#!/bin/sh
# PRE-REVPROP-CHANGE HOOK
#
# The pre-revprop-change hook is invoked before a revision property
# is added, modified or deleted. Subversion runs this hook by invoking
# a program (script, executable, binary, etc.) named 'pre-revprop-change'
# (for which this file is a template), with the following ordered
# arguments:
#
# [1] REPOS-PATH (the path to this repository)
# [2] REVISION (the revision being tweaked)
# [3] USER (the username of the person tweaking the property)
# [4] PROPNAME (the property being set on the revision)
# [5] ACTION (the property is being 'A'dded, 'M'odified, or 'D'eleted)
#
# [STDIN] PROPVAL ** the new property value is passed via STDIN.
#
# If the hook program exits with success, the propchange happens; but
# if it exits with failure (non-zero), the propchange doesn't happen.
# The hook program can use the 'svnlook' utility to examine the
# existing value of the revision property.
#
# WARNING: unlike other hooks, this hook MUST exist for revision
# properties to be changed. If the hook does not exist, Subversion
# will behave as if the hook were present, but failed. The reason
# for this is that revision properties are UNVERSIONED, meaning that
# a successful propchange is destructive; the old value is gone
# forever. We recommend the hook back up the old value somewhere.
#
# On a Unix system, the normal procedure is to have 'pre-revprop-change'
# invoke other programs to do the real work, though it may do the
# work itself too.
#
# Note that 'pre-revprop-change' must be executable by the user(s) who will
# invoke it (typically the user httpd runs as), and that user must
# have filesystem-level permission to access the repository.
#
# On a Windows system, you should name the hook program
# 'pre-revprop-change.bat' or 'pre-revprop-change.exe',
# but the basic idea is the same.
#
# The hook program typically does not inherit the environment of
# its parent process. For example, a common problem is for the
# PATH environment variable to not be set to its usual value, so
# that subprograms fail to launch unless invoked via absolute path.
# If you're having unexpected problems with a hook program, the
# culprit may be unusual (or missing) environment variables.
#
# Here is an example hook script, for a Unix /bin/sh interpreter.
# For more examples and pre-written hooks, see those in
# the Subversion repository at
# http://svn.collab.net/repos/svn/trunk/tools/hook-scripts/ and
# http://svn.collab.net/repos/svn/trunk/contrib/hook-scripts/
REPOS="$1"
REV="$2"
USER="$3"
PROPNAME="$4"
ACTION="$5"
if [ "$ACTION" = "M" -a "$PROPNAME" = "svn:log" ]; then exit 0; fi
echo "Changing revision properties other than svn:log is prohibited" >&2
exit 1
