Change git idm automatically based on project directory location

[samrocketman]

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 = me@example.com
[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 = me@example.com
    activeidm = github
[gitidm "github"]
    name = Sam Gleske
    email = me@example.com
    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.

[samrocketman]

This feature has been implemented in 0.7 release. I changed around the option names based on limitations in current program design. I tried making sense of the option naming as much as possible. I don't think the result is that bad and is helpful for configuring an advanced git feature easily.

Let's say you have a work identity and a personal identity.

git idm track work --directory ~/git/work
git idm track work --directory ~/git/work2
git idm track personal --directory ~/git/github

List directories associated with a given identity. The directories will auto-switch to the identity for git commit authorship and private key for pushing over SSH.

git idm list work --tracked

Removing identities and running git idm uninstall will have expected cleanup behavior.