How to write code for CVS

* Compiler options

If you are using GCC, you'll want to configure with -Wall, which can
detect many programming errors.  This is not the default because it
might cause spurious warnings, but at least on some machines, there
should be no spurious warnings.  For example:

	$ CFLAGS="-g -Wall" ./configure

Configure is not very good at remembering this setting; it will get
wiped out whenever you do a ./config.status --recheck, so you'll need
to use:

	$ CFLAGS="-g -Wall" ./config.status --recheck

* Indentation style

CVS mostly uses a consistent indentation style which looks like this:

void
foo (arg)
    char *arg;
{
    if (arg != NULL)
    {
	bar (arg);
	baz (arg);
    }
}

The file cvs-format.el contains settings for emacs and the NEWS file
contains a set of options for the indent program which I haven't tried
but which are correct as far as I know.  You will find some code which
does not conform to this indentation style; the plan is to reindent it
as those sections of the code are changed (one function at a time,
perhaps).

In a submitted patch it is acceptable to refrain from changing the
indentation of large blocks of code to minimize the size of the patch;
the person checking in such a patch should reindent it.

* Portability

If it is in ANSI C and it is in SunOS4 (using /bin/cc), generally it
is OK to use it without ifdefs (for example, assert() and void * as
long as you add more casts to and from void * than ANSI requires.  But
not function prototypes).  Such constructs are generally portable
enough, including to NT, OS/2, VMS, etc.

* Run-time behaviors

Use assert() to check "can't happen" conditions internal to CVS.  We
realize that there are functions in CVS which instead return NULL or
some such value (thus confusing the meaning of such a returned value),
but we want to fix that code.  Of course, bad input data, a corrupt
repository, bad options, etc., should always print a real error
message instead.

* Coding standards in general

Generally speaking the GNU coding standards are mostly used by CVS
(but see the exceptions mentioned above, such as indentation style,
and perhaps an exception or two we haven't mentioned).  This is the
file standards.text at the GNU FTP sites.

* Submitting patches

Please include a ChangeLog entry (see the GNU coding standards for
information on writing one) with patches.  Include a description of
what the patch does (sometimes the ChangeLog entry and/or comments in
the code are appropriate for this, but not always)--patches should not
be checked in unless there is some reason for them, and the
description may be helpful if there is a better way to solve the
problem.  In addition to the ChangeLog entry, there should be a change
to the NEWS file in the case of a new feature.

If you solve several unrelated problems, submit a separate
patch for each one.  Patches should be tested before submission.  Use
context diffs or unidiffs for patches.

Note that all submitted changes may be distributed under the terms of
the GNU Public License, so if you don't like this, don't submit them.
Submit changes to bug-cvs@prep.ai.mit.edu.

Generally speaking if you follow the guidelines in this file you can
expect a yes or no answer about whether your patch is accepted.  But
even in this case there is no guarantee because wading through a bunch
of submissions can be time consuming, and noone has volunteered to
offer any such guarantee.  If you don't receive an answer one way or
another within a month, feel free to ask what the status is.  You can,
if you wish, distribute your patch on mailing lists or newsgroups, if
you want to make it available before it gets merged.

* What is the schedule for the next release?

There isn't one.  That is, upcoming releases are not announced (or
even hinted at, really) until the feature freeze which is
approximately 2 weeks before the final release (at this time test
releases start appearing and are announced on info-cvs).  This is
intentional, to avoid a last minute rush to get new features in.
