Fix leading slash bug when used with !.

When writing paths like `!/foo` in gitignore files (or when using the
-g/--glob flag), the presence of `!` would prevent the gitignore builder
from noticing the leading slash, which causes absolute path matching to
fail.

Fixes #405

ignore/src/gitignore.rs

@@ -368,9 +368,10 @@ impl GitignoreBuilder {
         };
         let mut literal_separator = false;
         let has_slash = line.chars().any(|c| c == '/');
-        let is_absolute = line.chars().nth(0).unwrap() == '/';
+        let mut is_absolute = false;
         if line.starts_with("\\!") || line.starts_with("\\#") {
             line = &line[1..];
+            is_absolute = line.chars().nth(0) == Some('/');
         } else {
             if line.starts_with("!") {
                 glob.is_whitelist = true;
@@ -383,6 +384,7 @@ impl GitignoreBuilder {
                 // simply banning wildcards from matching /.
                 literal_separator = true;
                 line = &line[1..];
+                is_absolute = true;
             }
         }
         // If it ends with a slash, then this should only match directories,
@@ -570,6 +572,7 @@ mod tests {
     not_ignored!(
         ignot14, "./third_party/protobuf", "m4/ltoptions.m4",
         "./third_party/protobuf/csharp/src/packages/repositories.config");
+    not_ignored!(ignot15, ROOT, "!/bar", "foo/bar");
 
     fn bytes(s: &str) -> Vec<u8> {
         s.to_string().into_bytes()

ignore/src/overrides.rs

@@ -214,4 +214,10 @@ mod tests {
         assert!(ov.matched("src/foo", false).is_ignore());
         assert!(ov.matched("src/foo", true).is_none());
     }
+
+    #[test]
+    fn absolute_path() {
+        let ov = ov(&["!/bar"]);
+        assert!(ov.matched("./foo/bar", false).is_none());
+    }
 }

tests/tests.rs

@@ -1045,6 +1045,18 @@ clean!(regression_279, "test", ".", |wd: WorkDir, mut cmd: Command| {
     assert_eq!(lines, "");
 });
 
+// See: https://github.com/BurntSushi/ripgrep/issues/405
+clean!(regression_405, "test", ".", |wd: WorkDir, mut cmd: Command| {
+    wd.create_dir("foo/bar");
+    wd.create_dir("bar/foo");
+    wd.create("foo/bar/file1.txt", "test");
+    wd.create("bar/foo/file2.txt", "test");
+    cmd.arg("-g").arg("!/foo/**");
+
+    let lines: String = wd.stdout(&mut cmd);
+    assert_eq!(lines, "bar/foo/file2.txt:test\n");
+});
+
 // See: https://github.com/BurntSushi/ripgrep/issues/7
 sherlock!(feature_7, "-fpat", "sherlock", |wd: WorkDir, mut cmd: Command| {
     wd.create("pat", "Sherlock\nHolmes");