push options: pass push options to the transport helper
[gitweb.git] / git-mergetool.sh
index d4078a6affd9b4c1fa52e6dba0fe6c151fa452dc..c062e3de3a503bd01203f2a6aef63eea63cae5c5 100755 (executable)
 # This program resolves merge conflicts in git
 #
 # Copyright (c) 2006 Theodore Y. Ts'o
+# Copyright (c) 2009-2016 David Aguilar
 #
 # This file is licensed under the GPL v2, or a later version
 # at the discretion of Junio C Hamano.
 #
 
-USAGE='[--tool=tool] [file to merge] ...'
+USAGE='[--tool=tool] [--tool-help] [-y|--no-prompt|--prompt] [-O<orderfile>] [file to merge] ...'
 SUBDIRECTORY_OK=Yes
+NONGIT_OK=Yes
 OPTIONS_SPEC=
+TOOL_MODE=merge
 . git-sh-setup
-require_work_tree
-prefix=$(git rev-parse --show-prefix)
+. git-mergetool--lib
 
 # Returns true if the mode reflects a symlink
 is_symlink () {
-    test "$1" = 120000
+       test "$1" = 120000
+}
+
+is_submodule () {
+       test "$1" = 160000
 }
 
 local_present () {
-    test -n "$local_mode"
+       test -n "$local_mode"
 }
 
 remote_present () {
-    test -n "$remote_mode"
+       test -n "$remote_mode"
 }
 
 base_present () {
-    test -n "$base_mode"
+       test -n "$base_mode"
+}
+
+mergetool_tmpdir_init () {
+       if test "$(git config --bool mergetool.writeToTemp)" != true
+       then
+               MERGETOOL_TMPDIR=.
+               return 0
+       fi
+       if MERGETOOL_TMPDIR=$(mktemp -d -t "git-mergetool-XXXXXX" 2>/dev/null)
+       then
+               return 0
+       fi
+       die "error: mktemp is needed when 'mergetool.writeToTemp' is true"
 }
 
 cleanup_temp_files () {
-    if test "$1" = --save-backup ; then
-       mv -- "$BACKUP" "$MERGED.orig"
-       rm -f -- "$LOCAL" "$REMOTE" "$BASE"
-    else
-       rm -f -- "$LOCAL" "$REMOTE" "$BASE" "$BACKUP"
-    fi
+       if test "$1" = --save-backup
+       then
+               rm -rf -- "$MERGED.orig"
+               test -e "$BACKUP" && mv -- "$BACKUP" "$MERGED.orig"
+               rm -f -- "$LOCAL" "$REMOTE" "$BASE"
+       else
+               rm -f -- "$LOCAL" "$REMOTE" "$BASE" "$BACKUP"
+       fi
+       if test "$MERGETOOL_TMPDIR" != "."
+       then
+               rmdir "$MERGETOOL_TMPDIR"
+       fi
 }
 
 describe_file () {
-    mode="$1"
-    branch="$2"
-    file="$3"
-
-    printf "  {%s}: " "$branch"
-    if test -z "$mode"; then
-       echo "deleted"
-    elif is_symlink "$mode" ; then
-       echo "a symbolic link -> '$(cat "$file")'"
-    else
-       if base_present; then
-           echo "modified"
+       mode="$1"
+       branch="$2"
+       file="$3"
+
+       printf "  {%s}: " "$branch"
+       if test -z "$mode"
+       then
+               echo "deleted"
+       elif is_symlink "$mode"
+       then
+               echo "a symbolic link -> '$(cat "$file")'"
+       elif is_submodule "$mode"
+       then
+               echo "submodule commit $file"
+       elif base_present
+       then
+               echo "modified file"
        else
-           echo "created"
+               echo "created file"
        fi
-    fi
 }
 
-
 resolve_symlink_merge () {
-    while true; do
-       printf "Use (l)ocal or (r)emote, or (a)bort? "
-       read ans
-       case "$ans" in
-           [lL]*)
-               git checkout-index -f --stage=2 -- "$MERGED"
-               git add -- "$MERGED"
-               cleanup_temp_files --save-backup
-               return
-               ;;
-           [rR]*)
-               git checkout-index -f --stage=3 -- "$MERGED"
-               git add -- "$MERGED"
-               cleanup_temp_files --save-backup
-               return
-               ;;
-           [aA]*)
-               exit 1
-               ;;
-           esac
+       while true
+       do
+               printf "Use (l)ocal or (r)emote, or (a)bort? "
+               read ans || return 1
+               case "$ans" in
+               [lL]*)
+                       git checkout-index -f --stage=2 -- "$MERGED"
+                       git add -- "$MERGED"
+                       cleanup_temp_files --save-backup
+                       return 0
+                       ;;
+               [rR]*)
+                       git checkout-index -f --stage=3 -- "$MERGED"
+                       git add -- "$MERGED"
+                       cleanup_temp_files --save-backup
+                       return 0
+                       ;;
+               [aA]*)
+                       return 1
+                       ;;
+               esac
        done
 }
 
 resolve_deleted_merge () {
-    while true; do
-       if base_present; then
-           printf "Use (m)odified or (d)eleted file, or (a)bort? "
-       else
-           printf "Use (c)reated or (d)eleted file, or (a)bort? "
-       fi
-       read ans
-       case "$ans" in
-           [mMcC]*)
-               git add -- "$MERGED"
-               cleanup_temp_files --save-backup
-               return
-               ;;
-           [dD]*)
-               git rm -- "$MERGED" > /dev/null
-               cleanup_temp_files
-               return
-               ;;
-           [aA]*)
-               exit 1
-               ;;
-           esac
+       while true
+       do
+               if base_present
+               then
+                       printf "Use (m)odified or (d)eleted file, or (a)bort? "
+               else
+                       printf "Use (c)reated or (d)eleted file, or (a)bort? "
+               fi
+               read ans || return 1
+               case "$ans" in
+               [mMcC]*)
+                       git add -- "$MERGED"
+                       if test "$merge_keep_backup" = "true"
+                       then
+                               cleanup_temp_files --save-backup
+                       else
+                               cleanup_temp_files
+                       fi
+                       return 0
+                       ;;
+               [dD]*)
+                       git rm -- "$MERGED" > /dev/null
+                       cleanup_temp_files
+                       return 0
+                       ;;
+               [aA]*)
+                       if test "$merge_keep_temporaries" = "false"
+                       then
+                               cleanup_temp_files
+                       fi
+                       return 1
+                       ;;
+               esac
        done
 }
 
-check_unchanged () {
-    if test "$MERGED" -nt "$BACKUP" ; then
-       status=0;
-    else
-       while true; do
-           echo "$MERGED seems unchanged."
-           printf "Was the merge successful? [y/n] "
-           read answer < /dev/tty
-           case "$answer" in
-               y*|Y*) status=0; break ;;
-               n*|N*) status=1; break ;;
-           esac
+resolve_submodule_merge () {
+       while true
+       do
+               printf "Use (l)ocal or (r)emote, or (a)bort? "
+               read ans || return 1
+               case "$ans" in
+               [lL]*)
+                       if ! local_present
+                       then
+                               if test -n "$(git ls-tree HEAD -- "$MERGED")"
+                               then
+                                       # Local isn't present, but it's a subdirectory
+                                       git ls-tree --full-name -r HEAD -- "$MERGED" |
+                                       git update-index --index-info || exit $?
+                               else
+                                       test -e "$MERGED" && mv -- "$MERGED" "$BACKUP"
+                                       git update-index --force-remove "$MERGED"
+                                       cleanup_temp_files --save-backup
+                               fi
+                       elif is_submodule "$local_mode"
+                       then
+                               stage_submodule "$MERGED" "$local_sha1"
+                       else
+                               git checkout-index -f --stage=2 -- "$MERGED"
+                               git add -- "$MERGED"
+                       fi
+                       return 0
+                       ;;
+               [rR]*)
+                       if ! remote_present
+                       then
+                               if test -n "$(git ls-tree MERGE_HEAD -- "$MERGED")"
+                               then
+                                       # Remote isn't present, but it's a subdirectory
+                                       git ls-tree --full-name -r MERGE_HEAD -- "$MERGED" |
+                                       git update-index --index-info || exit $?
+                               else
+                                       test -e "$MERGED" && mv -- "$MERGED" "$BACKUP"
+                                       git update-index --force-remove "$MERGED"
+                               fi
+                       elif is_submodule "$remote_mode"
+                       then
+                               ! is_submodule "$local_mode" &&
+                               test -e "$MERGED" &&
+                               mv -- "$MERGED" "$BACKUP"
+                               stage_submodule "$MERGED" "$remote_sha1"
+                       else
+                               test -e "$MERGED" && mv -- "$MERGED" "$BACKUP"
+                               git checkout-index -f --stage=3 -- "$MERGED"
+                               git add -- "$MERGED"
+                       fi
+                       cleanup_temp_files --save-backup
+                       return 0
+                       ;;
+               [aA]*)
+                       return 1
+                       ;;
+               esac
        done
-    fi
+}
+
+stage_submodule () {
+       path="$1"
+       submodule_sha1="$2"
+       mkdir -p "$path" ||
+       die "fatal: unable to create directory for module at $path"
+       # Find $path relative to work tree
+       work_tree_root=$(cd_to_toplevel && pwd)
+       work_rel_path=$(cd "$path" &&
+               GIT_WORK_TREE="${work_tree_root}" git rev-parse --show-prefix
+       )
+       test -n "$work_rel_path" ||
+       die "fatal: unable to get path of module $path relative to work tree"
+       git update-index --add --replace --cacheinfo 160000 "$submodule_sha1" "${work_rel_path%/}" || die
+}
+
+checkout_staged_file () {
+       tmpfile=$(expr \
+               "$(git checkout-index --temp --stage="$1" "$2" 2>/dev/null)" \
+               : '\([^ ]*\)    ')
+
+       if test $? -eq 0 && test -n "$tmpfile"
+       then
+               mv -- "$(git rev-parse --show-cdup)$tmpfile" "$3"
+       else
+               >"$3"
+       fi
 }
 
 merge_file () {
-    MERGED="$1"
+       MERGED="$1"
+
+       f=$(git ls-files -u -- "$MERGED")
+       if test -z "$f"
+       then
+               if test ! -f "$MERGED"
+               then
+                       echo "$MERGED: file not found"
+               else
+                       echo "$MERGED: file does not need merging"
+               fi
+               return 1
+       fi
 
-    f=`git ls-files -u -- "$MERGED"`
-    if test -z "$f" ; then
-       if test ! -f "$MERGED" ; then
-           echo "$MERGED: file not found"
+       if BASE=$(expr "$MERGED" : '\(.*\)\.[^/]*$')
+       then
+               ext=$(expr "$MERGED" : '.*\(\.[^/]*\)$')
        else
-           echo "$MERGED: file does not need merging"
+               BASE=$MERGED
+               ext=
        fi
-       exit 1
-    fi
 
-    ext="$$$(expr "$MERGED" : '.*\(\.[^/]*\)$')"
-    BACKUP="./$MERGED.BACKUP.$ext"
-    LOCAL="./$MERGED.LOCAL.$ext"
-    REMOTE="./$MERGED.REMOTE.$ext"
-    BASE="./$MERGED.BASE.$ext"
+       mergetool_tmpdir_init
 
-    mv -- "$MERGED" "$BACKUP"
-    cp -- "$BACKUP" "$MERGED"
+       if test "$MERGETOOL_TMPDIR" != "."
+       then
+               # If we're using a temporary directory then write to the
+               # top-level of that directory.
+               BASE=${BASE##*/}
+       fi
 
-    base_mode=`git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}'`
-    local_mode=`git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}'`
-    remote_mode=`git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $1;}'`
+       BACKUP="$MERGETOOL_TMPDIR/${BASE}_BACKUP_$$$ext"
+       LOCAL="$MERGETOOL_TMPDIR/${BASE}_LOCAL_$$$ext"
+       REMOTE="$MERGETOOL_TMPDIR/${BASE}_REMOTE_$$$ext"
+       BASE="$MERGETOOL_TMPDIR/${BASE}_BASE_$$$ext"
+
+       base_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}')
+       local_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}')
+       remote_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $1;}')
+
+       if is_submodule "$local_mode" || is_submodule "$remote_mode"
+       then
+               echo "Submodule merge conflict for '$MERGED':"
+               local_sha1=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $2;}')
+               remote_sha1=$(git ls-files -u -- "$MERGED" | awk '{if ($3==3) print $2;}')
+               describe_file "$local_mode" "local" "$local_sha1"
+               describe_file "$remote_mode" "remote" "$remote_sha1"
+               resolve_submodule_merge
+               return
+       fi
 
-    base_present   && git cat-file blob ":1:$prefix$MERGED" >"$BASE" 2>/dev/null
-    local_present  && git cat-file blob ":2:$prefix$MERGED" >"$LOCAL" 2>/dev/null
-    remote_present && git cat-file blob ":3:$prefix$MERGED" >"$REMOTE" 2>/dev/null
+       if test -f "$MERGED"
+       then
+               mv -- "$MERGED" "$BACKUP"
+               cp -- "$BACKUP" "$MERGED"
+       fi
+       # Create a parent directory to handle delete/delete conflicts
+       # where the base's directory no longer exists.
+       mkdir -p "$(dirname "$MERGED")"
+
+       checkout_staged_file 1 "$MERGED" "$BASE"
+       checkout_staged_file 2 "$MERGED" "$LOCAL"
+       checkout_staged_file 3 "$MERGED" "$REMOTE"
+
+       if test -z "$local_mode" || test -z "$remote_mode"
+       then
+               echo "Deleted merge conflict for '$MERGED':"
+               describe_file "$local_mode" "local" "$LOCAL"
+               describe_file "$remote_mode" "remote" "$REMOTE"
+               resolve_deleted_merge
+               status=$?
+               rmdir -p "$(dirname "$MERGED")" 2>/dev/null
+               return $status
+       fi
 
-    if test -z "$local_mode" -o -z "$remote_mode"; then
-       echo "Deleted merge conflict for '$MERGED':"
-       describe_file "$local_mode" "local" "$LOCAL"
-       describe_file "$remote_mode" "remote" "$REMOTE"
-       resolve_deleted_merge
-       return
-    fi
+       if is_symlink "$local_mode" || is_symlink "$remote_mode"
+       then
+               echo "Symbolic link merge conflict for '$MERGED':"
+               describe_file "$local_mode" "local" "$LOCAL"
+               describe_file "$remote_mode" "remote" "$REMOTE"
+               resolve_symlink_merge
+               return
+       fi
 
-    if is_symlink "$local_mode" || is_symlink "$remote_mode"; then
-       echo "Symbolic link merge conflict for '$MERGED':"
+       echo "Normal merge conflict for '$MERGED':"
        describe_file "$local_mode" "local" "$LOCAL"
        describe_file "$remote_mode" "remote" "$REMOTE"
-       resolve_symlink_merge
-       return
-    fi
-
-    echo "Normal merge conflict for '$MERGED':"
-    describe_file "$local_mode" "local" "$LOCAL"
-    describe_file "$remote_mode" "remote" "$REMOTE"
-    printf "Hit return to start merge resolution tool (%s): " "$merge_tool"
-    read ans
-
-    case "$merge_tool" in
-       kdiff3)
-           if base_present ; then
-               ("$merge_tool_path" --auto --L1 "$MERGED (Base)" --L2 "$MERGED (Local)" --L3 "$MERGED (Remote)" \
-                   -o "$MERGED" "$BASE" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
-           else
-               ("$merge_tool_path" --auto --L1 "$MERGED (Local)" --L2 "$MERGED (Remote)" \
-                   -o "$MERGED" "$LOCAL" "$REMOTE" > /dev/null 2>&1)
-           fi
-           status=$?
-           ;;
-       tkdiff)
-           if base_present ; then
-               "$merge_tool_path" -a "$BASE" -o "$MERGED" "$LOCAL" "$REMOTE"
-           else
-               "$merge_tool_path" -o "$MERGED" "$LOCAL" "$REMOTE"
-           fi
-           status=$?
-           ;;
-       meld|vimdiff)
-           touch "$BACKUP"
-           "$merge_tool_path" "$LOCAL" "$MERGED" "$REMOTE"
-           check_unchanged
-           ;;
-       gvimdiff)
-           touch "$BACKUP"
-           "$merge_tool_path" -f "$LOCAL" "$MERGED" "$REMOTE"
-           check_unchanged
-           ;;
-       xxdiff)
-           touch "$BACKUP"
-           if base_present ; then
-               "$merge_tool_path" -X --show-merged-pane \
-                   -R 'Accel.SaveAsMerged: "Ctrl-S"' \
-                   -R 'Accel.Search: "Ctrl+F"' \
-                   -R 'Accel.SearchForward: "Ctrl-G"' \
-                   --merged-file "$MERGED" "$LOCAL" "$BASE" "$REMOTE"
-           else
-               "$merge_tool_path" -X --show-merged-pane \
-                   -R 'Accel.SaveAsMerged: "Ctrl-S"' \
-                   -R 'Accel.Search: "Ctrl+F"' \
-                   -R 'Accel.SearchForward: "Ctrl-G"' \
-                   --merged-file "$MERGED" "$LOCAL" "$REMOTE"
-           fi
-           check_unchanged
-           ;;
-       opendiff)
-           touch "$BACKUP"
-           if base_present; then
-               "$merge_tool_path" "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$MERGED" | cat
-           else
-               "$merge_tool_path" "$LOCAL" "$REMOTE" -merge "$MERGED" | cat
-           fi
-           check_unchanged
-           ;;
-       ecmerge)
-           touch "$BACKUP"
-           if base_present; then
-               "$merge_tool_path" "$BASE" "$LOCAL" "$REMOTE" --default --mode=merge3 --to="$MERGED"
-           else
-               "$merge_tool_path" "$LOCAL" "$REMOTE" --default --mode=merge2 --to="$MERGED"
-           fi
-           check_unchanged
-           ;;
-       emerge)
-           if base_present ; then
-               "$merge_tool_path" -f emerge-files-with-ancestor-command "$LOCAL" "$REMOTE" "$BASE" "$(basename "$MERGED")"
-           else
-               "$merge_tool_path" -f emerge-files-command "$LOCAL" "$REMOTE" "$(basename "$MERGED")"
-           fi
-           status=$?
-           ;;
-       *)
-           if test -n "$merge_tool_cmd"; then
-               if test "$merge_tool_trust_exit_code" = "false"; then
-                   touch "$BACKUP"
-                   ( eval $merge_tool_cmd )
-                   check_unchanged
-               else
-                   ( eval $merge_tool_cmd )
-                   status=$?
+       if test "$guessed_merge_tool" = true || test "$prompt" = true
+       then
+               printf "Hit return to start merge resolution tool (%s): " "$merge_tool"
+               read ans || return 1
+       fi
+
+       if base_present
+       then
+               present=true
+       else
+               present=false
+       fi
+
+       if ! run_merge_tool "$merge_tool" "$present"
+       then
+               echo "merge of $MERGED failed" 1>&2
+               mv -- "$BACKUP" "$MERGED"
+
+               if test "$merge_keep_temporaries" = "false"
+               then
+                       cleanup_temp_files
                fi
-           fi
-           ;;
-    esac
-    if test "$status" -ne 0; then
-       echo "merge of $MERGED failed" 1>&2
-       mv -- "$BACKUP" "$MERGED"
-       exit 1
-    fi
-
-    if test "$merge_keep_backup" = "true"; then
-       mv -- "$BACKUP" "$MERGED.orig"
-    else
-       rm -- "$BACKUP"
-    fi
-
-    git add -- "$MERGED"
-    cleanup_temp_files
-}
 
-while test $# != 0
-do
-    case "$1" in
-       -t|--tool*)
-           case "$#,$1" in
-               *,*=*)
-                   merge_tool=`expr "z$1" : 'z-[^=]*=\(.*\)'`
-                   ;;
-               1,*)
-                   usage ;;
-               *)
-                   merge_tool="$2"
-                   shift ;;
-           esac
-           ;;
-       --)
-           shift
-           break
-           ;;
-       -*)
-           usage
-           ;;
-       *)
-           break
-           ;;
-    esac
-    shift
-done
-
-valid_custom_tool()
-{
-    merge_tool_cmd="$(git config mergetool.$1.cmd)"
-    test -n "$merge_tool_cmd"
+               return 1
+       fi
+
+       if test "$merge_keep_backup" = "true"
+       then
+               mv -- "$BACKUP" "$MERGED.orig"
+       else
+               rm -- "$BACKUP"
+       fi
+
+       git add -- "$MERGED"
+       cleanup_temp_files
+       return 0
 }
 
-valid_tool() {
-       case "$1" in
-               kdiff3 | tkdiff | xxdiff | meld | opendiff | emerge | vimdiff | gvimdiff | ecmerge)
-                       ;; # happy
-               *)
-                       if ! valid_custom_tool "$1"; then
-                               return 1
-                       fi
+prompt_after_failed_merge () {
+       while true
+       do
+               printf "Continue merging other unresolved paths [y/n]? "
+               read ans || return 1
+               case "$ans" in
+               [yY]*)
+                       return 0
                        ;;
-       esac
+               [nN]*)
+                       return 1
+                       ;;
+               esac
+       done
 }
 
-init_merge_tool_path() {
-       merge_tool_path=`git config mergetool.$1.path`
-       if test -z "$merge_tool_path" ; then
+print_noop_and_exit () {
+       echo "No files need merging"
+       exit 0
+}
+
+main () {
+       prompt=$(git config --bool mergetool.prompt)
+       guessed_merge_tool=false
+       orderfile=
+
+       while test $# != 0
+       do
                case "$1" in
-                       emerge)
-                               merge_tool_path=emacs
+               --tool-help=*)
+                       TOOL_MODE=${1#--tool-help=}
+                       show_tool_help
+                       ;;
+               --tool-help)
+                       show_tool_help
+                       ;;
+               -t|--tool*)
+                       case "$#,$1" in
+                       *,*=*)
+                               merge_tool=$(expr "z$1" : 'z-[^=]*=\(.*\)')
                                ;;
+                       1,*)
+                               usage ;;
                        *)
-                               merge_tool_path=$1
-                               ;;
+                               merge_tool="$2"
+                               shift ;;
+                       esac
+                       ;;
+               -y|--no-prompt)
+                       prompt=false
+                       ;;
+               --prompt)
+                       prompt=true
+                       ;;
+               -O*)
+                       orderfile="${1#-O}"
+                       ;;
+               --)
+                       shift
+                       break
+                       ;;
+               -*)
+                       usage
+                       ;;
+               *)
+                       break
+                       ;;
                esac
+               shift
+       done
+
+       git_dir_init
+       require_work_tree
+
+       if test -z "$merge_tool"
+       then
+               # Check if a merge tool has been configured
+               merge_tool=$(get_configured_merge_tool)
+               # Try to guess an appropriate merge tool if no tool has been set.
+               if test -z "$merge_tool"
+               then
+                       merge_tool=$(guess_merge_tool) || exit
+                       guessed_merge_tool=true
+               fi
+       fi
+       merge_keep_backup="$(git config --bool mergetool.keepBackup || echo true)"
+       merge_keep_temporaries="$(git config --bool mergetool.keepTemporaries || echo false)"
+
+       prefix=$(git rev-parse --show-prefix) || exit 1
+       cd_to_toplevel
+
+       if test -n "$orderfile"
+       then
+               orderfile=$(
+                       git rev-parse --prefix "$prefix" -- "$orderfile" |
+                       sed -e 1d
+               )
+       fi
+
+       if test $# -eq 0 && test -e "$GIT_DIR/MERGE_RR"
+       then
+               set -- $(git rerere remaining)
+               if test $# -eq 0
+               then
+                       print_noop_and_exit
+               fi
+       elif test $# -ge 0
+       then
+               # rev-parse provides the -- needed for 'set'
+               eval "set $(git rev-parse --sq --prefix "$prefix" -- "$@")"
        fi
-}
 
+       files=$(git -c core.quotePath=false \
+               diff --name-only --diff-filter=U \
+               ${orderfile:+"-O$orderfile"} -- "$@")
 
-if test -z "$merge_tool"; then
-    merge_tool=`git config merge.tool`
-    if test -n "$merge_tool" && ! valid_tool "$merge_tool"; then
-           echo >&2 "git config option merge.tool set to unknown tool: $merge_tool"
-           echo >&2 "Resetting to default..."
-           unset merge_tool
-    fi
-fi
-
-if test -z "$merge_tool" ; then
-    if test -n "$DISPLAY"; then
-        merge_tool_candidates="kdiff3 tkdiff xxdiff meld gvimdiff"
-        if test -n "$GNOME_DESKTOP_SESSION_ID" ; then
-            merge_tool_candidates="meld $merge_tool_candidates"
-        fi
-        if test "$KDE_FULL_SESSION" = "true"; then
-            merge_tool_candidates="kdiff3 $merge_tool_candidates"
-        fi
-    fi
-    if echo "${VISUAL:-$EDITOR}" | grep 'emacs' > /dev/null 2>&1; then
-        merge_tool_candidates="$merge_tool_candidates emerge"
-    fi
-    if echo "${VISUAL:-$EDITOR}" | grep 'vim' > /dev/null 2>&1; then
-        merge_tool_candidates="$merge_tool_candidates vimdiff"
-    fi
-    merge_tool_candidates="$merge_tool_candidates opendiff emerge vimdiff"
-    echo "merge tool candidates: $merge_tool_candidates"
-    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
-    if ! valid_tool "$merge_tool"; then
-        echo >&2 "Unknown merge_tool $merge_tool"
-        exit 1
-    fi
-
-    init_merge_tool_path "$merge_tool"
-
-    merge_keep_backup="$(git config --bool merge.keepBackup || echo true)"
-
-    if test -z "$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
-
-    if ! test -z "$merge_tool_cmd"; then
-        merge_tool_trust_exit_code="$(git config --bool mergetool.$merge_tool.trustExitCode || echo false)"
-    fi
-fi
-
-
-if test $# -eq 0 ; then
-       files=`git ls-files -u | sed -e 's/^[^  ]*      //' | sort -u`
-       if test -z "$files" ; then
-               echo "No files need merging"
-               exit 0
+       if test -z "$files"
+       then
+               print_noop_and_exit
        fi
-       echo Merging the files: "$files"
-       git ls-files -u |
-       sed -e 's/^[^   ]*      //' |
-       sort -u |
-       while IFS= read i
+
+       printf "Merging:\n"
+       printf "%s\n" "$files"
+
+       rc=0
+       for i in $files
        do
                printf "\n"
-               merge_file "$i" < /dev/tty > /dev/tty
-       done
-else
-       while test $# -gt 0; do
-               printf "\n"
-               merge_file "$1"
-               shift
+               if ! merge_file "$i"
+               then
+                       rc=1
+                       prompt_after_failed_merge || exit 1
+               fi
        done
-fi
-exit 0
+
+       exit $rc
+}
+
+main "$@"