vcprompt: version control information in your prompt

vcprompt is a little C program that prints a short string with barebones information about the current working directory for various version control systems. You configure your shell to include the output of vcprompt in your prompt, and you get version control information in your prompt.

vcprompt is designed to be small and lightweight rather than comprehensive. Currently, it has varying degrees of support for Mercurial, Git, Subversion, CVS, and Fossil working copies.

vcprompt has minimal dependencies: it does as much as it can with the standard C library and POSIX calls. It should work on any POSIX-compliant system with a C99 compiler. Some optional features require external libraries (see "Dependencies" below).

To build vcprompt from the source tarball:

./configure
make

If you're building in a source checkout, you also need GNU autoconf:

autoconf
./configure
make

(vcprompt requires GNU make, so if you are using a BSD variant where the default make is BSD make, you will need to install GNU make and run "gmake".)

To install it in your home directory:

make install PREFIX=$HOME

To make life easier for packagers, the Makefile also supports DESTDIR:

make install DESTDIR=/tmp/packageroot PREFIX=/usr

Please report build failures to the development mailing list, vcprompt-devel@googlegroups.com.

vcprompt includes a fairly comprehensive test suite. If you want to run it, see "Testing" below.

Dependencies

vcprompt requires GNU make to build.

vcprompt requires GNU autoconf to build from a source checkout (but not from a source tarball).

Support for Subversion >= 1.7 requires SQLite 3. If it's not present on the build system, vcprompt will support Subversion <= 1.6. Either way, the build should succeed and the tests should pass. To install the required files:

sudo apt-get install libsqlite3-dev   # Debian, Ubuntu
sudo yum install libsqlite3x-devel    # Fedora, Red Hat

If you have multiple versions of SQLite installed (this can be a problem on Mac OS X), you might need to specify the installation prefix of the one you want -- e.g., to use the brew package:

./configure --with-sqlite3=/usr/local

To see which features are built-in to your vcprompt binary, run

./vcprompt -F

Configuration

(For more details, see the man page.)

To use it with bash, just call it in PS1:

PS1='\u@\h $(vcprompt)\$ '

To use it with zsh, you need to enable shell option PROMPT_SUBST, and then do similarly to bash:

setopt prompt_subst
PROMPT='[%n@%m] [%~] $(vcprompt)'

Format Strings

You can customize the output of vcprompt using format strings, which can be specified either on the command line or in the VCPROMPT_FORMAT environment variable. For example:

vcprompt -f "%b"

and

VCPROMPT_FORMAT="%b" vcprompt

are equivalent.

Format strings use printf-like "%" escape sequences:

%n  name of the VC system managing the current directory
    (e.g. "cvs", "hg", "git", "svn")
%b  current branch name
%r  current revision
%u  ? if there are any unknown files
%m  + if there are any uncommitted changes (added, modified, or
    removed files)
%%  a single % character

All other characters are expanded as-is.

(For more details, see the man page.)

Testing

To run vcprompt's test suite:

make check

Test failures should be loud and obvious. Please report any test failures to the development mailing list:

vcprompt-devel@googlegroups.com.

To check for memory errors, you can run vcprompt's test suite under valgrind:

make grind

Obviously, this requires that you have valgrind installed.

Testing multiple versions of the same tool

Subversion changes its working copy format every couple of years, so vcprompt supports three formats: the pre-1.4 XML format, the 1.4..1.6 plain-text format, and the post-1.7 SQLite format. Actually testing these requires that you have different versions of Subversion on hand, each installed in a separate prefix.

For example, I keep multiple versions in /usr/local/subversion-1.x, so I can test them like this:

rm -f tests/svn-repo*.tar && make check-svn TOOLPATH=/usr/local/subversion-1.6/bin
rm -f tests/svn-repo*.tar && make check-svn TOOLPATH=/usr/local/subversion-1.7/bin

Actually building multiple versions of Subversion is harder than you would believe. (In fact, I've been unable to build anything older than 1.5, so vcprompt's support for pre-1.4 working copies is currently untested.)

TOOLPATH is supported for all tools; I also keep multiple versions of Mercurial around, so I can test vcprompt against them:

rm -f tests/hg-repo.tar && make check-svn TOOLPATH=/usr/local/mercurial-2.4/bin
rm -f tests/hg-repo.tar && make check-svn TOOLPATH=/usr/local/mercurial-2.5/bin
[...etc...]

Contributing

Patches are welcome. Please follow these guidelines:

Ensure that the tests pass before and after your patch. To run the tests quickly:
```
make check
```
To run the tests using valgrind (detect memory leaks):
```
make grind
```
If you cannot run the tests on a POSIX-compliant system, that is a bug: please let me know.
If at all possible, add a test whenever you fix a bug or implement a feature. If you can write a test that has no dependencies (e.g. no need to execute "git" or "hg" or whatever), add it to tests/test-simple. Otherwise, add it to the appropriate VC-specific test script, e.g. tests/test-git if it needs to be able to run git.
Keep the dependencies minimal: preferably just C99 and POSIX. If you need to run an external executable, make sure it makes sense: e.g. it's OK to run "git" in a git working directory, but only if we already know we are in a git working directory.
Performance matters! I wrote vcprompt so that people wouldn't have to spawn and initialize an entire Python or Perl interpreter every time they get a new shell prompt. Using system() to turn around and spawn external commands -- especially ones that involve a relatively large runtime penalty like Python scripts -- misses the point of vcprompt.

In fact, you'll find that vcprompt contains hacky little reimplementations of select bits and pieces of Mercurial, git, Subversion, and CVS precisely in order to avoid running external commands. (And, in the case of Subversion, to avoid depending on a large, complex library.)
Stick with my coding style:
- 4 space indents
- no tabs
- curly braces on the same line except when defining a function
- C99 comments and variable declarations are OK, at least until someone complains that their compiler cannot handle them
Feel free to add yourself to the contributors list below. (If you don't do it, I'll probably forget.)

Author Contact

vcprompt was written by Greg Ward .

The latest version is available from either of my public Mercurial repositories:

http://hg.gerg.ca/vcprompt/

http://bitbucket.org/gward/vcprompt/

Other Contributors

In chronological order:

Daniel Serpell
Jannis Leidel
Yuya Nishihara
KOIE Hidetaka
Armin Ronacher
Jordi Fita
Gregg Lind
Jakob Kramer
Robson Roberto Souza Peixoto
Alexandre Carmel-Veilleux
Felix Eckhofer

Thanks to all!

Copyright & License

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

wfr / vcprompt