Fix whitelisting in pathed globs

lib/src/filter/tagged.rs

@@ -286,7 +286,6 @@ impl TaggedFilterer {
 	// /foo/bar                /foo/bar/baz.txt          /baz.*                 pass
 	// /foo/bar                /foo/bar/baz.txt          /blah                  fail
 	// /foo/quz                /foo/bar/baz.txt          /baz.*                 skip
-	// TODO: lots of tests
 
 	// Ok(Some(bool)) => the match was applied, bool is the result
 	// Ok(None) => for some precondition, the match was not done (mismatched tag, out of context, …)
@@ -422,7 +421,11 @@ impl TaggedFilterer {
 
 		let mut builder = GitignoreBuilder::new(&self.origin);
 		for filter in globs {
-			if let Pattern::Glob(glob) = filter.pat {
+			if let Pattern::Glob(mut glob) = filter.pat {
+				if filter.negate {
+					glob.insert(0, '!');
+				}
+
 				trace!(?op_filter, in_path=?filter.in_path, ?glob, "adding new glob line");
 				builder
 					.add_line(filter.in_path, &glob)

lib/tests/filter_tagged_ignorefiles.rs

@@ -277,3 +277,33 @@ async fn globs() {
 	filterer.file_doesnt_pass("song/bird/bananas");
 	filterer.dir_doesnt_pass("song/bird/bananas");
 }
+
+#[tokio::test]
+async fn negate() {
+	let filterer = filt("", &[file("negate")]).await;
+
+	filterer.file_does_pass("yeah");
+	filterer.file_doesnt_pass("nah");
+	filterer.file_does_pass("nah.yeah");
+}
+
+#[tokio::test]
+async fn allowlist() {
+	let filterer = filt("", &[file("allowlist")]).await;
+
+	filterer.file_does_pass("mod.go");
+	filterer.file_does_pass("foo.go");
+	filterer.file_does_pass("go.sum");
+	filterer.file_does_pass("go.mod");
+	filterer.file_does_pass("README.md");
+	filterer.file_does_pass("LICENSE");
+	filterer.file_does_pass(".gitignore");
+
+	filterer.file_doesnt_pass("evil.sum");
+	filterer.file_doesnt_pass("evil.mod");
+	filterer.file_doesnt_pass("gofile.gone");
+	filterer.file_doesnt_pass("go.js");
+	filterer.file_doesnt_pass("README.asciidoc");
+	filterer.file_doesnt_pass("LICENSE.txt");
+	filterer.file_doesnt_pass("foo/.gitignore");
+}

lib/tests/ignores/allowlist

@@ -0,0 +1,14 @@
+# from https://github.com/github/gitignore
+
+*
+
+!/.gitignore
+
+!*.go
+!go.sum
+!go.mod
+
+!README.md
+!LICENSE
+
+!*/

lib/tests/ignores/negate

@@ -0,0 +1,2 @@
+nah
+!nah.yeah