gh-difftool

A difftool extension to the GitHub CLI, gh.

Launches a difftool to show the differences of a pull request. The files will be created in a temporary directory with the base branch version of the files prefixed with base_.

Usage: gh-difftool [OPTIONS] [PR] [-- <FILES>...]

Arguments:
  [PR]
          The pull request to diff
          
          When omitted the pull request associated with the current branch will be used
          A pull request can be supplied as argument in any of the following formats:
          - by number, e.g. "123"
          - by URL, e.g. "https://github.com/OWNER/REPO/pull/123"

  [FILES]...
          Specific files to diff.
          
          When not provided all of the files that changed in the pull request will be diffed

Options:
  -t, --tool <TOOL>
          The tool to use for diffing
          
          [env: GH_DIFFTOOL=]

  -R, --repo <OWNER/REPO>
          The GitHub repo to diff, defaults to the GitHub remote of the current git repo

      --name-only
          Show only the names of files that changed in a pull request

      --rotate-to <ROTATE_TO>
          Start showing the diff for the given file, the files before it will move to end.
          
          Applied before `--skip-to`. This behavior deviates from `git-difftool` which
          seems to ignore rotation when `--skip-to` is present.

      --skip-to <SKIP_TO>
          Start showing the diff for the given file, skipping all the files before it

  -h, --help
          Print help information (use `-h` for a summary)

  -V, --version
          Print version information

With no args, the tool will try to diff the current branch's pull request.

When provided a pull request number or URL will diff that pull request. When provided a repo (requires a pull request number), will diff that repo's pull request.

For instance one can do the following from any cloned GitHub repo

gh difftool --repo speedyleion/gh-difftool 10

Installation

This can be installed like any other GitHub CLI extension, https://docs.github.com/en/github-cli/github-cli/using-github-cli-extensions

gh extension install speedyleion/gh-difftool

Current installs support:

• x86_64 Linux
• arm64 Android
• x86_64 Mac
• arm64 Mac
• x86_64 Windows

Configuration

By default, the tool to use will be derived from the current git configuration https://git-scm.com/docs/git-difftool. The diff.tool git configuration option will be used to determine the tool. Similar to git, if diff.tool is not set then merge.tool will be used. Unlike git, if neither option is set gh-difftool will report an error.

Alternatively one can specify a tool to use via the command line argument -t, --tool or by the environment variable GH_DIFFTOOL.

There are a handful of known difftools available in gh-difftool, (bc, bc3, bc4, meld, gvimdiff). These known tools assume that the executable is available in the PATH.

Note: gh-difftool does not support the difftool.trustExitCode git config option. Exit codes are not trusted.

Tool Path

When the difftool is not in the PATH, it can be specified via the difftool.<tool>.path git config option.

[difftool.sometool]
    path = /path/to/some/difftool

Tool Command

If your difftool of choice is not supported you can explicitly use the difftool.<tool>.cmd option.

[difftool.sometool]
    cmd = /path/to/some/unsupported/difftool --extra-arg=foo $LOCAL $REMOTE

The $LOCAL and $REMOTE variables will be replaced with the paths to the local and remote temporary files.

Unlike the standard git difftool, the difftool.<tool>.cmd used with gh-difftool will not be run in a shell.

This means:

• Only the $LOCAL and $REMOTE variables will be replaced.
• the $LOCAL and $REMOTE variables need to be space separated. Use --local $LOCAL, not --local=$LOCAL.

Requires

• The GitHub CLI, gh
• The patch utility