sparse-checkout: refuse to add to bad patterns

When in cone mode sparse-checkout, it is unclear how 'git
sparse-checkout add <dir1> ...' should behave if the existing
sparse-checkout file does not match the cone mode patterns. Change the
behavior to fail with an error message about the existing patterns.

Also, all cone mode patterns start with a '/' character, so add that
restriction. This is necessary for our example test 'cone mode: warn on
bad pattern', but also requires modifying the example sparse-checkout
file we use to test the warnings related to recognizing cone mode
patterns.

This error checking would cause a failure further down the test script
because of a test that adds non-cone mode patterns without cleaning them
up. Perform that cleanup as part of the test now.

Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/dir.c b/dir.c
index 7e72958d51..eca75e8921 100644
--- a/dir.c
+++ b/dir.c
@@ -727,7 +727,7 @@ static void add_pattern_to_hashsets(struct pattern_list *pl, struct path_pattern
 	}
 
 	if (given->patternlen < 2 ||
-	    *given->pattern == '*' ||
+	    *given->pattern != '/' ||
 	    strstr(given->pattern, "**")) {
 		/* Not a cone pattern. */
 		warning(_("unrecognized pattern: '%s'"), given->pattern);