How can a custom merge tool get access to file shell variables?
I'm in a situation where I have to fairly regularly merge two different trees where multiple files are being simultaneously edited in both trees and whitespace in some of the files is different in both trees as well. I would like to be able to use git mergetool to walk me through resolving conflicts in merges. My preferred graphical merge tool is xxdiff but in 3-way mode it doesn't allow you to ignore whitespace while doing the diff, only while displaying. As a result, all these files appear to have one giant diff and separating out what has really changed is a giant pain. Since my use-case is simple, I thought I would create a custom mergetool as a shell script that invokes xxdiff in 2-way mode and moves around files to get what I need. I've pasted that script at the end of the message.
I've added this script as custom mergetool as indicated in comments at the top of the script, but it does not work. It appears to me that the problem is that the shell variables containing the required filenames (BASE, LOCAL, REMOTE, MERGED) are not set. Looking at /usr/bin/git-mergetool, it appears that custom merge tools are called without arguments in a subshell and those variables are not exported anywhere so they are not in the environment of the subshell. Given this, how can a custom mergetool ever get access to this information to do its work?
If there is another better way to try to accomplish this (other than forcing whitespace to be the same in both trees for now!) I'd appreciate it if someone would clue me in!
--- Keith
#!/bin/bash # # Perform a merge for GIT in which whitespace is ignored. Because the # underlying diff tools don't seem to be able to ignore whitespace on # a three-way merge, a 2-way merge is done where the first file is a # copy of the remote file to be merged and the second file is copy of # the current file from the branch into which files are being merged. # The success of the merge is determined by whether a merged file is # written out from xxdiff. If you don't save the merged file, the # merge will be aborted. # # This script should be configured as a merge tool in git as follows: # # git-config --global --add mergetool.xxdiff-2way-ignorews.cmd xxdiff-2way-ignorews-git-mergetool # git-config --global --add mergetool.xxdiff-2way-ignorews.trustExitCode true #
rtmpfile="" ltmpfile=""
function remove_tmpfiles () {
if [ -n "$ltmpfile" ]; then
rm -f "$ltmpfile"
fi
if [ -n "$rtmpfile" ]; then
rm -f "$rtmpfile"
rm -f "$rtmpfile.merge"
fi
}function die () {
printf "%b" "$1"
remove_tmpfiles
exit 1
}[ -f "$LOCAL" ] || die "Local file does not exists: $LOCAL\n" [ -f "$REMOTE" ] || die "Remote file does not exists: $REMOTE\n"
# Be really paranoid and copy git's temp files to new ones so we aren't # playing around with git's files... ltmpfile=$(mktemp --tmpdir xxdiff-2way-tmp.remote.XXXXXXXXXX) cp "$LOCAL" "$ltmpfile" || die "Could not copy local file to temporary merge file.\nLocal file is: $LOCAL\nTemporary merge file is: $ltmpfile \n"
rtmpfile=$(mktemp --tmpdir xxdiff-2way-tmp.local.XXXXXXXXXX) cp "$REMOTE" "$rtmpfile" || die "Could not copy remote file to temporary merge result file.\nLocal file is: $LOCAL\nTemporary merge file is: $tmpfile\n"
xxdiff -w "$rtmpfile" "$ltmpfile"
if [ -f "$rtmpfile.merge" ]; then
if [ -f "$MERGED" ]; then
printf "Merged file already exists, removing so merge result can
be renamed.\n"
rm -f "$MERGED"
fi
mv "$rtmpfile.merge" "$MERGED" || die "Could not rename merge result
to merged file: $MERGED\n"
remove_tmpfiles
else
die "Did not find merge output file from xxdiff, aborting merge.\n"
fi