sparse-checkout: 'set' subcommand

The 'git sparse-checkout set' subcommand takes a list of patterns
as arguments and writes them to the sparse-checkout file. Then, it
updates the working directory using 'git read-tree -mu HEAD'.

The 'set' subcommand will replace the entire contents of the
sparse-checkout file. The write_patterns_and_update() method is
extracted from cmd_sparse_checkout() to make it easier to implement
'add' and/or 'remove' subcommands in the future.

If the core.sparseCheckout config setting is disabled, then enable
the config setting in the worktree config. If we set the config
this way and the sparse-checkout fails, then re-disable the config
setting.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/git-sparse-checkout.txt b/Documentation/git-sparse-checkout.txt
index 491be1345f..ca62669b8c 100644
--- a/Documentation/git-sparse-checkout.txt
+++ b/Documentation/git-sparse-checkout.txt
@@ -42,6 +42,12 @@ 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.
 
+'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.
+
 SPARSE CHECKOUT
 ---------------