Merge branch 'da/difftool'

* da/difftool:
  mergetool--lib: simplify API usage by removing more global variables
  Fix misspelled mergetool.keepBackup
  difftool/mergetool: refactor commands to use git-mergetool--lib
  mergetool: use $( ... ) instead of `backticks`
  bash completion: add git-difftool
  difftool: add support for a difftool.prompt config variable
  difftool: add various git-difftool tests
  difftool: move 'git-difftool' out of contrib
  difftool/mergetool: add diffuse as merge and diff tool
  difftool: add a -y shortcut for --no-prompt
  difftool: use perl built-ins when testing for msys
  difftool: remove the backup file feature
  difftool: remove merge options for opendiff, tkdiff, kdiff3 and xxdiff
  git-mergetool: add new merge tool TortoiseMerge
  git-mergetool/difftool: make (g)vimdiff workable under Windows
  doc/merge-config: list ecmerge as a built-in merge tool

4 files changed, 22 insertions, 431 deletions

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index c1c879821..1a90cb87f 100755
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -910,6 +910,26 @@ _git_diff ()
 	__git_complete_file
 }
 
+__git_mergetools_common="diffuse ecmerge emerge kdiff3 meld opendiff
+			tkdiff vimdiff gvimdiff xxdiff
+"
+
+_git_difftool ()
+{
+	local cur="${COMP_WORDS[COMP_CWORD]}"
+	case "$cur" in
+	--tool=*)
+		__gitcomp "$__git_mergetools_common kompare" "" "${cur##--tool=}"
+		return
+		;;
+	--*)
+		__gitcomp "--tool="
+		return
+		;;
+	esac
+	COMPREPLY=()
+}
+
 __git_fetch_options="
 	--quiet --verbose --append --upload-pack --force --keep --depth=
 	--tags --no-tags
@@ -1172,10 +1192,7 @@ _git_mergetool ()
 	local cur="${COMP_WORDS[COMP_CWORD]}"
 	case "$cur" in
 	--tool=*)
-		__gitcomp "
-			kdiff3 tkdiff meld xxdiff emerge
-			vimdiff gvimdiff ecmerge opendiff
-			" "" "${cur##--tool=}"
+		__gitcomp "$__git_mergetools_common tortoisemerge" "" "${cur##--tool=}"
 		return
 		;;
 	--*)
@@ -1901,6 +1918,7 @@ _git ()
 	config)      _git_config ;;
 	describe)    _git_describe ;;
 	diff)        _git_diff ;;
+	difftool)    _git_difftool ;;
 	fetch)       _git_fetch ;;
 	format-patch) _git_format_patch ;;
 	fsck)        _git_fsck ;;
diff --git a/contrib/difftool/git-difftool b/contrib/difftool/git-difftool
deleted file mode 100755
index 0deda3a0e..000000000
--- a/contrib/difftool/git-difftool
+++ /dev/null
@@ -1,73 +0,0 @@
-#!/usr/bin/env perl
-# Copyright (c) 2009 David Aguilar
-#
-# This is a wrapper around the GIT_EXTERNAL_DIFF-compatible
-# git-difftool-helper script.  This script exports
-# GIT_EXTERNAL_DIFF and GIT_PAGER for use by git, and
-# GIT_DIFFTOOL_NO_PROMPT and GIT_DIFF_TOOL for use by git-difftool-helper.
-# Any arguments that are unknown to this script are forwarded to 'git diff'.
-
-use strict;
-use warnings;
-use Cwd qw(abs_path);
-use File::Basename qw(dirname);
-
-my $DIR = abs_path(dirname($0));
-
-
-sub usage
-{
-	print << 'USAGE';
-usage: git difftool [--tool=<tool>] [--no-prompt] ["git diff" options]
-USAGE
-	exit 1;
-}
-
-sub setup_environment
-{
-	$ENV{PATH} = "$DIR:$ENV{PATH}";
-	$ENV{GIT_PAGER} = '';
-	$ENV{GIT_EXTERNAL_DIFF} = 'git-difftool-helper';
-}
-
-sub exe
-{
-	my $exe = shift;
-	return defined $ENV{COMSPEC} ? "$exe.exe" : $exe;
-}
-
-sub generate_command
-{
-	my @command = (exe('git'), 'diff');
-	my $skip_next = 0;
-	my $idx = -1;
-	for my $arg (@ARGV) {
-		$idx++;
-		if ($skip_next) {
-			$skip_next = 0;
-			next;
-		}
-		if ($arg eq '-t' or $arg eq '--tool') {
-			usage() if $#ARGV <= $idx;
-			$ENV{GIT_DIFF_TOOL} = $ARGV[$idx + 1];
-			$skip_next = 1;
-			next;
-		}
-		if ($arg =~ /^--tool=/) {
-			$ENV{GIT_DIFF_TOOL} = substr($arg, 7);
-			next;
-		}
-		if ($arg eq '--no-prompt') {
-			$ENV{GIT_DIFFTOOL_NO_PROMPT} = 'true';
-			next;
-		}
-		if ($arg eq '-h' or $arg eq '--help') {
-			usage();
-		}
-		push @command, $arg;
-	}
-	return @command
-}
-
-setup_environment();
-exec(generate_command());
diff --git a/contrib/difftool/git-difftool-helper b/contrib/difftool/git-difftool-helper
deleted file mode 100755
index 9c0a13452..000000000
--- a/contrib/difftool/git-difftool-helper
+++ /dev/null
@@ -1,249 +0,0 @@
-#!/bin/sh
-# git-difftool-helper is a GIT_EXTERNAL_DIFF-compatible diff tool launcher.
-# It supports kdiff3, kompare, tkdiff, xxdiff, meld, opendiff,
-# emerge, ecmerge, vimdiff, gvimdiff, and custom user-configurable tools.
-# This script is typically launched by using the 'git difftool'
-# convenience command.
-#
-# Copyright (c) 2009 David Aguilar
-
-# Set GIT_DIFFTOOL_NO_PROMPT to bypass the per-file prompt.
-should_prompt () {
-	! test -n "$GIT_DIFFTOOL_NO_PROMPT"
-}
-
-# Should we keep the backup .orig file?
-keep_backup_mode="$(git config --bool merge.keepBackup || echo true)"
-keep_backup () {
-	test "$keep_backup_mode" = "true"
-}
-
-# This function manages the backup .orig file.
-# A backup $MERGED.orig file is created if changes are detected.
-cleanup_temp_files () {
-	if test -n "$MERGED"; then
-		if keep_backup && test "$MERGED" -nt "$BACKUP"; then
-			test -f "$BACKUP" && mv -- "$BACKUP" "$MERGED.orig"
-		else
-			rm -f -- "$BACKUP"
-		fi
-	fi
-}
-
-# This is called when users Ctrl-C out of git-difftool-helper
-sigint_handler () {
-	cleanup_temp_files
-	exit 1
-}
-
-# This function prepares temporary files and launches the appropriate
-# merge tool.
-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"
-	ext="$$$(expr "$MERGED" : '.*\(\.[^/]*\)$')"
-	BACKUP="$MERGED.BACKUP.$ext"
-
-	# Create and ensure that we clean up $BACKUP
-	test -f "$MERGED" && cp -- "$MERGED" "$BACKUP"
-	trap sigint_handler INT
-
-	# $LOCAL and $REMOTE are temporary files so prompt
-	# the user with the real $MERGED name before launching $merge_tool.
-	if should_prompt; then
-		printf "\nViewing: '$MERGED'\n"
-		printf "Hit return to launch '%s': " "$merge_tool"
-		read ans
-	fi
-
-	# Run the appropriate merge tool command
-	case "$merge_tool" in
-	kdiff3)
-		basename=$(basename "$MERGED")
-		"$merge_tool_path" --auto \
-			--L1 "$basename (A)" \
-			--L2 "$basename (B)" \
-			-o "$MERGED" "$LOCAL" "$REMOTE" \
-			> /dev/null 2>&1
-		;;
-
-	kompare)
-		"$merge_tool_path" "$LOCAL" "$REMOTE"
-		;;
-
-	tkdiff)
-		"$merge_tool_path" -o "$MERGED" "$LOCAL" "$REMOTE"
-		;;
-
-	meld)
-		"$merge_tool_path" "$LOCAL" "$REMOTE"
-		;;
-
-	vimdiff)
-		"$merge_tool_path" -c "wincmd l" "$LOCAL" "$REMOTE"
-		;;
-
-	gvimdiff)
-		"$merge_tool_path" -c "wincmd l" -f "$LOCAL" "$REMOTE"
-		;;
-
-	xxdiff)
-		"$merge_tool_path" \
-			-X \
-			-R 'Accel.SaveAsMerged: "Ctrl-S"' \
-			-R 'Accel.Search: "Ctrl+F"' \
-			-R 'Accel.SearchForward: "Ctrl-G"' \
-			--merged-file "$MERGED" \
-			"$LOCAL" "$REMOTE"
-		;;
-
-	opendiff)
-		"$merge_tool_path" "$LOCAL" "$REMOTE" \
-			-merge "$MERGED" | cat
-		;;
-
-	ecmerge)
-		"$merge_tool_path" "$LOCAL" "$REMOTE" \
-			--default --mode=merge2 --to="$MERGED"
-		;;
-
-	emerge)
-		"$merge_tool_path" -f emerge-files-command \
-			"$LOCAL" "$REMOTE" "$(basename "$MERGED")"
-		;;
-
-	*)
-		if test -n "$merge_tool_cmd"; then
-			( eval $merge_tool_cmd )
-		fi
-		;;
-	esac
-
-	cleanup_temp_files
-}
-
-# Verifies that (difftool|mergetool).<tool>.cmd exists
-valid_custom_tool() {
-	merge_tool_cmd="$(git config difftool.$1.cmd)"
-	test -z "$merge_tool_cmd" &&
-	merge_tool_cmd="$(git config mergetool.$1.cmd)"
-	test -n "$merge_tool_cmd"
-}
-
-# Verifies that the chosen merge tool is properly setup.
-# Built-in merge tools are always valid.
-valid_tool() {
-	case "$1" in
-	kdiff3 | kompare | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
-		;; # happy
-	*)
-		if ! valid_custom_tool "$1"
-		then
-			return 1
-		fi
-		;;
-	esac
-}
-
-# Sets up the merge_tool_path variable.
-# This handles the difftool.<tool>.path configuration.
-# This also falls back to mergetool defaults.
-init_merge_tool_path() {
-	merge_tool_path=$(git config difftool."$1".path)
-	test -z "$merge_tool_path" &&
-	merge_tool_path=$(git config mergetool."$1".path)
-	if test -z "$merge_tool_path"; then
-		case "$1" in
-		emerge)
-			merge_tool_path=emacs
-			;;
-		*)
-			merge_tool_path="$1"
-			;;
-		esac
-	fi
-}
-
-# Allow GIT_DIFF_TOOL and GIT_MERGE_TOOL to provide default values
-test -n "$GIT_MERGE_TOOL" && merge_tool="$GIT_MERGE_TOOL"
-test -n "$GIT_DIFF_TOOL" && merge_tool="$GIT_DIFF_TOOL"
-
-# If merge tool was not specified then use the diff.tool
-# configuration variable.  If that's invalid then reset merge_tool.
-# Fallback to merge.tool.
-if test -z "$merge_tool"; then
-	merge_tool=$(git config diff.tool)
-	test -z "$merge_tool" &&
-	merge_tool=$(git config merge.tool)
-	if test -n "$merge_tool" && ! valid_tool "$merge_tool"; then
-		echo >&2 "git config option diff.tool set to unknown tool: $merge_tool"
-		echo >&2 "Resetting to default..."
-		unset merge_tool
-	fi
-fi
-
-# Try to guess an appropriate merge tool if no tool has been set.
-if test -z "$merge_tool"; then
-	# We have a $DISPLAY so try some common UNIX merge tools
-	if test -n "$DISPLAY"; then
-		# If gnome then prefer meld, otherwise, prefer kdiff3 or kompare
-		if test -n "$GNOME_DESKTOP_SESSION_ID" ; then
-			merge_tool_candidates="meld kdiff3 kompare tkdiff xxdiff gvimdiff"
-		else
-			merge_tool_candidates="kdiff3 kompare tkdiff xxdiff meld gvimdiff"
-		fi
-	fi
-	if echo "${VISUAL:-$EDITOR}" | grep 'emacs' > /dev/null 2>&1; then
-		# $EDITOR is emacs so add emerge as a candidate
-		merge_tool_candidates="$merge_tool_candidates emerge opendiff vimdiff"
-	elif echo "${VISUAL:-$EDITOR}" | grep 'vim' > /dev/null 2>&1; then
-		# $EDITOR is vim so add vimdiff as a candidate
-		merge_tool_candidates="$merge_tool_candidates vimdiff opendiff emerge"
-	else
-		merge_tool_candidates="$merge_tool_candidates opendiff emerge vimdiff"
-	fi
-	echo "merge tool candidates: $merge_tool_candidates"
-
-	# Loop over each candidate and stop when a valid merge tool is found.
-	for i in $merge_tool_candidates
-	do
-		init_merge_tool_path $i
-		if type "$merge_tool_path" > /dev/null 2>&1; then
-			merge_tool=$i
-			break
-		fi
-	done
-
-	if test -z "$merge_tool" ; then
-		echo "No known merge resolution program available."
-		exit 1
-	fi
-
-else
-	# A merge tool has been set, so verify that it's valid.
-	if ! valid_tool "$merge_tool"; then
-		echo >&2 "Unknown merge tool $merge_tool"
-		exit 1
-	fi
-
-	init_merge_tool_path "$merge_tool"
-
-	if test -z "$merge_tool_cmd" && ! type "$merge_tool_path" > /dev/null 2>&1; then
-		echo "The merge tool $merge_tool is not available as '$merge_tool_path'"
-		exit 1
-	fi
-fi
-
-
-# Launch the merge tool on each path provided by 'git diff'
-while test $# -gt 6
-do
-	launch_merge_tool "$1" "$2" "$5"
-	shift 7
-done
diff --git a/contrib/difftool/git-difftool.txt b/contrib/difftool/git-difftool.txt
deleted file mode 100644
index 2b7bc03ec..000000000
--- a/contrib/difftool/git-difftool.txt
+++ /dev/null
@@ -1,105 +0,0 @@
-git-difftool(1)
-===============
-
-NAME
-----
-git-difftool - compare changes using common merge tools
-
-SYNOPSIS
---------
-'git difftool' [--tool=<tool>] [--no-prompt] ['git diff' options]
-
-DESCRIPTION
------------
-'git-difftool' is a git command that allows you to compare and edit files
-between revisions using common merge tools.  At its most basic level,
-'git-difftool' does what 'git-mergetool' does but its use is for non-merge
-situations such as when preparing commits or comparing changes against
-the index.
-
-'git difftool' is a frontend to 'git diff' and accepts the same
-arguments and options.
-
-See linkgit:git-diff[1] for the full list of supported options.
-
-OPTIONS
--------
--t <tool>::
---tool=<tool>::
-	Use the merge resolution program specified by <tool>.
-	Valid merge tools are:
-	kdiff3, kompare, tkdiff, meld, xxdiff, emerge,
-	vimdiff, gvimdiff, ecmerge, and opendiff
-+
-If a merge resolution program is not specified, 'git-difftool'
-will use the configuration variable `diff.tool`.  If the
-configuration variable `diff.tool` is not set, 'git-difftool'
-will pick a suitable default.
-+
-You can explicitly provide a full path to the tool by setting the
-configuration variable `difftool.<tool>.path`. For example, you
-can configure the absolute path to kdiff3 by setting
-`difftool.kdiff3.path`. Otherwise, 'git-difftool' assumes the
-tool is available in PATH.
-+
-Instead of running one of the known merge tool programs,
-'git-difftool' can be customized to run an alternative program
-by specifying the command line to invoke in a configuration
-variable `difftool.<tool>.cmd`.
-+
-When 'git-difftool' is invoked with this tool (either through the
-`-t` or `--tool` option or the `diff.tool` configuration variable)
-the configured command line will be invoked with the following
-variables available: `$LOCAL` is set to the name of the temporary
-file containing the contents of the diff pre-image and `$REMOTE`
-is set to the name of the temporary file containing the contents
-of the diff post-image.  `$BASE` is provided for compatibility
-with custom merge tool commands and has the same value as `$LOCAL`.
-
---no-prompt::
-	Do not prompt before launching a diff tool.
-
-CONFIG VARIABLES
-----------------
-'git-difftool' falls back to 'git-mergetool' config variables when the
-difftool equivalents have not been defined.
-
-diff.tool::
-	The default merge tool to use.
-
-difftool.<tool>.path::
-	Override the path for the given tool.  This is useful in case
-	your tool is not in the PATH.
-
-difftool.<tool>.cmd::
-	Specify the command to invoke the specified merge tool.
-+
-See the `--tool=<tool>` option above for more details.
-
-merge.keepBackup::
-	The original, unedited file content can be saved to a file with
-	a `.orig` extension.  Defaults to `true` (i.e. keep the backup files).
-
-SEE ALSO
---------
-linkgit:git-diff[1]::
-	 Show changes between commits, commit and working tree, etc
-
-linkgit:git-mergetool[1]::
-	Run merge conflict resolution tools to resolve merge conflicts
-
-linkgit:git-config[1]::
-	 Get and set repository or global options
-
-
-AUTHOR
-------
-Written by David Aguilar <davvid@gmail.com>.
-
-Documentation
---------------
-Documentation by David Aguilar and the git-list <git@vger.kernel.org>.
-
-GIT
----
-Part of the linkgit:git[1] suite