Subject: [PATCH v2 08/16] restore: default to --source=HEAD when only --staged is specified

From: Nguyễn Thái Ngọc Duy <[email-masked]>
Date: Thu, 11 Apr 2019 20:12:10 +0700

"git restore --staged" without --source does not make much sense since
by default we restore from the index.  Instead of copying the index to
itself, set the default source to HEAD in this case, yielding behavior
that matches "git reset -- <paths>".

Signed-off-by: Nguyễn Thái Ngọc Duy <[email-masked]>
---
 builtin/checkout.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 71e2589340..09a03f1ff8 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -1524,6 +1524,12 @@ static int checkout_main(int argc, const char **argv, const char *prefix,
 	}
 	if (opts->checkout_index < 0 || opts->checkout_worktree < 0)
 		BUG("these flags should be non-negative by now");
+	/*
+	 * convenient shortcut: "git restore --staged" equals
+	 * "git restore --staged --source HEAD"
+	 */
+	if (!opts->from_treeish && opts->checkout_index && !opts->checkout_worktree)
+		opts->from_treeish = "HEAD";
 
 	/*
 	 * From here on, new_branch will contain the branch to be checked out,
-- 
2.21.0.682.g30d2204636