QGIS Development

Welcome to the QGIS Development pages

Bugs, Features and Issues

If you find a bug, please report it!

You need an OSGeo account and login in order to submit bug reports. To get started, first create Create an OSGeo4 account.

Once you have your account, use QGIS issue tracking to search if the issue you’d like to report is probably already entered.

Issues

Issues are used to report bugs, request enhancements and submit patches. Redmine is more than a bug reporting system. Issues can be associated with a QGIS Milestone, allowing you to see progress towards completion. Completion of a Milestone not only requires closing bugs, but completing other tasks related to a release such as documentation, web site updates, packaging, and announcements.

Filing an Issue

Before reporting a bug

Before filing a bug, review the currently open issues to make sure that you aren’t creating a duplicate. If you have additional information on an issue, you can add it to the existing ticket. Third party plugins might also cause problems. If you have installed any, you should also verify that the problem is still reproducible without them. Please don’t report multiple unrelated bugs in a single bug report.

Plugin bugs

Plugin bugs must be opened in their respective bug tracking system. Check first if the plugin is listed in the plugin overview. If so, click on the plugin name then click “New issue”. Otherwise, consult the plugin documentation to find the address of the relevant bug tracking system or a developer to contact.

Steps

To report a bug choose New Issue from the menu bar. Note: You can also request an enhancement or submit a patch using the Ticket system.

Important information needed when opening a ticket:

  • Tracker - choose the ticket type from the drop-down list: Bug, Feature (new feature request) or Bounty (ticket for which a bounty has been defined)
  • Subject - a short description of the issue
  • Description - Provide a full description of the problem including steps to repeat it; if you think the bug could be related to a certain platform version or dependencies package version (GDAL, OGR, GEOS etc) include that as well. If your QGIS crashes if might be useful to include a backtrace (see below). A very important thing when reporting a bug is to boil down a minimum example that is needed to reproduce the bug. The chances of a bug being addressed in a timely manner is directly related to the speed with which the developer can reproduce the bug. If you make that hard for the developer, chances are the bug will be given up on or ignored for quite a while.
  • Priority - provide an estimate of the severity of the problem: Low (a problem which doesn’t affect QGIS usefulness), Normal (the default value, applicable to most bugs and nearly all feature requests), High (a bug which has a major effect on the usability of a package), or Blocker (a bug that makes QGIS totally unusable, causes serious data loss or a regression from a previous QGIS version)
  • Component - Choose the aspect of the application that is most closely associated with the problem
  • Milestone - If this issue affects a particular Milestone in the project choose it from the drop-down list
  • Version - Version of QGIS this issue affects
  • Platform - Choose the platform you are using

Before sending the bug, please check the formatting of your report by clicking on “Preview”. Please avoid editing existing reports, if not for typos. Better add further comments in any other case.

Creating a backtrace

If you have a crash it might be useful to include a backtrace as the bug might be not reproducible on an other machine.

On Linux QGIS automatically tries to use gdb to connect to the crashing process to produce a backtrace. But some distributions disable the possiblity to connect debuggers to a running processes. In that case gdb only produces a rather useless message like:

QGIS died on signal 11Could not attach to process.  If your uid matches the uid of the target
process, check the setting of /proc/sys/kernel/yama/ptrace_scope, or try
again as the root user.  For more details, see /etc/sysctl.d/10-ptrace.conf
ptrace: Operation not permitted.
No thread selected
No stack.
gdb returned 0
Aborted (core dumped)

In that case you should reenable that option by setting kernel.yama.ptrace_scope to 0 in /etc/sysctl.d/10-ptrace.conf (or /etc/sysctl.conf or some other file in /etc/sysctl.d/) and run sysctl -p as root. When you reproduce the crash after that, a backtrace will be printed instead.

If you cannot reproduce the crash, there should still be a core dump in the current directory, that can be analysed after the process has already terminated. It’s called core (on some systems a dot and the process id is append to the filename).

On some distributions the creation of core dumps is also disabled. In the event that you just get Aborted instead of Aborted (core dumped) when the crash occurs. Then you need to run ulimit -c unlimited before starting QGIS. You can also include that in your .profile, so that it’s always enabled when you login.

To produce a backtrace from the core file it you start gdb /path/to/the/qgis/binary core. The binary is usually /usr/bin/qgis or /usr/bin/qgis.bin on Debian with the GRASS plugin installed. In gdb you run bt which will produce the backtrace.

Log output on Windows

The nightly build in OSGeo4W (package qgis-dev) is built with debugging output, that you can view with DebugView. If the problem is not easy to reproduce the output might shed some light about where QGIS crashes.

Creating a patch

To be done

Road Map

Since QGIS 2.0 further development will occur based on a timebased roadmap.

Odd version numbers (2.1, 2.3 etc) are development versions.

Even version numbers (2.2, 2.4 etc) are release versions.

Release will happen every four month. In the first three month new development is taking place. Then a feature freeze is invoked and the final month is used for testing, bugfixing, translation and release preparations. When the release happens, a branch with a even release number is created and the master branch advances to the next odd version. After the release a call for packaging is issued.

Every third release (starting with 2.8) is a long-term-release (LTR) that is maintained until the next long-term-release occurs.

Development phase

In the development phase developers work on adding new features for the next release. Early adopters can use the nightly builds we have for all major platforms to see the development progress, do preliminary testing and provide bug reports and their thoughts to help with development.

Feature freeze

In the feature freeze phase new features are not allowed in anymore and the focus of everyone moves from enhancing QGIS to stablizing it. This also turns the nightly builds effectively into prereleases.

Users should start extensive testing of these prereleases in their environment to verify that there are no issues, they wouldn’t want to see in the upcoming release. All such issues should be reported (see Bugs, Features and Issues). Everything that goes unnoticed, will also end up in the next release. Only in case of serious problems a point release (eg 2.4.1) will occur. Therefore testing of the prereleases and reporting issues is very important.

In the feature freeze Developers monitor the hub and start working on fixing the reported issues.

With the begin of the feature freeze the translation files will be updated so that translators can start their work. Note that this might be an incremental process as although the features are frozen, bug fixes might still introduce translation string changes.

Release schedule

Following is the schedule for 2015

Week Date Event
(30 31.10 2.6 was released)
3 23.01 2.7 freeze begins
7 20.02 2.8 is released (LTR)
20 22.05 2.9 freeze begins
25 26.06 2.10 is released
38 26.09 2.11 freeze begins
42 23.01 2.12 is released

Location of prereleases / nightly builds

Platform Location
Windows Weekly release candidate (standalone installer)
OSGeo4W
Linux Debian
Ubuntu
MacOS Mac OS

Development

See INSTALL

API Documentation

There is API documentation for C++.

Plugin Development

QGIS has a plugin infrastructure. You can add a lot of new functionality by writing your own plugins.

These plugins can either be written in C++ or in Python

C++ plugin development

To learn how to write your first C++ plugin, please go here: Developing C++ plugins

Via a script you will generate a plugin stub which can be used further.

Python plugin development

QGIS has a lot to offer for python developers too.

QGIS has python bindings so you can automate tasks in QGIS via python.

Interested in python plugin development, go to Developing Python plugins or have a look into the PyQGIS-Developer-Cookbook.

Looking for examples of python plugins, see http://plugins.qgis.org

You can find the QGIS-iface which you can use via python here:

http://qgis.org/api/classQgisInterface.html (for QGIS testing)

http://qgis.org/api/2.0/classQgisInterface.html (for QGIS 2.0)

http://qgis.org/api/1.8/classQgisInterface.html (for QGIS 1.8)

Adding GRASS tools

adding-grass-tools