On 11/18, Thomas Gummerer wrote:
> Currently 'git worktree add <path> <branch>', errors out when 'branch'
> is not a local branch. It has no additional dwim'ing features that one
> might expect.
>
> Make it behave more like 'git checkout <branch>' when the branch doesn't
> exist locally, but a remote tracking branch uniquely matches the desired
> branch name, i.e. create a new branch from the remote tracking branch
> and set the upstream to the remote tracking branch.
>
> As 'git worktree add' currently just dies in this situation, there are
> no backwards compatibility worries when introducing this feature.
>
> Signed-off-by: Thomas Gummerer <t.gummerer@xxxxxxxxx>
> ---
> Documentation/git-worktree.txt | 7 +++++++
> builtin/worktree.c | 15 ++++++++++++++
> t/t2025-worktree-add.sh | 44 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 66 insertions(+)
>
> diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
> index b472acc356..3c7c8c3cee 100644
> --- a/Documentation/git-worktree.txt
> +++ b/Documentation/git-worktree.txt
> @@ -52,6 +52,13 @@ is linked to the current repository, sharing everything except working
> directory specific files such as HEAD, index, etc. `-` may also be
> specified as `<branch>`; it is synonymous with `@{-1}`.
> +
> +If <branch> is not found but there does exist a tracking branch in
> +exactly one remote (call it <remote>) with a matching name, treat as
> +equivalent to
> +------------
> +$ git worktree add -b <branch> <path> <remote>/<branch>
> +------------
> ++
> If `<branch>` is omitted and neither `-b` nor `-B` nor `--detach` used,
> then, as a convenience, a new branch based at HEAD is created automatically,
> as if `-b $(basename <path>)` was specified.
> diff --git a/builtin/worktree.c b/builtin/worktree.c
> index 7b9307aa58..92b583ae39 100644
> --- a/builtin/worktree.c
> +++ b/builtin/worktree.c
> @@ -1,4 +1,5 @@
> #include "cache.h"
> +#include "checkout.h"
> #include "config.h"
> #include "builtin.h"
> #include "dir.h"
> @@ -386,6 +387,20 @@ static int add(int ac, const char **av, const char *prefix)
> opts.new_branch = xstrndup(s, n);
> }
>
> + if (ac == 2) {
Err I just realized this doesn't quite make sense. Similar to the
dwim for 'git worktree add <path>', this condition should include
'!opts.new_branch && !opts.detach'. In these cases it's still better
to error out, as the user explicitly asked for a new branch with a
different name/asked not to be put onto a branch. I'll send a v3 with
this fixed in a bit.
> + struct object_id oid;
> + struct commit *commit;
> + const char *remote;
> +
> + commit = lookup_commit_reference_by_name(branch);
> + if (!commit)
> + remote = unique_tracking_name(branch, &oid);
> + if (!commit && remote) {
> + opts.new_branch = branch;
> + branch = remote;
> + }
> + }
> +
> if (opts.new_branch) {
> struct child_process cp = CHILD_PROCESS_INIT;
> cp.git_cmd = 1;
> diff --git a/t/t2025-worktree-add.sh b/t/t2025-worktree-add.sh
> index b5c47ac602..e5959800c0 100755
> --- a/t/t2025-worktree-add.sh
> +++ b/t/t2025-worktree-add.sh
> @@ -6,6 +6,16 @@ test_description='test git worktree add'
>
> . "$TEST_DIRECTORY"/lib-rebase.sh
>
> +# Is branch "refs/heads/$1" set to pull from "$2/$3"?
> +test_branch_upstream () {
> + printf "%s\n" "$2" "refs/heads/$3" >expect.upstream &&
> + {
> + git config "branch.$1.remote" &&
> + git config "branch.$1.merge"
> + } >actual.upstream &&
> + test_cmp expect.upstream actual.upstream
> +}
> +
> test_expect_success 'setup' '
> test_commit init
> '
> @@ -314,4 +324,38 @@ test_expect_success 'rename a branch under bisect not allowed' '
> test_must_fail git branch -M under-bisect bisect-with-new-name
> '
>
> +test_expect_success '"add" <path> <non-existent-branch> fails' '
> + test_must_fail git worktree add foo non-existent
> +'
> +
> +test_expect_success '"add" <path> <branch> dwims' '
> + test_when_finished rm -rf repo_upstream &&
> + test_when_finished rm -rf repo_dwim &&
> + test_when_finished rm -rf foo &&
> + git init repo_upstream &&
> + (
> + cd repo_upstream &&
> + test_commit upstream_master &&
> + git checkout -b foo &&
> + test_commit a_foo
> + ) &&
> + git init repo_dwim &&
> + (
> + cd repo_dwim &&
> + test_commit dwim_master &&
> + git remote add repo_upstream ../repo_upstream &&
> + git config remote.repo_upstream.fetch \
> + "refs/heads/*:refs/remotes/repo_upstream/*" &&
> + git fetch --all &&
> + git worktree add ../foo foo
> + ) &&
> + (
> + cd foo &&
> + test_branch_upstream foo repo_upstream foo &&
> + git rev-parse repo_upstream/foo >expect &&
> + git rev-parse foo >actual &&
> + test_cmp expect actual
> + )
> +'
> +
> test_done
> --
> 2.15.0.345.gf926f18f3d
>
