simple example for git hooks

Does anyone have a simple example of a git pre-commit hook

I have difficulties finding understandable tutorals about git hooks.

What I am looking at is basic examples about

precommit hooks ================

- how get the commit comment and check it's contents
- how to get list of modified files

The issue I'm currently blocked with is rather simple.

I'd like to get a list aof all new or modified file names, such, that I can check, that for example all .h files contain a project specific header.

As soon as I have the file names I should be able to proceed.

How could I do this best from a shell script.

Is there any clear documentation about hich git commands I'm allowed to use during a trigger script and which ones I can't

Lateron I would be interested to implement a small server script, that refuses a git push in case, that the most recent commit in a branch would contain .h files without a certain header text

thanks for your help

On Thu, Sep 2, 2010 at 22:41, Gelonida <gelonida@gmail.com> wrote:

It's just a program that's run at a certain point, and its exit status determines if git proceeds.

So you can use any git command, but of course what you might affect what's about to be commited.

For a pre-commit hook (IIRC) you should find the stuff to be commited in the index, finding a list of things that changed from a hook is just a matter of diffing HEAD against the contents of the index then.

Him THanks a lot for your answer.

On 09/03/2010 12:49 AM, Ævar Arnfjörð Bjarmason wrote:

ok, so it seems what I'm missing is THE command to list all added / modified files I could of course use

git status

and parse its output, but this is probably not the right way to do.

I use git for quite some time, but don't know many commands except clone/pull/commit/reset/status/pull/push/cherrypick/rebase/tag/remote

thanks a lot for the typical way to identify added / modified files and for fetching the commit comment

On Friday 03 September 2010 00:54:44 Gelonida wrote:

Not unless you use the --porcelain option, which is explicitly meant to produce parsable output.

For instance, if "a" has staged modifications, "b" has unstaged modifications and "c" is added (and staged), you'll get

$ git status --porcelain    
M  a                                           
 M b                                           
A  c

i.e. the first character in a line denotes the difference between HEAD and index and the second character denotes the difference between index and working copy.

"Gelonida" <gelonida@gmail.com> wrote in message news:<i5p96s$u7q$1@dough.gmane.org>...

I think there is a special hook for this besides the pre-commit hook. Haven't tried it myself, yet. Look at githooks manpage in the reference manual.

I use this script to get modified files:

ABORTMSG="Commit Aborted!"

DIFFFILES=`git diff-index HEAD --cached --name-only SRC/*/* MYSRC/*` if [ $? -ne 0 ]; then

  echo "error running git diff-index command"

  echo $ABORTMSG

  exit 4

fi

Where SRC and MYSRC are the paths that contain the files I'm interested in. If you really want to list every thing that changed then don't specify paths.

I use this script to check the header:

for FILES in ${DIFFFILES}

  do

  echo "checking header for keywords in working copy of:${FILES}"

  if [ ! -r ${FILES} ]; then

    echo "${FILES} needs read permission"

    echo $ABORTMSG

    exit 6

  fi

  CHKHEADER=$(/usr/bin/head -n 2 ${FILES} | /bin/egrep -c 'somekeyword')

  if [ ${CHKHEADER} -ne 1 ]; then

    echo "line 1 or 2 needs those special keywords in it:${FILES}"

    echo $ABORTMSG

    exit 7

  fi

  done

THIS IS BASED ON THE ASSUMPTION THAT YOUR WORKING COPY AND INDEX ENTRY ARE SUPPOSED TO MATCH! Its based on a workflow in which you commit your current work. I you want to be able to git-add a file to the index and then modify the file again and then only commit what's in the index while retaining a working copy that differs from the index, THEN THIS SCRIPT WON'T WORK.

Keep in mind that git hooks don't allow you to prompt the user in your script. However, the exception may be git commands that prompt the user. Haven't tried that combination myself yet...

Your pre-commit hook will prevent this because you can only push commits. Unless you don't have control over what hooks the push-er is using in their repo... In which case there is a hook that checks push-ed content before committing it and will reject it if need be. Can't remember what it is offhand. Look at the githooks refmanual entry http://www.kernel.org/pub/software/scm/git/docs/v1.7.1.2/githooks.html for whatever git version you're using and you should be able to find it. These scripts would probably work in that remote-side hook.

v/r,

Neal

Hi everybody, On 09/03/2010 12:41 AM, Gelonida wrote:

Thanks for all your answers. I'm currently using git diff-index HEAD --cached

This seems to do what I was looking for.