Fix whitelisting precedence.

Once a file is known to be whitelisted, we shouldn't check any ancestor
gitignores.

src/ignore.rs

@@ -217,17 +217,25 @@ impl Ignore {
             return true;
         }
         if !self.no_ignore {
+            let mut whitelisted = false;
             for id in self.stack.iter().rev() {
                 let mat = id.matched(path, is_dir);
+                // println!("path: {}, mat: {:?}, id: {:?}",
+                         // path.display(), mat, id);
                 if let Some(is_ignored) = self.ignore_match(path, mat) {
                     if is_ignored {
                         return true;
                     }
                     // If this path is whitelisted by an ignore, then
                     // fallthrough and let the file type matcher have a say.
+                    whitelisted = true;
                     break;
                 }
             }
+            // If the file has been whitelisted, then we have to stop checking
+            // parent directories. The only thing that can override a whitelist
+            // at this point is a type filter.
+            if !whitelisted {
                 let mut path = path.to_path_buf();
                 for id in self.parent_stack.iter().rev() {
                     if let Some(ref dirname) = id.name {
@@ -239,11 +247,13 @@ impl Ignore {
                             return true;
                         }
                         // If this path is whitelisted by an ignore, then
-                    // fallthrough and let the file type matcher have a say.
+                        // fallthrough and let the file type matcher have a
+                        // say.
                         break;
                     }
                 }
             }
+        }
         let mat = self.types.matched(path, is_dir);
         if let Some(is_ignored) = self.ignore_match(path, mat) {
             return is_ignored;