sparse-checkout: work with Windows paths

When using Windows, a user may run 'git sparse-checkout set A\B\C'
to add the Unix-style path A/B/C to their sparse-checkout patterns.
Normalizing the input path converts the backslashes to slashes before we
add the string 'A/B/C' to the recursive hashset.

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

builtin/sparse-checkout.c

@@ -394,6 +394,9 @@ static void strbuf_to_cone_pattern(struct strbuf *line, struct pattern_list *pl)
 
 	strbuf_trim_trailing_dir_sep(line);
 
+	if (strbuf_normalize_path(line))
+		die(_("could not normalize path %s"), line->buf);
+
 	if (!line->len)
 		return;
 

t/t1091-sparse-checkout-builtin.sh

@@ -497,4 +497,18 @@ test_expect_success BSLASHPSPEC 'pattern-checks: escaped characters' '
 	test_cmp list-expect list-actual
 '
 
+test_expect_success MINGW 'cone mode replaces backslashes with slashes' '
+	git -C repo sparse-checkout set deep\\deeper1 &&
+	cat >expect <<-\EOF &&
+	/*
+	!/*/
+	/deep/
+	!/deep/*/
+	/deep/deeper1/
+	EOF
+	test_cmp expect repo/.git/info/sparse-checkout &&
+	check_files repo a deep &&
+	check_files repo/deep a deeper1
+'
+
 test_done