Re: [PATCH 2/3] setup: have the_repository use the_index

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 12, 2017, 00:11 UTC
Message-ID: <xmqqzica1pli.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20170711220408.173269-3-bmwill@google.com>

Brandon Williams <bmwill@google.com> writes:

Show 22 quoted lines

> Have the index state which is stored in 'the_repository' be a pointer to
> the in-core instead 'the_index'.  This makes it easier to begin
> transitioning more parts of the code base to operate on a 'struct
> repository'.
>
> Signed-off-by: Brandon Williams <bmwill@google.com>
> ---
>  setup.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/setup.c b/setup.c
> index 860507e1f..b370bf3c1 100644
> --- a/setup.c
> +++ b/setup.c
> @@ -1123,6 +1123,7 @@ const char *setup_git_directory_gently(int *nongit_ok)
>  			setup_git_env();
>  		}
>  	}
> +	the_repository->index = &the_index;
>  
>  	strbuf_release(&dir);
>  	strbuf_release(&gitdir);

I would have expected this to be going in the different direction, i.e. there is an embedded instance of index_state in a repository object, and the_repository.index is defined to be the old the_index, i.e.

	#define the_index (the_repository.index)

When a Git command that recurses into submodules in-core using the_repository that represents the top-level superproject and another repository object tht represents a submodule, don't we want the repository object for the submodule also have its own default index without having to allocate one and point at it with the index field?

I dunno. Being able to leave the index field NULL lets you say "this is a bare repository and there is no place for the index file for it", but even if we never write out the in-core index to an index file on disk, being able to populate the in-core index that is default for the repository object from a tree-ish and iterating over it (e.g. running in-core merge of trees) is a useful thing to do, so I do not consider "index field can be set to NULL to signify a bare repository" a very strong plus.