fix: support for resolving empty tsconfig file (#602)

back port web-infra-dev/rspack-resolver#55

Co-authored-by: Gengkun <[email protected]>

Author: JounQin

fixtures/tsconfig/cases/empty/index.js

@@ -131,6 +131,22 @@ fn broken() {
     assert_eq!(resolved_path, Err(error));
 }
 
+#[test]
+fn empty() {
+    let f = super::fixture_root().join("tsconfig/cases/empty");
+
+    let resolver = Resolver::new(ResolveOptions {
+        tsconfig: Some(TsconfigOptions {
+            config_file: f.join("tsconfig.json"),
+            references: TsconfigReferences::Auto,
+        }),
+        ..ResolveOptions::default()
+    });
+
+    let resolved_path = resolver.resolve(&f, "./index").map(|f| f.full_path());
+    assert_eq!(resolved_path, Ok(f.join("index.js")));
+}
+
 // <https://github.com/parcel-bundler/parcel/blob/c8f5c97a01f643b4d5c333c02d019ef2618b44a5/packages/utils/node-resolver-rs/src/tsconfig.rs#L193C12-L193C12>
 #[test]
 fn test_paths() {

fixtures/tsconfig/cases/empty/tsconfig.json

@@ -625,7 +625,8 @@ impl TsConfig {
     pub fn parse(root: bool, path: &Path, json: &mut str) -> Result<Self, serde_json::Error> {
         let json = trim_start_matches_mut(json, '\u{feff}'); // strip bom
         _ = json_strip_comments::strip(json);
-        let mut tsconfig: Self = serde_json::from_str(json)?;
+        let mut tsconfig: Self =
+            serde_json::from_str(if json.trim().is_empty() { "{}" } else { json })?;
         tsconfig.root = root;
         tsconfig.path = path.to_path_buf();
         Ok(tsconfig)