be found in "Programming Perl" (the camel book) or by typing man perlstyle at your favorite shell prompt.

What appears below if a brief summary, please refer to the perl style guide if you don't see your question covered here. It is much better to submit a patch which fails these criteria than no patch at all, but please try to meet these minimum standards when submitting code to Bugzilla.

• Whitespace

  Bugzilla's preferred indentation is 4 spaces (no tabs, please).

• Curly braces.

  The opening brace of a block should be on the same line as the statement that is causing the block and the closing brace should be at the same indentation level as that statement, for example:

  if ($var) { print "The variable is true"; } else { print "Try again"; }

  -- NOT THIS --

  if ($var) { print "The variable is true"; } else { print "Try again"; }

• Cookies

  Bugzilla uses cookies to ease the user experience, but no new patches should require user-side cookies.

• File Names

  File names for bugzilla code and support documention should be legal across multiple platforms. \ / : * ? " < > and | are all illegal characters for filenames on various platforms. Also, file names should not have spaces in them as they can cause confusion in CVS and other mozilla.org utilities.

• Javascript dependencies

  While Bugzilla uses Javascript to make the user experience easier, no patch to Bugzilla should require Javascript.

• Patch Format

  All patches submitted for inclusion into Bugzilla should be in the form of a "unified diff". This comes from using "diff -u" instead of simply "diff" when creating your patch. This will result in quicker acceptance of the patch.

• Schema Changes

  If you make schema changes, you should modify sanitycheck.cgi to support the new schema. All referential columns should be checked.

• Taint Mode

  All new cgis must run in Taint mode (Perl taint and DBI taint), and existing cgi's which run in taint mode must not have taint mode turned off.

• Templatization

  Patches to Bugzilla need to support templates so they do not force user interface choices on Bugzilla administrators.

• Variable Names

  If a variable is scoped globally ($::variable) its name should be descriptive of what it contains. Local variables can be named a bit looser, provided the context makes their content obvious. For example, $ret could be used as a staging variable for a routine's return value as the line return $ret; will make it blatantly obvious what the variable holds and most likely be shown on the same screen as my $ret = "";.

• Cross Database Compatability

  Bugzilla was originally written to work with MySQL and therefore took advantage of some of its features that aren't contained in other RDBMS software. These should be avoided in all new code. Examples of these features are enums and encrypt().

• Cross Platform Compatability

  While Bugzilla was written to be used on Unix based systems (and Unix/Linux is still the only officially supported platform) there are many who desire/need to run Bugzilla on Microsoft Windows boxes. Whenever possible, we should strive not to make the lives of these people any more complicated and avoid doing things that break Bugzilla's ability to run on multiple operating systems.