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= cvsps README =

== Overview ==

CVSps is a program for collecting patchsets from a CVS repository. The
original use case was that its reports were useful for human
inspection by developers working on projects using CVS, but nowadays
the --fast-export option (which emits the history as a git-style
fast-import stream) is more interesting.

This tool was written and maintained until 2.2b1 by David Manfield,
who reported his "thanks to my employer Cobite and Robert Lippman,
who've given me time to develop this tool".  The 3.x versions
with fast-export dumping are maintained by Eric S. Raymond.

== Change notices and deprecations ==

If you have not used an older version of CVSps, you can skip this section.

The 3.x versions have changed significantly.  In 2012, CVS use is
declining swiftly (GNU CVS hasn't been updated since 2004) and the
original use case for this tool - browsing change sets in a live CVS
repository - is obsolete.  The 3.x versions are more focused on the
--fast-export mode.

Accordingly, a large amount of old code and options have been
discarded in order to reduce CVSps's complexity and improve its
performance.  It now always runs in what used to be cvs-direct mode,
doing client transactions with the CVS server and not relying on local
CVS commands at all.  Consequently, all the hairiness around caching
and different log/rlog versions is gone and the tool is much faster.
Also, it is no longer required that CVSps be run in a CVS checkout
directory; it can run from a repository directory, or actually 
from anywhere at all providing CVSROOT is set or --root is used.

The old -A option enabling ancestry-branch tracking didn't work 
and has been dropped (equivalent topological analysis is done in
fast-export mode). The new -A option accepts an author-mapping file
in the same format traditionally accepted by git-cvsimport, cvs2git,
git-svn, reposurgeon, and other similar tools.

The old-style non-fast-export reporting mode is still supported, but
deprecated.  In the future, it is possible that it may be dropped
entirely.

== Compiling ==

Do 'make' and 'make install'.  This is very plain-vanilla ANSI C
and should run on any Unixoid OS.

== Dependencies ==

The -g diff-generation option of cvsps depends on diff and sed at runtime.

== Testing ==

'make check' runs a regression-test suite.

== Running ==

Note: not all options are necessarily discussed here.  Please check the
output of 'cvsps -h' and/or the manual page for the most up-to-date info.

a) General theory of operation

CVSps operates by parsing 'cvs rlog' output fetched from the CVS
server.  To run it, you must be in the working directory of a cvs
project.  CVSps handles subdirectories fine, so run it in the top
directory of your project.

The --fast-export switch produces a git-style fast-import stream on
standard output.  The rest of this section describes the older default
format intended for human inspection.

b) Old-style changeset reporting

CVSps's output is information about patchsets.  A patchset looks like:

---------------------
PatchSet 63 
Date: 2001/03/09 18:21:15
Author: sneakums
Branch: sneakums-nasty-hack
Tag: (none) 
Branches: 
Log:
First steps towards separating rfk from it nki source.  The primary
aim is to rough out the interface, specified in nki.h.  Expect the
implementation to suck.

Members: 
	src/Makefile.am:1.6->1.6.2.1 
	src/messages.h:1.9->1.9.2.1 
	src/nki.c:1.1->1.1.2.1 
	src/nki.h:1.1->1.1.2.1 
	src/robotfindskitten.c:1.15->1.15.2.1 

---------------------

This patchset report shows the date, the author, log message and each
file that was modified.  For each file the pre-commit and post-commit
revisions are given.  You can also see if the files are on a branch,
as well as the tag (see TAGS below).

Patchsets are ordered by commit timestamp, so as long as the clock on
your CVS server is monotonic, the numbering of patchsets should be
invariant. (see COMPATIBILITY below).

c) Limiting the patchset output.

The default output of CVSps is to show all patchsets.  This can be
filtered in one of many ways.  These flags can be combined to really
limit the output to what you're interested in.

By patch-set number.  With the -s <ps range> you can specify
individual PatchSets by number or by range.  Ranges can be of the form
'<number>', '<number>-', '-<number>' and of course
'<number>-<number>'.  Multiple ranges can be specified seperated by
commas.  E.g.

cvsps -s 999-1020,1025,4956-

By author.  With the -a <author> flag you limit the output to patchsets
committed by a given author.  The author is usually the UNIX login id.

By file.  With the -f <file regex> flag you limit the output to patchsets 
that have modified the given file.  Because a regular expression can have
many pieces 'or'ed together, you can specify many different files here,
for example (note also the use of the ^ character):

cvsps -f '^net/ipv4|^net/core'

By date.  With one date specification, CVSps shows only patchsets newer
than the date given, and with two dates, it shows patchsets between the
two dates.

*NOTE ON DATE FORMAT*.  The preferred date format is in RFC3339 style:
'yyyy-mm-dd-Thh:mm:ss'; 'yyyy/mm/dd hh:mm:ss' is also accepted.  In
both cases time is given as localtime and hh is in 24 hour format.
CVS tends to display times as GMT, but parse dates as localtime, so
when using the '-D' with cvs you need to convert from GMT to localtime
in your head.  CVSps is not as fancy.  It treats all dates as if in
localtime, and therefore you give CVSps dates the same way it gives
them to you.  But note that --fast-export exports git-style UTC times.

By branch.  With the -b <branch> flag you limit the output to patchsets
that have modified the history of the given branch.  Note, this 
doesn't necessarily mean the commit itself was made on the branch, since
the files in question may have existed prior to the branch point, in which
case changes made to a given file before the branch point affect the file
as it exists in the head of the branch.  If you want to restrict to the
main branch, use a branch of 'HEAD'.

By log comment.  With the -l <regex> flag you can limit the ouptut to
patchsets with the commit message matching the regex.

By tag.  With the -r <tag1> -r <tag2> you can limit the patchsets to
commits after a given tag1 and, optionally, before tag2.

d) viewing the changes made by a patchset.

To show the 'diff' output for a given patchset, use -g.

It will show you the diff of changes made by the selected commits.
Some effort was made to ensure that the patches are valid, even in the 
case of removing or creating files, a case in which 'cvs diff' fails.  
The patches generated are, generally speaking, applyable in the working
directory with the '-p1' option to the patch command.

e) what is timestamp fuzz factor (-z option)?

There's another annoying feature of CVS.  When you commit a large change,
the timestamp on the change is created per file committed.  For example:
if you commit changes to 60 files on a slow server, taking, say, 60
seconds, the 'commit time' as given in the log message for the first file
will differ from that of the last file by 60 seconds.

The fuzz factor attempts to workaround this by saying: commits by the same
author, using the same log message, within <fuzz> seconds are considered
part of the same patchset.  The default fuzz is 300 seconds (5 minutes).

== TAGS ==

Please read the manual page.

== COMPATIBILITY ==

One of the main goals of cvsps was to make the patchset numbering
stable across all time, as long as no funny-business is done to the
repository files themselves.

Unfortunately, as bugs have been fixed, the numbering has changed.  This is most
regrettable, but unavoidable.

Additionally, in version 2.0, two changes have been made which will
'renumber' the patch sets.

1) The false 'globbing' of two commits from nearly the exact same time, by the
same person, with the same log description but to different branches.  Now,
these will be reported as 2 patchsets instead of one.

2) The creation of a large volume of patchsets for 'file xyz was
originally added on branch' log messages.  This occurs whenever a file
is originally born on a branch, and is exacerbated by the fact that
even when all of these files are created with a single commit, the
'file xyz...' messages, which contains the actual file name, are
different, causing a proliferation of these unwanted patchsets.  These
patchsets are now silently eliminated from the output.

== Known Problems (this will become the FAQ if anyone ever A any Q). ==

1) What is the '*** file xyz doesn't match strip_path abc' error?

This error occurs when one of the subdirectories of the directory you
ran CVSps in is checked out from a different repository.  CVSps tries
to remove the repository path information from the filenames that it
gets to give you working-directory local pathnames.  It does this 
at startup by parsing the CVS/Root and CVS/Repository files.  If 
the contents of these two files is different for some subdirectory,
all of the files in that subdirectory will be ignored. 

You can always run CVSps in that subdirectory, and since it IS a 
separate repository, that does make a little bit of sense.

//end