Re: [PATCH 1/2] refs: Add for_each_worktree_ref for iterating over all worktree HEADs

> From: Manish Goregaokar <manishearth@gmail.com>
>
> To ensure that `git prune` does not remove refs checked out
> in other worktrees, we need to include these HEADs in the
> set of roots. This adds the iteration function necessary
> to do this.
>
> Signed-off-by: Manish Goregaokar <manishearth@gmail.com>
> ---
>  refs.c | 16 ++++++++++++++++
>  refs.h |  1 +
>  2 files changed, 17 insertions(+)
>
> diff --git a/refs.c b/refs.c
> index 2d71774..27e0b60 100644
> --- a/refs.c
> +++ b/refs.c
> @@ -3,6 +3,7 @@
>   */
>
>  #include "cache.h"
> +#include "commit.h"
>  #include "lockfile.h"
>  #include "refs.h"
>  #include "refs/refs-internal.h"
> @@ -1157,6 +1158,21 @@ int head_ref(each_ref_fn fn, void *cb_data)
>         return head_ref_submodule(NULL, fn, cb_data);
>  }
>
> +int for_each_worktree_ref(each_ref_fn fn, void *cb_data)
> +{
> +       int i, flag, retval;
> +       struct object_id oid;
> +       struct worktree **worktrees = get_worktrees(GWT_SORT_LINKED);
> +       for (i = 0; worktrees[i]; i++) {
> +               struct commit* commit = lookup_commit_reference(worktrees[i]->head_sha1);
> +               oid = commit->object.oid;
> +               if (!read_ref_full("HEAD", RESOLVE_REF_READING, oid.hash, &flag)) {
> +                       if (retval = fn("HEAD", &oid, flag, cb_data))
> +                               return retval;
> +               }
> +       }
> +}
> +
>  /*
>   * Call fn for each reference in the specified submodule for which the
>   * refname begins with prefix. If trim is non-zero, then trim that
> diff --git a/refs.h b/refs.h
> index 9fbff90..425a853 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -192,6 +192,7 @@ typedef int each_ref_fn(const char *refname,
>   * stop the iteration.
>   */
>  int head_ref(each_ref_fn fn, void *cb_data);
> +int for_each_worktree_ref(each_ref_fn fn, void *cb_data);
>  int for_each_ref(each_ref_fn fn, void *cb_data);
>  int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data);
>  int for_each_fullref_in(const char *prefix, each_ref_fn fn, void *cb_data,
> --
> 2.10.1
>