Re: [PATCH 4/6] git-sparse-checkout.txt: update to document that set handles init

> From: Elijah Newren <newren@gmail.com>
> 
> As noted in the previous commit, using separate `init` and `set` steps
> with sparse-checkout result in a number of issues.  The previous commit
> made `set` able to handle the work of both commands.  Update the
> documentation to reflect this, and mark `init` as deprecated.
> 
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
>  Documentation/git-sparse-checkout.txt | 92 ++++++++++++++-------------
>  1 file changed, 49 insertions(+), 43 deletions(-)
> 
> diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
> index 42056ee9ff9..d22c925ecf8 100644
> --- a/Documentation/git-sparse-checkout.txt
> +++ b/Documentation/git-sparse-checkout.txt
> @@ -30,28 +30,35 @@ COMMANDS
>  'list'::
>  	Describe the patterns in the sparse-checkout file.
>  
> -'init'::
> -	Enable the `core.sparseCheckout` setting. If the
> -	sparse-checkout file does not exist, then populate it with
> -	patterns that match every file in the root directory and
> -	no other directories, then will remove all directories tracked
> -	by Git. Add patterns to the sparse-checkout file to
> -	repopulate the working directory.
> +'set'::
> +	Enable the necessary config settings
> +	(extensions.worktreeConfig, core.sparseCheckout,
> +	core.sparseCheckoutCone) if they are not already enabled, and
> +	write a set of patterns to the sparse-checkout file from the
> +	list of arguments following the 'set' subcommand. Update the
> +	working directory to match the new patterns.
>  +
> -To avoid interfering with other worktrees, it first enables the
> -`extensions.worktreeConfig` setting and makes sure to set the
> -`core.sparseCheckout` setting in the worktree-specific config file.
> +When the `--stdin` option is provided, the patterns are read from
> +standard in as a newline-delimited list instead of from the arguments.
>  +
> -When `--cone` is provided, the `core.sparseCheckoutCone` setting is
> -also set, allowing for better performance with a limited set of
> -patterns (see 'CONE PATTERN SET' below).
> +When `--cone` is passed or `core.sparseCheckoutCone` is enabled, the
> +input list is considered a list of directories instead of
> +sparse-checkout patterns.  This allows for better performance with a
> +limited set of patterns (see 'CONE PATTERN SET' below).  Note that the
> +set command will write patterns to the sparse-checkout file to include
> +all files contained in those directories (recursively) as well as
> +files that are siblings of ancestor directories. The input format
> +matches the output of `git ls-tree --name-only`.  This includes
> +interpreting pathnames that begin with a double quote (") as C-style
> +quoted strings.
>  +
> -Use the `--[no-]sparse-index` option to toggle the use of the sparse
> -index format. This reduces the size of the index to be more closely
> -aligned with your sparse-checkout definition. This can have significant
> -performance advantages for commands such as `git status` or `git add`.
> -This feature is still experimental. Some commands might be slower with
> -a sparse index until they are properly integrated with the feature.
> +Use the `--[no-]sparse-index` option to use a sparse index (the
> +default is to not use it).  A sparse index reduces the size of the
> +index to be more closely aligned with your sparse-checkout
> +definition. This can have significant performance advantages for
> +commands such as `git status` or `git add`.  This feature is still
> +experimental. Some commands might be slower with a sparse index until
> +they are properly integrated with the feature.
>  +
>  **WARNING:** Using a sparse index requires modifying the index in a way
>  that is not completely understood by external tools. If you have trouble
> @@ -60,23 +67,6 @@ to rewrite your index to not be sparse. Older versions of Git will not
>  understand the sparse directory entries index extension and may fail to
>  interact with your repository until it is disabled.
>  
> -'set'::
> -	Write a set of patterns to the sparse-checkout file, as given as
> -	a list of arguments following the 'set' subcommand. Update the
> -	working directory to match the new patterns. Enable the
> -	core.sparseCheckout config setting if it is not already enabled.
> -+
> -When the `--stdin` option is provided, the patterns are read from
> -standard in as a newline-delimited list instead of from the arguments.
> -+
> -When `core.sparseCheckoutCone` is enabled, the input list is considered a
> -list of directories instead of sparse-checkout patterns. The command writes
> -patterns to the sparse-checkout file to include all files contained in those
> -directories (recursively) as well as files that are siblings of ancestor
> -directories. The input format matches the output of `git ls-tree --name-only`.
> -This includes interpreting pathnames that begin with a double quote (") as
> -C-style quoted strings.
> -
>  'add'::
>  	Update the sparse-checkout file to include additional patterns.
>  	By default, these patterns are read from the command-line arguments,
> @@ -96,9 +86,27 @@ C-style quoted strings.
>  
>  'disable'::
>  	Disable the `core.sparseCheckout` config setting, and restore the
> -	working directory to include all files. Leaves the sparse-checkout
> -	file intact so a later 'git sparse-checkout init' command may
> -	return the working directory to the same state.
> +	working directory to include all files.
> +
> +'init'::
> +	Deprecated command that behaves like `set` with no specified paths.
> +	May be removed in the future.

> ++
> +Historically, `set` did not used to handle all the necessary config
> +settings, which meant that both `init` and `set` had to be called.
> +Invoking both meant the `init` step would first remove nearly all
> +tracked files (and in cone mode, ignored files too), then the `set`
> +step would add many of the tracked files (but not ignored files) back.
> +In addition to the lost files, the performance and UI of this
> +combination was poor.
> ++
> +Also, historically, `init` would not actually initialize the
> +sparse-checkout file if it already existed.  This meant it was
> +possible to return to a sparse-checkout without remembering which
> +paths to pass to a subsequent 'set' or 'add' command.  However,
> +`--cone` and `--sparse-index` options would not be remembered across
> +the disable command, so the easy restore of calling a plain `init`
> +decreased in utility.
>  
>  SPARSE CHECKOUT
>  ---------------
> @@ -117,10 +125,8 @@ directory, it updates the skip-worktree bits in the index based
>  on this file. The files matching the patterns in the file will
>  appear in the working directory, and the rest will not.
>  
> -To enable the sparse-checkout feature, run `git sparse-checkout init` to
> -initialize a simple sparse-checkout file and enable the `core.sparseCheckout`
> -config setting. Then, run `git sparse-checkout set` to modify the patterns in
> -the sparse-checkout file.
> +To enable the sparse-checkout feature, run `git sparse-checkout set` to
> +set the patterns you want to use.
>  
>  To repopulate the working directory with all files, use the
>  `git sparse-checkout disable` command.
>