git/git-difftool--helper.sh
John Keeping 45a4f5d9f9 difftool: always honor fatal error exit codes
At the moment difftool's "trust exit code" logic always suppresses the
exit status of the diff utility we invoke.  This is useful because we
don't want to exit just because diff returned "1" because the files
differ, but it's confusing if the shell returns an error because the
selected diff utility is not found.

POSIX specifies 127 as the exit status for "command not found", 126 for
"command found but is not executable" and values greater than 128 if the
command terminated because it received a signal [1] and at least bash
and dash follow this specification, while diff utilities generally use
"1" for the exit status we want to ignore.

Handle any value of 126 or greater as a special value indicating that
some form of fatal error occurred.

[1] http://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_08_02

Signed-off-by: John Keeping <john@keeping.me.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-08-15 15:24:05 -07:00

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#!/bin/sh
# git-difftool--helper is a GIT_EXTERNAL_DIFF-compatible diff tool launcher.
# This script is typically launched by using the 'git difftool'
# convenience command.
#
# Copyright (c) 2009, 2010 David Aguilar
TOOL_MODE=diff
. git-mergetool--lib
# difftool.prompt controls the default prompt/no-prompt behavior
# and is overridden with $GIT_DIFFTOOL*_PROMPT.
should_prompt () {
prompt_merge=$(git config --bool mergetool.prompt || echo true)
prompt=$(git config --bool difftool.prompt || echo $prompt_merge)
if test "$prompt" = true
then
test -z "$GIT_DIFFTOOL_NO_PROMPT"
else
test -n "$GIT_DIFFTOOL_PROMPT"
fi
}
# Indicates that --extcmd=... was specified
use_ext_cmd () {
test -n "$GIT_DIFFTOOL_EXTCMD"
}
launch_merge_tool () {
# Merged is the filename as it appears in the work tree
# Local is the contents of a/filename
# Remote is the contents of b/filename
# Custom merge tool commands might use $BASE so we provide it
MERGED="$1"
LOCAL="$2"
REMOTE="$3"
BASE="$1"
# $LOCAL and $REMOTE are temporary files so prompt
# the user with the real $MERGED name before launching $merge_tool.
if should_prompt
then
printf "\nViewing (%s/%s): '%s'\n" "$GIT_DIFF_PATH_COUNTER" \
"$GIT_DIFF_PATH_TOTAL" "$MERGED"
if use_ext_cmd
then
printf "Launch '%s' [Y/n]? " \
"$GIT_DIFFTOOL_EXTCMD"
else
printf "Launch '%s' [Y/n]? " "$merge_tool"
fi
read ans || return
if test "$ans" = n
then
return
fi
fi
if use_ext_cmd
then
export BASE
eval $GIT_DIFFTOOL_EXTCMD '"$LOCAL"' '"$REMOTE"'
else
run_merge_tool "$merge_tool"
fi
}
if ! use_ext_cmd
then
if test -n "$GIT_DIFF_TOOL"
then
merge_tool="$GIT_DIFF_TOOL"
else
merge_tool="$(get_merge_tool)" || exit
fi
fi
if test -n "$GIT_DIFFTOOL_DIRDIFF"
then
LOCAL="$1"
REMOTE="$2"
run_merge_tool "$merge_tool" false
else
# Launch the merge tool on each path provided by 'git diff'
while test $# -gt 6
do
launch_merge_tool "$1" "$2" "$5"
status=$?
if test $status -ge 126
then
# Command not found (127), not executable (126) or
# exited via a signal (>= 128).
exit $status
fi
if test "$status" != 0 &&
test "$GIT_DIFFTOOL_TRUST_EXIT_CODE" = true
then
exit $status
fi
shift 7
done
fi
exit 0