ignore: honor case insensitivity for negative ignores

When computing negative ignores, we throw away any rule which does not
undo a previous rule to optimize. But on case insensitive file systems,
we need to keep in mind that a negative ignore can also undo a previous
rule with different case, which we did not yet honor while determining
whether a rule undoes a previous one. So in the following example, we
fail to unignore the "/Case" directory:

    /case
    !/Case

Make both paths checking whether a plain- or wildcard-based rule undo a
previous rule aware of case-insensitivity. This fixes the described
issue.

1 files changed, 34 insertions, 0 deletions

diff --git a/tests/attr/ignore.c b/tests/attr/ignore.c
index 5adfaf557..856e61f90 100644
--- a/tests/attr/ignore.c
+++ b/tests/attr/ignore.c
@@ -312,3 +312,37 @@ void test_attr_ignore__unignore_dir_succeeds(void)
 	assert_is_ignored(false, "src/foo.c");
 	assert_is_ignored(true, "src/foo/foo.c");
 }
+
+void test_attr_ignore__case_insensitive_unignores_previous_rule(void)
+{
+	git_config *cfg;
+
+	cl_git_rewritefile("attr/.gitignore",
+		"/case\n"
+		"!/Case/\n");
+
+	cl_git_pass(git_repository_config(&cfg, g_repo));
+	cl_git_pass(git_config_set_bool(cfg, "core.ignorecase", true));
+
+	cl_must_pass(p_mkdir("attr/case", 0755));
+	cl_git_mkfile("attr/case/file", "content");
+
+	assert_is_ignored(false, "case/file");
+}
+
+void test_attr_ignore__case_sensitive_unignore_does_nothing(void)
+{
+	git_config *cfg;
+
+	cl_git_rewritefile("attr/.gitignore",
+		"/case\n"
+		"!/Case/\n");
+
+	cl_git_pass(git_repository_config(&cfg, g_repo));
+	cl_git_pass(git_config_set_bool(cfg, "core.ignorecase", false));
+
+	cl_must_pass(p_mkdir("attr/case", 0755));
+	cl_git_mkfile("attr/case/file", "content");
+
+	assert_is_ignored(true, "case/file");
+}