Support for git-mergetool about fac

[hkdobrev]

@auscompgeek I haven't. Forgot about that! Thanks for the tip!

OK, so this works:

git config --global mergetool.fac.cmd fac
git config --global merge.tool fac

Now git-mergetool starts fac. However, it's started with all files and when you close it, Git opens it for the next file. So it's not suitable in this mode. I think it should detect it's used as a mergetool based on the command line arguments passed to it and open only the specified file so this workflow works.

[mkchoi212]

I have no idea. I will look into it though! Thanks for the heads up!

[auscompgeek]

@hkdobrev Did you set mergetool.fac.cmd, as per git-config(1)?

[mkchoi212]

Tried fmt.Println(len(os.Args), os.Args) but seems like nothing special is passed to the program by git. Any ideas on how we could detect if git-mergetool started fac?

Only one that comes to my mind is running ps || pgrep to find if git-mergetool is running.

[auscompgeek]

A number of environment variables are set by git-mergetool(1). You could take a look at how the known mergetools to git are implemented by looking at the shell scripts in /usr/lib/git-core/mergetools/.

You can pass any argument you like in the cmd setting, so there's definitely no need for pgrep hacks.

[hkdobrev]

From git help config:

mergetool.<tool>.cmd
Specify the command to invoke the specified merge tool. The specified command is evaluated in shell with the following variables available:
BASE is the name of a temporary file containing the common base of the files to be merged, if available;
LOCAL is the name of a temporary file containing the contents of the file on the current branch;
REMOTE is the name of a temporary file containing the contents of the file from the branch being merged;
MERGED contains the name of the file to which the merge tool should write the results of a successful merge.

So the configuration in .gitconfig should be something like:

[mergetool.fac]
    cmd = fac $BASE $LOCAL $REMOTE

An example from the opendiff mergetool opening FileMerge from XCode:

"$merge_tool_path" "$LOCAL" "$REMOTE" -ancestor "$BASE" -merge "$MERGED" | cat

I guess you can either specify arguments or command line options for these and include a simple shell file in the repo to run it. This way it would be a 2-line configuration to use fac as your mergetool :)