Re: [PATCH] builtin-commit: fix partial-commit support

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> ...
> Additionally:

   - read the index file after pre-commit hook returns, as the
     hook can modify it to affect the contents of the commit.

>  - remove the temporary index file .git/next-index-* after
>    commit is done or aborted.
>
>  - run post-commit hook with the real index file to be used
>    after the commit (previously it gave the temporary commit if
>    a partial commit was made).
>
>  - resurrect the safety mechanism to refuse partial commits
>    during a merge to match the scripted version.

>  static char *prepare_index(const char **files, const char *prefix)
>  {
>  	int fd;
>  	struct tree *tree;
> -	struct lock_file *next_index_lock;
> +	struct path_list partial;
> +	const char **pathspec = NULL;
>  
>  	if (interactive) {
>  		interactive_add();
> +		commit_style = COMMIT_NORMAL;

This should be COMMIT_AS_IS, to match the scripted version.

> +	/*
> +	 * A partial commit.
> +	 *
> +	 * (0) find the set of affected paths [NEEDSWORK]

This [NEEDSWORK] has been resolved.

> +	 * (1) get lock on the real index file;
> +	 * (2) update the_index with the given paths;
> +	 * (3) write the_index out to the real index (still locked);
> +	 * (4) get lock on the false index file;
> +	 * (5) reset the_index from HEAD, but keep the addition;

This ", but keep the addition" is no longer necessary; the set
of paths discovered in step (0) _will_ include the added paths
that are named by the user in **files.

> +	 * (6) update the_index the same way as (2);
> +	 * (7) write the_index out to the false index file;
> +	 * (8) return the name of the false index file (still locked);
> +	 *
> +	 * The caller should run hooks on the locked false index, and

 ... "create the commit using the false index", of course.

> +	 * (A) if all goes well, commit the real index;
> +	 * (B) on failure, rollback the real index;
> +	 * In either case, rollback the false index.
> +	 */