# git credential helpers

# General remarks

- For `git credential approve` git (2.28.0 macOS) does not even call the credential helper if no username is supplied:

      ❯ export GIT_TRACE=true
      ❯ (echo url=https://github.com; echo password=secret; echo ) | git credential approve
      10:43:36.712290 git.c:444               trace: built-in: git credential approve
      ❯

- The `credential.helper` key has a multi-set value, so if you add a new value, the old values are still kept. From git 2.9 specifying an empty string removes the previously defined helpers.

# Credential helper survey

We do this with an eye of supporting usernames and multiple users.

## `cache`

- Docs: https://git-scm.com/docs/git-credential-cache

- This helper is not included in the default git installer on Windows . :(

- This is how we can set up `cache` for a particular repository:

      ❯ mkdir foo
      ❯ cd foo
      ❯ git init .
      11:43:28.618841 git.c:444               trace: built-in: git init .
      Initialized empty Git repository in /private/tmp/foo/.git/

      ❯ git config --add credential.helper ""
      11:43:50.682962 git.c:444               trace: built-in: git config --add credential.helper ''

      ❯ git config --add credential.helper cache
      11:43:54.577707 git.c:444               trace: built-in: git config --add credential.helper cache

      ❯ cat .git/config
      [core]
          repositoryformatversion = 0
          filemode = true
          bare = false
          logallrefupdates = true
          ignorecase = true
          precomposeunicode = true
      [credential]
          helper =
          helper = cache

- Now let’s add credentials:

      ❯  (echo url=https://github.com; echo username=token; echo password=secret; echo ) | git credential approve
      11:45:16.813913 git.c:444               trace: built-in: git credential approve
      11:45:16.814431 run-command.c:663       trace: run_command: 'git credential-cache store'
      11:45:16.823008 git.c:704               trace: exec: git-credential-cache store
      11:45:16.823637 run-command.c:663       trace: run_command: git-credential-cache store
      11:45:16.842902 run-command.c:663       trace: run_command: git-credential-cache--daemon /Users/gaborcsardi/.cache/git/credential/socket

      ❯  (echo url=https://github.com; echo username=token2; echo password=secret2; echo ) | git credential approve
      11:45:28.927712 git.c:444               trace: built-in: git credential approve
      11:45:28.928108 run-command.c:663       trace: run_command: 'git credential-cache store'
      11:45:28.937087 git.c:704               trace: exec: git-credential-cache store
      11:45:28.937695 run-command.c:663       trace: run_command: git-credential-cache store

- Query with username works correctly:

      ❯ (echo url=https://token@github.com; echo ) | git credential fill
      11:46:40.689122 git.c:444               trace: built-in: git credential fill
      11:46:40.689638 run-command.c:663       trace: run_command: 'git credential-cache get'
      11:46:40.696784 git.c:704               trace: exec: git-credential-cache get
      11:46:40.697333 run-command.c:663       trace: run_command: git-credential-cache get
      protocol=https
      host=github.com
      username=token
      password=secret

      ❯ (echo url=https://token2@github.com; echo ) | git credential fill
      11:46:43.767002 git.c:444               trace: built-in: git credential fill
      11:46:43.767676 run-command.c:663       trace: run_command: 'git credential-cache get'
      11:46:43.778637 git.c:704               trace: exec: git-credential-cache get
      11:46:43.779201 run-command.c:663       trace: run_command: git-credential-cache get
      protocol=https
      host=github.com
      username=token2
      password=secret2

- Query without username works, and returns some credential:

      ❯ (echo url=https://github.com; echo ) | git credential fill
      11:45:58.200272 git.c:444               trace: built-in: git credential fill
      11:45:58.200667 run-command.c:663       trace: run_command: 'git credential-cache get'
      11:45:58.208372 git.c:704               trace: exec: git-credential-cache get
      11:45:58.208919 run-command.c:663       trace: run_command: git-credential-cache get
      protocol=https
      host=github.com
      username=token
      password=secret

      ❯ (echo url=https://token@github.com; echo ) | git credential reject
      11:47:03.921697 git.c:444               trace: built-in: git credential reject
      11:47:03.922530 run-command.c:663       trace: run_command: 'git credential-cache erase'
      11:47:03.935858 git.c:704               trace: exec: git-credential-cache erase
      11:47:03.936400 run-command.c:663       trace: run_command: git-credential-cache erase

      ❯ (echo url=https://github.com; echo ) | git credential fill
      11:47:10.018877 git.c:444               trace: built-in: git credential fill
      11:47:10.019386 run-command.c:663       trace: run_command: 'git credential-cache get'
      11:47:10.027990 git.c:704               trace: exec: git-credential-cache get
      11:47:10.028572 run-command.c:663       trace: run_command: git-credential-cache get
      protocol=https
      host=github.com
      username=token2
      password=secret2

## `store`

- Docs: https://git-scm.com/docs/git-credential-store

- Configure for a repo:

      ❯ mkdir foo
      ❯ cd foo
      ❯ git init .
      11:53:48.042569 git.c:444               trace: built-in: git init .
      Initialized empty Git repository in /private/tmp/foo/.git/

      ❯ git config --add credential.helper ""
      11:53:52.949914 git.c:444               trace: built-in: git config --add credential.helper ''

      ❯ git config --add credential.helper store
      11:53:56.682348 git.c:444               trace: built-in: git config --add credential.helper store

      ❯ cat .git/config
      [core]
          repositoryformatversion = 0
          filemode = true
          bare = false
          logallrefupdates = true
          ignorecase = true
          precomposeunicode = true
      [credential]
          helper =
          helper = store

- Add credentials:

      ❯  (echo url=https://github.com; echo username=token; echo password=secret; echo ) | git credential approve
      11:54:44.184929 git.c:444               trace: built-in: git credential approve
      11:54:44.185729 run-command.c:663       trace: run_command: 'git credential-store store'
      11:54:44.197920 git.c:704               trace: exec: git-credential-store store
      11:54:44.198471 run-command.c:663       trace: run_command: git-credential-store store

      /tmp/foo master
      ❯  (echo url=https://github.com; echo username=token2; echo password=secret2; echo ) | git credential approve
      11:54:48.452942 git.c:444               trace: built-in: git credential approve
      11:54:48.453399 run-command.c:663       trace: run_command: 'git credential-store store'
      11:54:48.463535 git.c:704               trace: exec: git-credential-store store
      11:54:48.464004 run-command.c:663       trace: run_command: git-credential-store store

- Query with username:

      ❯ (echo url=https://token@github.com; echo ) | git credential fill
      11:55:21.191654 git.c:444               trace: built-in: git credential fill
      11:55:21.192357 run-command.c:663       trace: run_command: 'git credential-store get'
      11:55:21.204279 git.c:704               trace: exec: git-credential-store get
      11:55:21.205063 run-command.c:663       trace: run_command: git-credential-store get
      protocol=https
      host=github.com
      username=token
      password=secret

      ❯ (echo url=https://token2@github.com; echo ) | git credential fill
      11:55:24.194096 git.c:444               trace: built-in: git credential fill
      11:55:24.194654 run-command.c:663       trace: run_command: 'git credential-store get'
      11:55:24.207028 git.c:704               trace: exec: git-credential-store get
      11:55:24.207643 run-command.c:663       trace: run_command: git-credential-store get
      protocol=https
      host=github.com
      username=token2
      password=secret2

- Query without username returns some credentials, apparently not the ones that were set first:

      ❯ (echo url=https://github.com; echo ) | git credential fill
      11:56:12.394594 git.c:444               trace: built-in: git credential fill
      11:56:12.394949 run-command.c:663       trace: run_command: 'git credential-store get'
      11:56:12.403303 git.c:704               trace: exec: git-credential-store get
      11:56:12.403863 run-command.c:663       trace: run_command: git-credential-store get
      protocol=https
      host=github.com
      username=token2
      password=secret2

      ❯ (echo url=https://token2@github.com; echo ) | git credential reject
      11:56:24.065910 git.c:444               trace: built-in: git credential reject
      11:56:24.066314 run-command.c:663       trace: run_command: 'git credential-store erase'
      11:56:24.074851 git.c:704               trace: exec: git-credential-store erase
      11:56:24.076875 run-command.c:663       trace: run_command: git-credential-store erase

      ❯ (echo url=https://github.com; echo ) | git credential fill
      11:56:26.438444 git.c:444               trace: built-in: git credential fill
      11:56:26.438839 run-command.c:663       trace: run_command: 'git credential-store get'
      11:56:26.446181 git.c:704               trace: exec: git-credential-store get
      11:56:26.446721 run-command.c:663       trace: run_command: git-credential-store get
      protocol=https
      host=github.com
      username=token
      password=secret

## `osxkeychain`

- Some docs: https://docs.github.com/en/github/using-git/updating-credentials-from-the-osx-keychain

- This is the default helper on macOS currently (git 2.28.0).

- This is how it stores a credential:

      Name: github.com
      Kind: Internet password
      Account: token
      Where: https://github.com

- It installs as a git subcommand, so it is possible to call its internal api directly:

      ❯ git credential-osxkeychain
      11:50:56.325499 git.c:704               trace: exec: git-credential-osxkeychain
      11:50:56.325783 run-command.c:663       trace: run_command: git-credential-osxkeychain
      usage: git credential-osxkeychain <get|store|erase>

- As always, needs `username` when setting the credential.

- No need to supply `username` to get some token that matches the host. This is in a clean keychain. First we set two credentials:

      ❯ (echo url=https://github.com; echo username=token; echo password=secret; echo ) | git credential approve
      10:48:47.187164 git.c:444               trace: built-in: git credential approve
      10:48:47.187691 run-command.c:663       trace: run_command: 'git credential-osxkeychain store'
      10:48:47.197964 git.c:704               trace: exec: git-credential-osxkeychain store
      10:48:47.198518 run-command.c:663       trace: run_command: git-credential-osxkeychain store

      ❯ (echo url=https://github.com; echo username=token2; echo password=secret2; echo ) | git credential approve
      10:48:55.299933 git.c:444               trace: built-in: git credential approve
      10:48:55.300282 run-command.c:663       trace: run_command: 'git credential-osxkeychain store'
      10:48:55.308568 git.c:704               trace: exec: git-credential-osxkeychain store
      10:48:55.309276 run-command.c:663       trace: run_command: git-credential-osxkeychain store

  If we don’t supply a username, then we’ll just get one of them:

      ❯ (echo url=https://github.com; echo ) | git credential fill
      10:49:17.371636 git.c:444               trace: built-in: git credential fill
      10:49:17.372021 run-command.c:663       trace: run_command: 'git credential-osxkeychain get'
      10:49:17.378688 git.c:704               trace: exec: git-credential-osxkeychain get
      10:49:17.379164 run-command.c:663       trace: run_command: git-credential-osxkeychain get
      protocol=https
      host=github.com
      username=token
      password=secret

  If we supply the username, then we’ll get the correct one:

      ❯ (echo url=https://token2@github.com; echo ) | git credential fill
      10:49:28.613779 git.c:444               trace: built-in: git credential fill
      10:49:28.614108 run-command.c:663       trace: run_command: 'git credential-osxkeychain get'
      10:49:28.621440 git.c:704               trace: exec: git-credential-osxkeychain get
      10:49:28.621979 run-command.c:663       trace: run_command: git-credential-osxkeychain get
      protocol=https
      host=github.com
      username=token2
      password=secret2

  To check that without a username we get an arbitrary one, let’s remove `token`:

      ❯ (echo url=https://token@github.com; echo ) | git credential reject
      10:49:58.584332 git.c:444               trace: built-in: git credential reject
      10:49:58.586880 run-command.c:663       trace: run_command: 'git credential-osxkeychain erase'
      10:49:58.598463 git.c:704               trace: exec: git-credential-osxkeychain erase
      10:49:58.599214 run-command.c:663       trace: run_command: git-credential-osxkeychain erase

      ```sh
      ❯ (echo url=https://github.com; echo ) | git credential fill
      10:50:07.468385 git.c:444               trace: built-in: git credential fill
      10:50:07.468728 run-command.c:663       trace: run_command: 'git credential-osxkeychain get'
      10:50:07.478398 git.c:704               trace: exec: git-credential-osxkeychain get
      10:50:07.478832 run-command.c:663       trace: run_command: git-credential-osxkeychain get
      protocol=https
      host=github.com
      username=token2
      password=secret2

  Now let’s re-add token to make sure that `osxkeychain` does not prefer `token`:

      ❯ (echo url=https://github.com; echo username=token; echo password=secret; echo ) | git credential approve
      10:58:52.302066 git.c:444               trace: built-in: git credential approve
      10:58:52.311063 run-command.c:663       trace: run_command: 'git credential-osxkeychain store'
      10:58:52.321633 git.c:704               trace: exec: git-credential-osxkeychain store
      10:58:52.322108 run-command.c:663       trace: run_command: git-credential-osxkeychain store

      ❯ (echo url=https://github.com; echo ) | git credential fill
      10:58:57.316418 git.c:444               trace: built-in: git credential fill
      10:58:57.317630 run-command.c:663       trace: run_command: 'git credential-osxkeychain get'
      10:58:57.330142 git.c:704               trace: exec: git-credential-osxkeychain get
      10:58:57.330697 run-command.c:663       trace: run_command: git-credential-osxkeychain get
      protocol=https
      host=github.com
      username=token2
      password=secret2

  So it seems that `osxkeychain` will just find an arbitrary one, or the one that was added first.

## `manager-core` (on macOS), before version 2.0.246-beta

- Not installed by default (git 2.28.0).

- Install from brew, according to the instructions: https://github.com/microsoft/Git-Credential-Manager-Core#macos-homebrew

- If updates your global git config, adding these lines:

      [credential]
          helper = ""
      [credential "https://dev.azure.com"]
          useHttpPath = true
      [credential]
          helper = manager-core

  The `helper = ""` line deletes previous handlers. The system helper is kept as `osxkeychain`.

- It installs as a git subcommand, and you can call its internal API directly:

      ❯ git credential-manager-core
      11:51:56.434300 git.c:704               trace: exec: git-credential-manager-core
      11:51:56.434496 run-command.c:663       trace: run_command: git-credential-manager-core
      Missing command.

      usage: git-credential-manager-core <command>

        Available commands:
          erase
          get
          store

          configure [--system]
          unconfigure [--system]

          --version, version
          --help, -h, -?

- It is not compatible with the `osxkeychain` helper, because it uses different keys in the keychain.

- It supports different providers. Providers are auto-detected by default. GitHub has its own provider, detected via the `github.com` URL. The provider can be configured user a git config key or an environment variable: https://github.com/microsoft/Git-Credential-Manager-Core/blob/master/docs/configuration.md#credentialprovider

- It does not currently supports namepaces (like `manager`).

- This is how it stores a credential:

      Name: git:https://github.com
      Kind: application password
      Account: token
      Where: git:https://github.com

- No need to supply `username` to get some credential:

      ❯ (echo url=https://github.com; echo ) | git credential fill
      11:24:47.750966 git.c:444               trace: built-in: git credential fill
      11:24:47.753268 run-command.c:663       trace: run_command: 'git credential-manager-core get'
      11:24:47.762249 git.c:704               trace: exec: git-credential-manager-core get
      11:24:47.762917 run-command.c:663       trace: run_command: git-credential-manager-core get
      protocol=https
      host=github.com
      username=token
      password=secret

- If there are multiple credentials, a random one (or the one set first?) is returned:

      ❯  (echo url=https://github.com; echo username=token2; echo password=secret2; echo ) | git credential approve
      11:25:41.553761 git.c:444               trace: built-in: git credential approve
      11:25:41.554242 run-command.c:663       trace: run_command: 'git credential-manager-core store'
      11:25:41.565748 git.c:704               trace: exec: git-credential-manager-core store
      11:25:41.566218 run-command.c:663       trace: run_command: git-credential-manager-core store

- In fact the username is completely ignored when getting credentials, at least for the GitHub provider:

      ❯ (echo url=https://token2@github.com; echo ) | git credential fill
      11:29:49.274574 git.c:444               trace: built-in: git credential fill
      11:29:49.275020 run-command.c:663       trace: run_command: 'git credential-manager-core get'
      11:29:49.283563 git.c:704               trace: exec: git-credential-manager-core get
      11:29:49.284236 run-command.c:663       trace: run_command: git-credential-manager-core get
      protocol=https
      host=github.com
      username=token
      password=secret

  This is because the username is not stored as part of the URL by the GitHub provider. Related issue: https://github.com/microsoft/Git-Credential-Manager-Core/issues/160 `manager` has a similar problem, it is linked from this GitHub issue.

- If you set the provider to Generic, then usernames work as expected. In this case, this is stored in the keychain:

      Name: git:https://token@github.com/
      Kind: application password
      Account: token
      Where: git:https://token@github.com/

  These credentials are not compatible with the ones set by the GitHub provider.

      ❯ export GCM_PROVIDER=generic

      ❯  (echo url=https://github.com; echo username=token; echo password=secret; echo ) | git credential approve
      11:34:15.998644 git.c:444               trace: built-in: git credential approve
      11:34:15.998992 run-command.c:663       trace: run_command: 'git credential-manager-core store'
      11:34:16.008178 git.c:704               trace: exec: git-credential-manager-core store
      11:34:16.008834 run-command.c:663       trace: run_command: git-credential-manager-core store

      ❯  (echo url=https://github.com; echo username=token2; echo password=secret2; echo ) | git credential approve
      11:35:52.629963 git.c:444               trace: built-in: git credential approve
      11:35:52.637966 run-command.c:663       trace: run_command: 'git credential-manager-core store'
      11:35:52.648058 git.c:704               trace: exec: git-credential-manager-core store
      11:35:52.648514 run-command.c:663       trace: run_command: git-credential-manager-core store

      ❯ (echo url=https://token@github.com; echo ) | git credential fill
      11:35:58.336428 git.c:444               trace: built-in: git credential fill
      11:35:58.336881 run-command.c:663       trace: run_command: 'git credential-manager-core get'
      11:35:58.345187 git.c:704               trace: exec: git-credential-manager-core get
      11:35:58.345729 run-command.c:663       trace: run_command: git-credential-manager-core get
      protocol=https
      host=github.com
      username=token
      password=secret

      ❯ (echo url=https://token2@github.com; echo ) | git credential fill
      11:36:02.550339 git.c:444               trace: built-in: git credential fill
      11:36:02.550695 run-command.c:663       trace: run_command: 'git credential-manager-core get'
      11:36:02.557777 git.c:704               trace: exec: git-credential-manager-core get
      11:36:02.558359 run-command.c:663       trace: run_command: git-credential-manager-core get
      protocol=https
      host=github.com
      username=token2
      password=secret2

## `manager-core` (macOS), 2.0.246-beta or later

- This version adds better support for multiple credentials for the same host.
- It does not save the `username` as part of the service any more, for the generic provider.
- It does save the `username` as `account` and it uses it when searching for credentials, both for the `generic` and the `github` provider.

## `manager` (GitHub authority)

- This was Git Credential Manager for Windows, and it is the default helper on Windows for git 2.28.0. In git 2.29.0 it is not the default any more, and it is deprecated in favor of `manager-core`. It is still installed, though.

- Docs: https://github.com/Microsoft/Git-Credential-Manager-for-Windows

- It is installed as a git subcommand, so it can be called directly:

      ❯ $env:GIT_TRACE="true"
      ❯ git credential-manager
      12:15:45.554298 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      12:15:45.556249 git.c:704               trace: exec: git-credential-manager
      12:15:45.556249 run-command.c:663       trace: run_command: git-credential-manager
      usage: git-credential-manager.exe [approve|clear|config|delete|deploy|erase|fill|get|install|reject|remove|store|uninstall|version] [<args>]
      fatal: Unable to open help documentation.

- Setting credentials. The `username` must be provided, and it is stored in the credential, but the GitHub provider overwrites credentials with the same host name, even if they have a different `username`. I.e. after this, there will be only one credential:

      ❯  %  { echo url=https://github.com; echo username=token; echo password=secret; echo "" } | git credential approve
      13:16:58.118611 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:16:58.120617 git.c:444               trace: built-in: git credential approve
      13:16:58.122612 run-command.c:663       trace: run_command: 'git credential-manager store'
      13:16:58.170625 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:16:58.173087 git.c:704               trace: exec: git-credential-manager store
      13:16:58.173087 run-command.c:663       trace: run_command: git-credential-manager store

      ❯  %  { echo url=https://github.com; echo username=token2; echo password=secret2; echo "" } | git credential approve
      13:17:30.925970 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:17:30.928134 git.c:444               trace: built-in: git credential approve
      13:17:30.928987 run-command.c:663       trace: run_command: 'git credential-manager store'
      13:17:30.968981 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:17:30.970974 git.c:704               trace: exec: git-credential-manager store
      13:17:30.970974 run-command.c:663       trace: run_command: git-credential-manager store

- It stores credentials in the following format:

      Internet or network address: git:https://github.com
      User name: token
      Password: ****
      Persistence: Local computer

<!- - –>

- It has multiple authorities, (like providers for `manager-core`). The GitHub authority is used for `github.com` URLs by default. The authority can be set with a config option or an env var.

- We need to set the `GCM_VALIDATE` env var to `false` , otherwise it tries to validate the GitHub token every time we query it.

      ❯ $env:GCM_VALIDATE="false"

- No `username` is needed for getting the credential, for the GitHub provider.

      ❯  %  { echo url=https://github.com; echo "" } | git credential fill
      13:24:43.831089 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:24:43.833666 git.c:444               trace: built-in: git credential fill
      13:24:43.834092 run-command.c:663       trace: run_command: 'git credential-manager get'
      13:24:43.872087 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:24:43.874092 git.c:704               trace: exec: git-credential-manager get
      13:24:43.874092 run-command.c:663       trace: run_command: git-credential-manager get
      protocol=https
      host=github.com
      path=
      username=token2
      password=secret2

  In fact the `username` is ignored for the GitHub provider:

      ❯ %  { echo url=https://token@github.com; echo "" } | git credential fill
      13:25:06.029084 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:25:06.031084 git.c:444               trace: built-in: git credential fill
      13:25:06.032081 run-command.c:663       trace: run_command: 'git credential-manager get'
      13:25:06.069085 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:25:06.070086 git.c:704               trace: exec: git-credential-manager get
      13:25:06.070086 run-command.c:663       trace: run_command: git-credential-manager get
      protocol=https
      host=github.com
      path=
      username=token2
      password=secret2

- Supports namespaces, the default namespace is `git`. The namespace is included in the name of the credential: `namespace:URL`.

- There is a pull request to include the `username` in the URL as well: https://github.com/microsoft/Git-Credential-Manager-for-Windows/pull/891

## `manager` (Basic authority)

- `Basic` authority can be configured with an env var or config option:

      ❯ $env:GCM_AUTHORITY="Basic"

- It is compatible with the credentials set by the `GitHub` authority:

      ❯  %  { echo url=https://github.com; echo "" } | git credential fill
      13:27:17.344396 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:27:17.346397 git.c:444               trace: built-in: git credential fill
      13:27:17.347388 run-command.c:663       trace: run_command: 'git credential-manager get'
      13:27:17.386388 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:27:17.388386 git.c:704               trace: exec: git-credential-manager get
      13:27:17.388386 run-command.c:663       trace: run_command: git-credential-manager get
      protocol=https
      host=github.com
      path=
      username=token2
      password=secret2

- But it supports usernames as well. Note that since the username is stored in the URL, it does not return some arbitrary credentials if we query the URL without a username. We need to tell GCM here not to ask for a password, but just fall back to the next credential helper.

      ❯ $env:GCM_INTERACTIVE="Never"

      ❯ % { echo url=https://token2@github.com; echo "" } | git -c credential.helper="! echo protocol=dummy; echo host=dummy;
       echo username=dummy; echo password=dummy" credential fill
      13:31:16.682545 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:31:16.684473 git.c:444               trace: built-in: git credential fill
      13:31:16.685471 run-command.c:663       trace: run_command: 'git credential-manager get'
      13:31:16.725486 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:31:16.727472 git.c:704               trace: exec: git-credential-manager get
      13:31:16.727472 run-command.c:663       trace: run_command: git-credential-manager get
      Logon failed, use ctrl+c to cancel basic credential prompt.
      13:31:16.948468 run-command.c:663       trace: run_command: ' echo protocol=dummy; echo host=dummy; echo username=dummy; echo password=dummy get'
      protocol=dummy
      host=dummy
      username=dummy
      password=dummy get

- When setting credentials, usernames are included in the URL:

      ❯ % { echo url=https://github.com; echo username=token; echo password=secret; echo "" } | git credential approve
      13:34:37.937934 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:34:37.940820 git.c:444               trace: built-in: git credential approve
      13:34:37.940995 run-command.c:663       trace: run_command: 'git credential-manager store'
      13:34:37.983372 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:34:37.984737 git.c:704               trace: exec: git-credential-manager store
      13:34:37.984737 run-command.c:663       trace: run_command: git-credential-manager store

  will create this record in the credential store:

      Internet or network address: git:https://token@github.com
      User name: token
      Password: ****
      Persistence: Local computer

  and then this can be queried with an explicit username:

      ❯  %  { echo url=https://token@github.com; echo "" } | git -c credential.helper="! echo protocol=dummy; echo host=dummy; echo username=dummy; echo password=dummy" credential fill
      13:36:42.789268 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/bin
      13:36:42.791270 git.c:444               trace: built-in: git credential fill
      13:36:42.792266 run-command.c:663       trace: run_command: 'git credential-manager get'
      13:36:42.830475 exec-cmd.c:237          trace: resolved executable dir: C:/Program Files/Git/mingw64/libexec/git-core
      13:36:42.832279 git.c:704               trace: exec: git-credential-manager get
      13:36:42.832279 run-command.c:663       trace: run_command: git-credential-manager get
      protocol=https
      host=github.com
      path=
      username=token
      password=secret

## `manager-core` (on Windows, before version 2.0.246-beta)

- Not installed by default (git 2.28.0), but this is supposed to be the future canonical implementation. See above for the macOS version.

- It works similarly to `manager` , I haven’t seen any differences in behavior (version was 2.0.194.40577). Instead of authorities, we need to set up providers: https://github.com/microsoft/Git-Credential-Manager-Core/blob/master/docs/migration.md#gcm_authority. The `Generic` provider works the same way as the `Basic` authority in `manager`.

- Unfortunately setting `GCM_AUTHORITY` will make `manager-core` break, so it is not possible to use both `manager` and `manager-core` if you need to set this environment variable.

## `manager-core` (on Windows, from 2.0.246-beta)

- This is now the version that is the default helper in git 2.29.0 and later. `manager` is still installed, but the default system config sets `manager-core`.
- It supports multiple users better: https://github.com/microsoft/Git-Credential-Manager-Core/issues/160#issuecomment-700544889
- When storing a credential, it first checks if there is a target name without a username. If there is, then it uses the target name without the username. It stores the username in the `username` field of the credential, still. so it is not lost.
- When looking up a credential without a username, it will return the first credential it can find, even if the target name contains a username, and there is another credential without a username in the target name.
- When looking up a credential with a username, it may return any credential with a matching username, and a target name that matches the host. The username inside the target name does not actually matter.

# Recommendations for multiple accounts

## macOS

1. Use the `osxkeychain` helper.

2. FIrst remove all your current credentials for the host you are targeting. E.g. for GitHub, search for “Internet Passwords” for github.com, or use `gitcreds::gitcreds_list()` and the oskeyring package to remove them. You can also use the oskeyring package to back up the tokens and passwords.

3. Then add the credential that you want to use for “generic access”. This is the credential that will be used for URLs without user names. The user name for this credential does not matter, but you can choose something descriptive, e.g. “PersonalAccessToken”, “token”, or “generic”.

4. Configure git to use this username by default. E.g. if you chose “generic”, then run

       git config --global crendetial.username generic

5. Add all the other credentials, with appropriate user names. These are the user names that you need to put in the URLs for the repositories or operations you want to use them for. (GitHub does not actually use the user names if the password is a PAT.)

## Windows, with git 2.29.0 or later and manager-core

1. We suggest that you update to the latest git version, but at least 2.29.0, and use the `manager-core` helper which is now default. If you installed `manager-core` separately from git, we suggest that you remove it, because it might cause confusion as to which helper is actually used.

2. Remove all current credentials first, for the host you are targeting. You can do this in ‘Credential Manager’ or `gitcreds::gitcreds_list()` to find them and the oskeyring package to remove them. You can also use the oskeyring packaeg to back up the tokens and passwords.

3. Then add the credential that you want to use for “generic access”. This is the credential that will be used for URLs without user names. The user name for this credential does not matter, but you can choose something descriptive, e.g. “PersonalAccessToken”, “token”, or “generic”.

4. Configure git to use this username by default. E.g. if you chose “generic”, then run

   git config –global crendetial.username generic

5. Add all the other credentials, with appropriate user names. These are the user names that you need to put in the URLs for the repositories or operations you want to use them for. (GitHub does not actually use the user names if the password is a PAT.)

## Windows with older git versions

### At most one github.com credential

If you only need to manage a single github.com credential, together with possibly multiple credentials to other hosts (including GitHub Enterprise hosts), then you can use the default `manager` helper, and get away with the default auto-detected GCM authority setting.

In this case, you can add you github.com credential with an arbitrary user name, and for each other host you can add configure a default user name, and/or include user names in the URLs to these hosts. This is how to set a default user name for a host:

    git config --global credential.https://example.com.username myusername

### Multiple GitHub credentials

If you need to manage multiple github.com credentials, then you can still use the `manager` helper, but you need to change the GCM authority by setting an option or an environment variable, see https://github.com/microsoft/Git-Credential-Manager-for-Windows/blob/master/Docs/Configuration.md#authority. Once https://github.com/microsoft/Git-Credential-Manager-for-Windows/pull/891 is merged, you won’t need to do this. (At least in recent git versions, that contain a GCM build with the fix.)

This is how to change the config for this:

    git config --global credential.authority Basic

You can also change it only for github.com:

    git config --global credential.github.com.authority Basic

Then you can configure a default user name, this will be used for URLs without a user name:

    git config --global credential.username generic

Now you can add you credentials, the default one with the “generic” user name, and all the others with their specific user and host names.