Why svn2git causes loop to break in bash script?

Question

I am trying to migrate some modules from SVN to GIT using svn2git. I have a list of modules in .csv file like this:

pl.com.neokartgis.i18n;pl.com.neokartgis.i18n;test-gis;svniop
pl.com.neokartgis.cfg;pl.com.neokartgis.cfg;test-gis;svniop
pl.com.neokart.db;pl.com.neokart.db;test-gis;svniop

I want to migrate each module to separate GIT repository. I tried following script that reads list of modules from .csv file and import each module in a loop:

#!/bin/bash

LIST=$1
SVN_PATH=svn://svn.server/path/to/root
DIR=`pwd`

function importToGitModule {
    cd $DIR

    rm -rf /bigtmp/svn2git/repo
    mkdir /bigtmp/svn2git/repo
    cd /bigtmp/svn2git/repo
    svn2git --verbose $SVN_PATH/$1  
    #some other stuff with imported repository
}

cat $LIST | gawk -F";" '{ print $2; }' | while read module_to_import
do
    echo "before import $module_to_import"
    importToGitModule "$module_to_import";
done;

The problem is that the script ends after first iteration. However if I remove call to svn2git, script works as expected and prints message for each module in file.

My question is: why this script ends after first iteration and how can I change it to import all modules in a loop?

EDIT:

Following version of loop works correctly:

for module_to_import in `cat $LIST | gawk -F";" '{ print $2; }'`
do
    echo "before import $module_to_import"
    importToGitModule "$module_to_import";
done;

So why while read doesn't work?

Answer 1

I suspect that something inside your loop -- possibly part of the svn2git process -- is consuming stdin. Consider a loop like this:

ls /etc | while read file; do
    echo "filename: $file"
    cat > /tmp/data
done

Regardless of how many files are in /etc, this loop will only run once. The cat in this loop will consume all the other input on stdin.

You can see if you have encountered the same situation by explicitly redirecting stdin from /dev/null, like this:

cat $LIST | gawk -F";" '{ print $2; }' | while read module_to_import
do
    echo "before import $module_to_import"
    importToGitModule "$module_to_import" < /dev/null
done