Commit 8b935dd5 authored by simonm's avatar simonm

[project @ 1998-04-07 11:22:41 by simonm]

remove old CVS Cheat Sheet.  New one is in docs/cvs-cheat-sheet.html.
parent 6857440d
CVS Cheat Sheet for fptools hackers.
------------------------------------
At Glasgow, we use CVS (Concurrent Version System) to keep track of
our sources for various software projects. CVS lets several people
work on the same software at the same time, allowing changes to be
checked in incrementally.
The full documentation for CVS is online, in info format (use 'info
cvs' or run emacs and type C-h i). A good source of tips is the CVS
FAQ, in /local/doc/gnu/CVS.FAQ. Bradley C. Kuszmaul provides a "to
the point" introduction to CVS at
http://arch.cs.yale.edu:8080/~bradley/cvs-instructions
This note is supposed to be a set of guidelines for how to use CVS at
Glasgow, and will probably evolve in time. The main thing to remember
is that most mistakes can be undone, but if there's anything you're
not sure about feel free to bug the local CVS meister (namely Me
<simonm@dcs.gla.ac.uk>).
The following guidelines should mean we don't step on each other's
toes too much. Ok, here's what you do:
Using Remote CVS
----------------
* (only if using CVS remotely, i.e. not at Glasgow):
To use remote CVS, you need to supply me with a username and
encrypted password. Once you've done that and the account has been
set up, you need to do:
cvs -d <username>@solander.dcs.gla.ac.uk:/local/fp/src/cvsroot login
CVS will ask for a password. You only need to enter the password once,
it will be recorded in .cvspass in your home directory.
setenv CVSROOT :pserver:<username>@solander.dcs.gla.ac.uk:/local/fp/src/cvsroot
The CVSROOT environment variable will be recorded in the checked-out
tree, so you don't need to set this every time either. Ignore the
instructions for setting CVSROOT below.
Using CVS for the First Time
----------------------------
* (ok, everybody now...) Firstly, identify which areas of the source
tree you'll be working on. The directory structure looks like this:
fptools/ghc GHC
fptools/happy Happy
fptools/haggis Haggis
fptools/green-card Green Card
fptools/nofib Nofib test suite
fptools/hdirect IDL-to-Haskell compiler
fptools/common-rts GHC/Hugs combined run-time system
For each directory, there's a mailing list: fp-cvs-ghc,
fp-cvs-nofib etc. Everyone on the mailing list is sent a message
automatically by CVS whenever someone checks in a change, this helps
to keep track of what's going on when several people are working on
related stuff. Ask the CVS meister to put you on the relevant
mailing lists.
* Create a .cvsrc file. Mine looks like this:
checkout -P
release -d
update -P
diff -c
It just gives default flags for some of the CVS commands. For instance,
the -P flag to 'checkout' says prune empty directories, which is
normally what you want.
Checking Out a Source Tree
--------------------------
* Check out your sources. The Approved Way (at least by me) to do
this is as follows:
$ CVSROOT=/local/fp/src/cvsroot
$ export CVSROOT
or, if you're using csh or tcsh:
$ setenv CVSROOT=/local/fp/src/cvsroot
$ cvs checkout fpconfig
At this point you have a new directory called 'fptools' which contains
the basic stuff for the fptools suite - including the configuration
files and literate programming tools.
$ mv fptools <directory>
You can call the fptools directory whatever you like, CVS won't mind.
$ cd <directory>
$ cvs checkout ghc happy
The second command here checks out the relevant modules you want to
work on. For a GHC build, for instance, you need at least the ghc
module (in fact you can get away with just that).
Committing Your Changes
-----------------------
* Build the software, if necessary. Unless you're just working on
documentation, you'll probably want to build the software in order
to test any changes you make. For GHC, instructions can be found
in the GHC installation guide, online in info format.
* Make changes. Preferably small ones first.
* Test them. You can see exactly what changes you've made by using
the 'cvs diff' command. For example,
$ cvs diff
lists all the changes (using the 'diff' command) in and below the
current directory. In emacs, C-c C-v C-= runs 'cvs diff' on the current
buffer and shows you the results.
* Before checking in a change, you need to update your source tree:
$ cd fptools
$ cvs update
This pulls in any changes that other people have made, and merges them
with yours. If there are any conflicts, CVS will tell you, and you'll
have to resolve them before you can check your changes in. The
documentation describes what to do in the event of a conflict.
It's not always necessary to do a full cvs update before checking in
a change, since CVS will always tell you if you try to check in a file
that someone else has changed. However, you should still update
at regular intervals to avoid making changes that don't work in
conjuction with changes that someone else made. Keeping an eye on
what goes by on the mailing list can help here.
* When you're happy that your change isn't going to break anything,
check it in. For a one-file change:
$ cvs commit <filename>
CVS will then pop up an editor for you to enter a "commit message",
this is just a short description of what your change does, and will
be kept in the history of the file.
If you're using emacs, simply load up the file into a buffer and type
C-x C-q, and emacs will prompt for a commit message and then check in
the file for you.
For a multiple-file change, things are a bit trickier. There are
several ways to do this, but this is the way I find easiest.
First type the commit message into a temporary file. Then either
$ cvs commit -F <commit-message> <file_1> .... <file_n>
or, if nothing else has changed in this part of the source tree,
$ cvs commit -F <commit-message> <directory>
where <directory> is a common parent directory for all your changes,
and <commit-message> is the name of the file containing the commit
message.
Shortly afterwards, you'll get some mail from the relevant mailing
list saying which files changed, and giving the commit message.
For a multiple-file change, you should still get only *one* message.
Updating Your Source Tree
-------------------------
It can be tempting to cvs update just part of a source tree to bring
in some changes that someone else has made, or before committing your
own changes. This is NOT RECOMMENDED! Quite often changes in one
part of the tree are dependent on changes in another part of the tree
(the mk/*.mk files are a good example where problems crop up quite
often). Having an inconsistent tree is a major cause of headaches.
So, to avoid a lot of hassle, follow this recipe for updating your
tree:
$ cd fptools
$ cvs update -Pd 2>&1 | tee log
Look at the log file, and fix any conflicts (denoted by a 'C' in the
first column). Next for every build tree you have pointing at this
source tree, you need to update the links in case any new files have
appeared:
$ cd <build-tree>
$ lndir <source-tree>
Some files might have been removed, so you need to remove the links
pointing to these non-existent files:
$ find . -xtype l -exec rm '{}' \;
And finally, re-configure to take into accound any changes in
mk/config.mk.in.
$ ./configure
To be *really* safe, you should do
$ gmake boot && gmake all
from the top-level, to update the dependencies and build any changed
files.
General Hints
-------------
* As a general rule: commit changes in small units, preferably
addressing one issue or implementing a single feature. Provide a
descriptive log message so that the repository records exactly which
changes were required to implement a given feature/fix a bug. I've
found this *very* useful in the past for finding out when a particular
bug was introduced: you can just wind back the CVS tree until
the bug disappears.
* Keep the sources at least *buildable* at any given time. No
doubt bugs will creep in, but it's quite easy to ensure that any
change made at least leaves the tree in a buildable state. We do
nightly builds of GHC to keep an eye on what things work/don't work
each day and how we're doing in relation to previous verions. This
idea is truely wrecked if the compiler won't build in the first place!
* To check out extra bits into an already-checked-out tree, use the
following procedure. Suppose you have a checked-out fptools tree containing
just ghc, and you want to add nofib to it:
cd fptools
cvs checkout nofib
or:
cd fptools
cvs update -d nofib
(the -d flag tells update to create a new directory). If you just want
part of the nofib suite, you can do
cd fptools
cvs checkout nofib/spectral
This works because 'nofib' is a module in its own right, and spectral
is a subdirectory of the nofib module. The path argument to checkout
must always start with a module name. There's no equivalent form of
this command using update.
Ok, that'll do for now. If there's anything else you'd like to see in
this file, just let me know.
Simon Marlow <simonm@dcs.gla.ac.uk>
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