fix(linter): nested configuration directory resolution (#10157)

Fixes #10156

I'm not very familiar with the inner workings of this project - this was
a fix based on what I could understand after exploring the codebase for
the first time. @camchenry It would be great to get your eyes on this
since you are familiar with the nested config implementation.

Author: zubhav

apps/oxlint/src/lint.rs

@@ -176,15 +176,19 @@ impl Runner for LintRunner {
 
         if use_nested_config {
             // get all of the unique directories among the paths to use for search for
-            // oxlint config files in those directories
-            // e.g. `/some/file.js` and `/some/other/file.js` would both result in `/some`
+            // oxlint config files in those directories and their ancestors
+            // e.g. `/some/file.js` will check `/some` and `/`
+            //      `/some/other/file.js` will check `/some/other`, `/some`, and `/`
             let mut directories = FxHashSet::default();
             for path in &paths {
                 let path = Path::new(path);
-                if let Some(directory) = path.parent() {
+                // Start from the file's parent directory and walk up the tree
+                let mut current = path.parent();
+                while let Some(dir) = current {
                     // NOTE: Initial benchmarking showed that it was faster to iterate over the directories twice
                     // rather than constructing the configs in one iteration. It's worth re-benchmarking that though.
-                    directories.insert(directory);
+                    directories.insert(dir);
+                    current = dir.parent();
                 }
             }
             for directory in directories {
@@ -1009,6 +1013,14 @@ mod test {
         Tester::new().with_cwd("fixtures/extends_config".into()).test_and_snapshot(args);
     }
 
+    #[test]
+    fn test_nested_config_subdirectory() {
+        // This tests the specific scenario from issue #10156
+        // where a file is located in a subdirectory of a directory with a config file
+        let args = &["package3-deep-config"];
+        Tester::new().with_cwd("fixtures/nested_config".into()).test_and_snapshot(args);
+    }
+
     #[test]
     fn test_nested_config_explicit_config_precedence() {
         // `--config` takes absolute precedence over nested configs, and will be used for

apps/oxlint/src/snapshots/fixtures__nested_config_package3-deep-config@oxlint.snap

@@ -0,0 +1,22 @@
+---
+source: apps/oxlint/src/tester.rs
+---
+########## 
+arguments: package3-deep-config
+working directory: fixtures/nested_config
+----------
+
+  x ]8;;https://oxc.rs/docs/guide/usage/linter/rules/eslint/no-console.html\eslint(no-console)]8;;\: eslint(no-console): Unexpected console statement.
+   ,-[package3-deep-config/src/components/component.js:2:3]
+ 1 | export function Component() {
+ 2 |   console.log("hello");
+   :   ^^^^^^^^^^^
+ 3 | }
+   `----
+  help: Delete this console statement.
+
+Found 0 warnings and 1 error.
+Finished in <variable>ms on 1 file using 1 threads.
+----------
+CLI result: LintFoundErrors
+----------