// Track ~/GitRepos/personal to use "personal" ID
~/GitRepos/personal
$ git idm track personal --directory $(pwd)
git config --file /Users/calvin/.gitconfig_idm_personal user.name Calvin Sangbin Park
git config --file /Users/calvin/.gitconfig_idm_personal user.email [email protected]
git config --file /Users/calvin/.gitconfig_idm_personal core.sshCommand ssh -i /Users/calvin/.ssh/id_rsa.github-personal.NVMBP -o IdentitiesOnly=yes -F /dev/null
git config --global includeIf.gitdir:/Users/calvin/GitRepos/personal/.idm personal
git config --global includeIf.gitdir:/Users/calvin/GitRepos/personal/.path /Users/calvin/.gitconfig_idm_personal

// Go to a root of all repos dir
~/GitRepos
$ cd ..

// Check that "work" ID is active
~/GitRepos
$ git idm active
work
    name=Calvin Park
    [email protected]
    sshkey=/Users/calvin/.ssh/id_rsa
    sshcommand=ssh -i /Users/calvin/.ssh/id_rsa -o IdentitiesOnly=yes -F /dev/null
WARNING: /Users/calvin/.ssh/id_rsa has not been added to ssh-agent.  To fix run: ssh-add '/Users/calvin/.ssh/id_rsa'

// Go into ~/GitRepos/personal/book/jenkins-shared-library/ where git idm tracks to use "personal" ID
~/GitRepos
$ cd personal/book/jenkins-shared-library/

// git idm active reports that it's using "work" ID
~/GitRepos/personal/book/jenkins-shared-library
$ git idm active
work
    name=Calvin Park
    [email protected]
    sshkey=/Users/calvin/.ssh/id_rsa
    sshcommand=ssh -i /Users/calvin/.ssh/id_rsa -o IdentitiesOnly=yes -F /dev/null
WARNING: /Users/calvin/.ssh/id_rsa has not been added to ssh-agent.  To fix run: ssh-add '/Users/calvin/.ssh/id_rsa'

// when in reality it's using "personal" ID
~/GitRepos/personal/book/jenkins-shared-library
$ git config user.email
[email protected]

A following git commit showed that "personal" ID is indeed is active, which means git track is working.

I ran into an issue when trying to automate setup for new machines, where .gitconfig is empty. If git-idm track is invoked before git-idm use is invoked for the first time (and user.name and include.path aren't already set), then use will create the sections [user] and [include] after [includeif ...], and those sections will always take precedence and remain active even when in an auto-tracked directory.

It's possible to workaround this by activating an identity first before tracking any directories, but the behavior surprised and confused me.

To reproduce

# create a dummy repository
mkdir -p ~/Work/bizcorp-repo
git init ~/Work/bizcorp-repo

# configure git identities
git-idm add personal --name "JaNe DoPe" --email "[email protected]" --ssh-command "..."
git-idm add work     --name "Jane Doe"  --email "[email protected]"   --ssh-command "..."
git-idm track work   --directory ~/Work
git-idm use personal

# check that it worked
cd ~/Work/bizcorp-repo
git config user.name # -> JaNe DoPe

# oh no, it didn't! how unprofessional.

Explanation

The commands above create ~/.gitconfig like this:

[gitidm "personal"]
	name = JaNe DoPe
	email = [email protected]
	sshCommand = ...
[gitidm "work"]
	name = Jane Doe
	email = [email protected]
	sshCommand = ...
[includeIf "gitdir:~/Work"]
	idm = work
	path = ~/.gitconfig_idm_work
[user]
	name = JaNe DoPe
	email = [email protected]
	activeidm = personal
[include]
	path = ~/.gitconfig_idm_personal

Because the [user] and [include] sections exist below [includeIf], they end up overwriting the tracking configs.

Solution

I don't think git-config has any commands for re-ordering sections, so I think invoking git-idm track should check first if an active identity is set (i.e. if key user.name and include.path already exist), and if not, try to activate one of them in order to populate those sections with dummy values prior to the creation of include rules which should overwrite them.

Kind of rusty with Bash scripting right now, but I might try to implement the fix myself.

https://dev.to/maxlmator/maintaining-different-git-identities

It would be nice for identities to auto-select based on a local directory (optionally given).

[includeIf "gitdir:~/git/github/"]
    path = /home/sam/.gitconfig_idm_github

And the contents of /home/sam/.gitconfig_idm_github would be...

[user]
    name = Sam Gleske
    email = [email protected]
[core]
    sshCommand = ssh -i /home/sam/.ssh/id_rsa -o IdentitiesOnly=yes -F /dev/null

Assuming that the git idm identity is...

[user]
    name = Sam Gleske
    email = [email protected]
    activeidm = github
[gitidm "github"]
    name = Sam Gleske
    email = [email protected]
    sshKey = /home/sam/.ssh/id_rsa
    sshCommand = ssh -i /home/sam/.ssh/id_rsa -o IdentitiesOnly=yes -F /dev/null

This will require a minimum version of git 2.13.0 for this.

Brainstorming feature

I think it makes sense to add this as a sub-command git idm directory which associates the identity name with the directory.

# personal projects
git idm directory add github ~/git/github/

# work projects
git idm directory add work ~/git/work/

# generically
git idm directory [add|remove] [git idm identity] [project path to apply identity]

We could tie the identity with an idm subkey in .gitconfig like:

[includeIf "gitdir:~/git/github/"]
    idm = github
    path = /home/sam/.gitconfig_idm_github

When removing an identity we'll want it to search for all includeIf settings where idm key is equal to the identity being removed. We'll also want to delete the file.

Using the prefix .gitconfig_idm_[git idm identity] for the file seems like the best way to avoid clashing with potential user configuration files.