Re: [PATCH v5 08/17] sparse-checkout: add 'cone' mode

> diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
> index f794d4797a..3931e4f2ad 100644
> --- a/Documentation/git-sparse-checkout.txt
> +++ b/Documentation/git-sparse-checkout.txt
> @@ -92,6 +92,56 @@ using negative patterns. For example, to remove the file `unwanted`:
>  ----------------
>  
>  
> +## CONE PATTERN SET
> +
> +The full pattern set allows for arbitrary pattern matches and complicated
> +inclusion/exclusion rules. These can result in O(N*M) pattern matches when
> +updating the index, where N is the number of patterns and M is the number
> +of paths in the index. To combat this performance issue, a more restricted
> +pattern set is allowed when `core.spareCheckoutCone` is enabled.
> +
> +The accepted patterns in the cone pattern set are:
> +
> +1. *Recursive:* All paths inside a directory are included.
> +
> +2. *Parent:* All files immediately inside a directory are included.
> +
> +In addition to the above two patterns, we also expect that all files in the
> +root directory are included. If a recursive pattern is added, then all
> +leading directories are added as parent patterns.
> +
> +By default, when running `git sparse-checkout init`, the root directory is
> +added as a parent pattern. At this point, the sparse-checkout file contains
> +the following patterns:
> +
> +```
> +/*
> +!/*/
> +```
> +
> +This says "include everything in root, but nothing two levels below root."
> +If we then add the folder `A/B/C` as a recursive pattern, the folders `A` and
> +`A/B` are added as parent patterns. The resulting sparse-checkout file is
> +now
> +
> +```
> +/*
> +!/*/
> +/A/
> +!/A/*/
> +/A/B/
> +!/A/B/*/
> +/A/B/C/
> +```