Re: [PATCH v3 3/8] update-index: add --force-full-index option for expand/collapse test

> From: Victoria Dye <vdye@github.com>
> 
> Add a new `--force-full-index` option to `git update-index`, which skips
> explicitly setting `command_requires_full_index`. This option, intended for
> use in internal testing purposes only, lets `git update-index` run as a
> command without sparse index compatibility implemented, even after it
> receives updates to otherwise use the sparse index.
> 
> The specific test `--force-full-index` is intended for - `t1092 -
> sparse-index is expanded and converted back` - verifies index compatibility
> in commands that do not change the default (enabled)
> `command_requires_full_index` repo setting. In the past, the test used `git
> reset`. However, as `reset` and other commands are integrated with the
> sparse index, the command used in the test would need to keep changing.
> Conversely, the `--force-full-index` option makes `git update-index` behave
> like a not-yet-sparse-aware command, and can be used in the test
> indefinitely without interfering with future sparse index integrations.
> 
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Signed-off-by: Victoria Dye <vdye@github.com>