How to check commit comments on SVN Commit

If you are using Subversion/CVS, you might have come across the issue where multiple developers working on a set of files are committing without any comments.

Subversion’s hook scripts provide a powerful way to associate actions with repository events. For example, the pre-commit hook allows you to check — and possibly abort — a transaction before it actually gets committed. I will provide you now two easy Unix bash scripts  that avoid bad developer behaviors:

• The first one “checkCommentNotEmpty.sh” is for checking that nobody submit an empty SVN commit comment
• The second one “checkCommentSyntax.sh” is able to enforce SVN commit comment pattern using regular expressions

Creating and Installing a Hook Script

Your Subversion repository already has some template hook scripts. For example, the pre-commit template is in PATH_TO_REPOS/hooks/pre-commit.tmpl. These templates contain instructions on what the hook script does and what parameters it can expect.

You can hook your own script on the following events

• start-commit Before the commit transaction starts
• pre-commit After the commit transaction starts but before the transaction is committed
• post-commit After the commit transaction completes
• pre-revprop-change Before a revision property is changed Repository Path,
• post-revprop-change: After a revision property is changed Repository Path
• pre-lock:  Before the lock being acquired
• post-lock:  After the lock being acquired

You’ll find examples in the hook directory named

• post-commit.tmpl
• pre-unlock.tmpl
• post-lock.tmpl
• pre-commit.tmpl
• start-commit.tmpl
• post-revprop-change.tmpl
• pre-lock.tmpl
• post-unlock.tmpl
• pre-revprop-change.tmpl

If you cant find them, brute force your server to locate them

# find / –name pre-commit

or

# locate pre-commit

On Debian you will find them at

/data/svn-repos/{yourRepository}/hooks

Create a file pre-commit with that content, nothing force you to put a huge bash script in pre-commit. In my example below, I prefer to divide pre-commit checks in multiple files. The pre-commit hook gives you a way to catch the transaction before it becomes a revision. Subversion passes this hook two parameters:

1. the path to the root of the repository
2. the transaction identifier

#!/bin/sh set -e /data/svn-repos/{yourRepository}/hooks/checkCommentNotEmpty.sh "$1" "$2" /data/svn-repos/{yourRepository}/hooks/checkCommentSyntax.sh "$1" "$2"

Note that after installation, every commit will run these two scripts. Check your permissions, scripts have to be runnable for the user (www-data on debian)

Avoid empty comment in SVN commits

Save this file in /data/svn-repos/{yourRepository}/hooks/checkCommentNotEmpty.sh

#!/bin/sh REPOS="$1" TXN="$2" SVNLOOK=/usr/bin/svnlook  if [`$SVNLOOK log -t $TXN $REPOS` != ""]; then   echo "" 1>&2   echo "*** Your commit has been blocked because you did not give any log message or your log message was too short." 1>&2   echo "Please write a log message describing the purpose of your changes and then try committing again." 1>&2   exit 1 else   exit 0 fi

Example in Eclipse, if you break the rule

Enforce SVN commit comment pattern using regular expressions

Save this file in /data/svn-repos/{yourRepository}/hooks/checkCommentSyntax.sh

This script use Bash script REGEX capabilities, I check against what could be a typical JIRA issues entry

If any developer try to use a commit statement not starting with for example PRODUCT-xxxx, the commit will be blocked.

#!/bin/sh REPOS="$1" TXN="$2" SVNLOOK=/usr/bin/svnlook regex="PRODUCT-[0-9]*"  if [[ `$SVNLOOK log -t $TXN $REPOS` =~ ${regex} ]]; then   exit 0 else   echo "" 1>&2   echo "*** Your commit has been blocked because you give an invalid commit comment" 1>&2   echo "Please make your commit comment start with PRODUCT-XXX" 1>&2  exit 1 fi

Example in Eclipse, if you break the rule

Want more?

You can automated code reviews with Checkstyle using pre-commit script and so Stop rule-breaking code before it enters your code base!

References

http://subversion.tigris.org/tools_contrib.html#hook_scripts List of some Hook scripts examples written in python/bash