Why would my SVN pre-commit hook work locally, but not on commit?

Question

I have the following pre-commit hook to use JavaScript Lint for checking JavaScript files before committing:

#!/bin/env bash

REPOS="$1"
TXN="$2"

ECHO=/bin/echo
GREP=/bin/grep
SED=/bin/sed

SVN=/usr/bin/svn
SVNLOOK=/usr/bin/svnlook
FILES_CHANGED=`$SVNLOOK changed -r$TXN $REPOS | $SED -e "s/^....//g"`

JSL=/usr/local/bin/jsl
JSL_CONF=/usr/local/etc/jsl.conf

for FILE in $FILES_CHANGED
do
        if $ECHO $FILE | $GREP "\.js$"
        then
                $SVN cat -r$TXN file://$REPOS/$FILE | $JSL -conf $JSL_CONF -stdin 1>&2
                JSL_ERROR_CODE=$?
                if [ $JSL_ERROR_CODE != 0 ]
                then
                        exit $JSL_ERROR_CODE
                fi
        fi
done

# If we got here, nothing is wrong.
exit 0

This code works locally as follows: ./pre-commit /my/svn/repo/location 6781 # the number is the transaction number

BUT it doesn't error correctly on svn commit.

I have already accounted for:

• There being no $PATH, I explicitly set all command paths.
• I am catching the correct error code from the jsl command for exit.
• I am pushing STDOUT to STDERR for the jsl command so it will be displayed in the commit fail.

What am I missing?

Yours,
Trevor

Answer 1

I discovered the answer after a long and winding road. Basically, in my script above I am using -r in my svn commands, but in a pre-commit hook you must use -t, not -r. The complete script is below:

#!/bin/sh

REPOS="$1"
TXN="$2"

ECHO=/bin/echo
GREP=/bin/grep
SED=/bin/sed

SVNLOOK=/usr/bin/svnlook
FILES_CHANGED=`$SVNLOOK changed -t$TXN $REPOS | $SED -e "s/^....//g"`

JSL=/usr/local/bin/jsl
JSL_CONF=/usr/local/etc/jsl.default.conf

for FILE in $FILES_CHANGED
do
    if $ECHO $FILE | $GREP "\.js$"
    then
        $SVNLOOK cat -t$TXN $REPOS $FILE | $JSL -conf $JSL_CONF -stdin -nologo 1>&2
        JSL_ERROR_CODE=$?
        if [ $JSL_ERROR_CODE != 0 ]
        then
            exit $JSL_ERROR_CODE
        fi
    fi
done

# If we got here, nothing is wrong.
exit 0

Answer 2

It is possible that one of the programs you're running expect some environment variables to be set.

From Repository Creation and Configuration:

For security reasons, the Subversion repository executes hook scripts with an empty environment—that is, no environment variables are set at all, not even $PATH or %PATH%. Because of this, a lot of administrators are baffled when their hook script runs fine by hand, but doesn't work when run by Subversion. Be sure to explicitly set environment variables in your hook and/or use absolute paths to programs.

Try to execute them locally without any environment variables set and see if that works.

I usually end up importing all my environment in the first line of my hook scripts:

source /home/username/.bash_profile

Answer 3

If the error you're looking for is coming from svn in the pipeline rather that jsl, then $? isn't going to contain the return code. Use ${PIPESTATUS[@]} instead. It's an array that contains the return codes of each member of the pipeline. A quick way to check for any unspecified failure would be:

$SVN cat -r$TXN file://$REPOS/$FILE | $JSL -conf $JSL_CONF -stdin 1>&2
[[ ! ${PIPESTATUS[@]} =~ 1 ]]
JSL_ERROR_CODE=$?
if [ $JSL_ERROR_CODE != 0 ]

or

$SVN cat -r$TXN file://$REPOS/$FILE | $JSL -conf $JSL_CONF -stdin 1>&2
[[ ${PIPESTATUS[@]} != *1* ]]
JSL_ERROR_CODE=$?
if [ $JSL_ERROR_CODE != 0 ]