= Patch Guidelines == =
Any invasive or non-trivial patches should preferably adhere to the following recommendations:
* Search the [http://sourceforge.net/mailarchive/forum.php?
forum_id= 1919 flightgear-devel list archives] ([http://www.flightgear.org/mail.html old]) for any relevant discussion and then post to the flightgear-devel [[mailing list]] describing your idea and discussing the scope of effort required. * if you have developed several different features, make sure '''not''' to provide one big patch for all of these changes, but instead several smaller ones for each individual feature (likewise, use separate threads on the mailing list as well), that way you will enable developers to easily and independently review/discuss your patches [http://email@example.com/msg16986.html].
* Try to make your patch optionally minimally invasive:
** provide compile time switches to generally enable or disable your modifications (i.e. using #ifdefs, [http://sources.redhat.com/autobook/ autoconf and automake] macros) That way, you will ensure that your patch can
be easily disabled (excluded from compilation while remaining in the source tree) if it should cause trouble while any issues are addressed. This applies in particular if your patch introduces any extra dependencies (i.e. libraries) or is any way platform specific.** provide capabilities to enable or disable your code modifications at startup time or even at runtime, using command line options (check out $FG_SRC/Main/options.cxx) or preferably the PropertyTree/SGPropertyListeners and some simple GUI dialog (check out $FG_ROOT/gui) to enable developers and users to decide whether they want to activate your code. That way, it can be ensured that your code doesn't interfere with any other FlightGear components. This will make potential bug tracking much easier and the chances of your code remaining in the source tree are much better as well.
** if you intend to add new features that may benefit from proper documentation, make sure to also provide patches to the documentation files provided under $FG_SRC/mini-docs and $FG_ROOT/Docs
* Try to carefully document those passages in your source code that:
** are non-obvious or unfinished
* If you need to print output to the terminal, make sure to use the SG_LOG logging mechanism, using the appropriate log level. Use this command sparingly, as excessive logging information has negative impact on framerate, especially on some platforms (you can however easily use switches to generally enable/disable output of debugging information). When committing a patch, make sure you have either removed or commented out any cout or cerr statements that you have used during private debugging sessions.