Difference between revisions of "How To Help Developing Lazarus"

From Lazarus wiki
Jump to navigationJump to search
Line 62: Line 62:
  
 
To check to which data each revision correspondes one can use the [http://svn.freepascal.org/cgi-bin/viewvc.cgi/?root=lazarus Lazarus ViewCVS]. After the interval of revisions was reduced to a relative small number, like 25 or so, it may be quicker to check the revisions with ViewCVS and check which are possible canditates for the break, to speed up the final part.
 
To check to which data each revision correspondes one can use the [http://svn.freepascal.org/cgi-bin/viewvc.cgi/?root=lazarus Lazarus ViewCVS]. After the interval of revisions was reduced to a relative small number, like 25 or so, it may be quicker to check the revisions with ViewCVS and check which are possible canditates for the break, to speed up the final part.
 +
 +
One can obtein a particular revision using the command:
 +
svn update -r <revision number>
  
 
== Need more help? ==
 
== Need more help? ==

Revision as of 17:39, 6 January 2008

Deutsch (de) English (en) español (es) Bahasa Indonesia (id) 日本語 (ja) português (pt) русский (ru)

Prerequisites to developing Lazarus

There are two things to note:

  • You should have the latest release of FreePascal compiler (FPC) or a recent SVN version (i.e. a later version) of it. For obtaining FPC, see FreePascal download.
  • You must have the very latest Lazarus from SVN. For obtaining it, see Getting Lazarus via SVN.

Development areas

So now you have the latest version of Lazarus and wish to start improving it, but are asking yourself "where do I begin?" Well, that depends.

Known bugs

If you don't have any particular woes about Lazarus but just want to help, then I would recommend looking at the bug list Bug Tracker find a bug that you think you can fix, and start hacking. The Lazarus team has prioritized the open bugs in the Road To 1.0.

Documentation

Lazarus needs more documentation! If you don't want to fix a bug you can help by writing documentation. Even this page is a work in progress. If you have useful information to add, or if you see mistakes, please feel free to improve the contents of this page.

Look at Lazarus Documentation Editor and LCL Documentation Roadmap for some help on how to and a list of units to be documented.

The on-line IDE help is gradually being created as a part of the wiki. Recently a lot of stub pages of the Lazarus IDE documentation about the IDE windows have been added. When working in IDE, if you need help, press F1. You will be presented a help wiki page (possibly empty or incomplete). Improve it, if you have the relevant knowledge.

IDE

See these links: Extending the IDE, Road To 1.0.

Widgetsets ("interfaces")

A widgetset (WS) is the "glue code" between the LCL code parts that are independent of the target operating system and the target operating system itself. For each supported target OS, the corresponding WS units are to be found in one of the subdirectories under the C:\Lazarus\lcl\interfaces\.

Here is an outline of the steps one should follow, in order to improve a widgetset (description provided by Mattias Gärtner on the Lazarus mailing list on 2006-07-15). When making changes to a WS, it is not necessary to rebuild everything (Lazarus including the IDE), in order to test the efects of the changes. Proceed as follows:

* Create your testbed project (a small program
  which should contain the testing code for your WS changes);
* Setup the keyboard shortcuts for 'Build Lazarus' and 'Configure Build Lazarus' 
  (in IDE, go to Editor Options/Keymapping);
repeat
 * Configure "Build Lazarus" to only build the LCL 
  (in IDE, go to Tools/Configure "Build Lazarus");
 repeat
  * Make your improvement in the WS code;
  * Build Lazarus (in IDE, go to Tools/Build Lazarus 
    - this only rebuilds the LCL, which rebuilds also the selected WS);
  * Now compile your testbed project;
  * Run and debug your program;
 until no errors are found in your change;
 * Reconfigure "Build Lazarus" to build all 
   (in IDE, go again to Tools/Configure "Build Lazarus");
 * Build Lazarus and test the IDE;
until no errors/degradation due to your changes are found in IDE;
* Create a patch and send it (see further below for details).

How to submit your changes?

You will need to make a "patch" (see Creating A Patch). The preferred way of submitting the patch to the Lazarus developers is to create an issue in the bug tracker and attach the patch to it. Alternatively you can send it to the mailing list (maximum size 40kB) or the mailbox for patches patch@lazarus.dommelstein.net.

Dealing with regressions

From time to time changes on the Lazarus source code might cause features which worked before stop working. In case there is no clue of what caused the break it may be useful to do a iteration method to determine exactly which revision caused the problem.

This process is simple, althougth somewhat time consuming:

Suppose it works with rev 1000 and not with 5000. Then test with 3000. Testing requires updating the svn code, rebuilding lcl for desired widgetset, rebuilding a test application which uses the feature and testing this application. If it works, repeat with 3000 and 5000 as extremes. If not, use 1000 and 3000 as extremes.

After some time you should be able to isolate which revision broke it. This information makes fixing the problem much easier, so we encourage people helping to develop Lazarus to try this process and post this information on bug reports in case they are regressions with no clear clue of what went wrong.

To check to which data each revision correspondes one can use the Lazarus ViewCVS. After the interval of revisions was reduced to a relative small number, like 25 or so, it may be quicker to check the revisions with ViewCVS and check which are possible canditates for the break, to speed up the final part.

One can obtein a particular revision using the command:

svn update -r <revision number>

Need more help?

If you have any question you can ask them on one of the following places:

  • The Lazarus Mailing list (see Mailing list)
  • The #lazarus-ide IRC channel on irc.freenode.net.