Can TortoiseMerge be used as a difftool with Windo

Question

I'm just starting to work with Git. I would like to use TortoiseMerge as the difftool and mergetool.

In my .gtconfig in my personal user directory I have the following sections. I've removed the user and color sections for this question.

[merge]
    tool = tortoisemerge
[mergetool "tortoisemerge"]
    cmd = \"TortoiseMerge.exe\" -base:\"$BASE\" -mine:\"$LOCAL\" -theirs:\"$REMOTE\" -merged:\"$MERGED\"
[diff]
    tool = tortoisemerge
[difftool "tortoisemerge"]
    cmd = \"TortoiseMerge.exe\" -base:\"$BASE\" -mine:\"$LOCAL\" -theirs:\"$REMOTE\" -merged:\"$MERGED\"

If I type tortoisemerge at the Git Bash prompt it loads. It is known to be on the path. But if I type the command I get the following error.

Rich:mygittest (master *)
$ git difftool
error: 'tortoisemerge' can only be used to resolve merges
merge tool candidates: kompare emerge vimdiff
No known merge resolution program available.
external diff died, stopping at readme.txt.
Rich:mygittest (master *)
$ 

What am I not understanding to make this work? Tortoisemerge is installed with TortoiseSVN.

Answer 1

When rebasing, I strongly recommend switch $theirs and $mine, because it is different when you merge and rebase-merge. Check here:

What is the precise meaning of "ours" and "theirs" in git?

So, if you only use mergetool to rebase like me, do:

[mergetool "tortoisemerge"]
cmd = \""c:/Program Files/TortoiseGIT/bin/TortoiseGitMerge.exe"\" -base "$BASE" -theirs "$LOCAL" -mine "$REMOTE" -merged "$MERGED"

Answer 2

Great answer by Klas Mellbourn! Saved me a lotta time. One shortcoming is, newly Added or Removed files in the repository will not show up during the difftool command execution. There's nothing to compare them to! Here's what I did on top of this: (Inspired by my co-worker's answer).

1. Create a file named empty.empty in $Home directory (execute start ~ in your bash). And as the name suggests, keep it empty.
2. Create another file named tortoisediff.sh in $Home/bin directory with following content

:

#!/bin/sh
# $LOCAL $REMOTE seem to be swapped
# $1 is $LOCAL
# $2 is $REMOTE

difftool='/c/Program Files/TortoiseGit/bin/TortoiseGitMerge.exe'
NULL="/dev/null"
empty="C:/home/empty.empty"

if [ "$1" == "$NULL" ]; then
    echo "Added: " "$2"
    "$difftool" /base:"$empty" /mine:"$2" /readonly:"$empty"
elif [ "$2" == "$NULL" ]; then
    echo 'Removed: ' "$1"
    "$difftool" /base:"$1" /readonly:"$1" /mine:"$empty"
else
    echo 'Modified' "$2"
    "$difftool" /base:"$1" /basename:"$1" /readonly:"$1" /mine:"$2" /minename:"$2"
fi

# Checkout https://tortoisegit.org/docs/tortoisegitmerge/tme-automation.html for more

3. Modify your .gitconfig file (Line 11 of the answer)

   cmd = tortoisediff.sh "$LOCAL" "$REMOTE"

This would now make difftool refer to tortoisediff.sh instead of opening the application directly.

4. Keep in mind: you'd have to run git add . followed by git difftool --staged instead of simply git difftool.

Answer 3

The following settings work fine for me. However, I am using TortoiseGit not TortoiseSVN. Notice the difference in the parameters for diff.

[diff]
  tool = tortoisediff
[difftool]
  prompt = false
[merge]
  tool = tortoisemerge
[mergetool]
  prompt = false
  keepBackup = false
[difftool "tortoisediff"]
  cmd = \""c:/Program Files/TortoiseGIT/bin/TortoiseGitMerge.exe"\" -mine "$REMOTE" -base "$LOCAL"
[mergetool "tortoisemerge"]
  cmd = \""c:/Program Files/TortoiseGIT/bin/TortoiseGitMerge.exe"\" -base "$BASE" -theirs "$REMOTE" -mine "$LOCAL" -merged "$MERGED"

Answer 4

[diff]
  tool = tortoisediff
[difftool]
  prompt = false
[merge]
  tool = tortoisemerge
[mergetool]
  prompt = false
  keepBackup = false
[difftool "tortoisediff"]
  cmd = \""C:/Users/$USER/Desktop/TortoiseMerge.exe"\" -base:\"$BASE\" -mine:\"$LOCAL\" -theirs:\"$REMOTE\" -merged:\"$MERGED\"
[mergetool "tortoisemerge"]
  cmd = \""C:/Users/$USER/Desktop/TortoiseMerge.exe"\" -base:\"$BASE\" -mine:\"$LOCAL\" -theirs:\"$REMOTE\" -merged:\"$MERGED\"

This worked for me, using TortoiseMerge 1.6.7 (Portable)

Answer 5

So that filenames with spaces are handled correctly, you should change the last line of @melbourn's answer to

cmd = \""c:/Program Files/TortoiseGIT/bin/TortoiseGitMerge.exe"\" -base "$BASE" -theirs "$REMOTE" -mine "$LOCAL" -merged "$MERGED"