fix(runtime): Extract error code for all OS error variants (#17958)

cli/tests/unit/read_file_test.ts

@@ -158,3 +158,29 @@ Deno.test(
     assert(data.byteLength > 0);
   },
 );
+
+Deno.test(
+  { permissions: { read: true } },
+  async function readFileNotFoundErrorCode() {
+    try {
+      await Deno.readFile("definitely-not-found.json");
+    } catch (e) {
+      assertEquals(e.code, "ENOENT");
+    }
+  },
+);
+
+Deno.test(
+  { permissions: { read: true } },
+  async function readFileIsDirectoryErrorCode() {
+    try {
+      await Deno.readFile("cli/tests/testdata/assets/");
+    } catch (e) {
+      if (Deno.build.os === "windows") {
+        assertEquals(e.code, "ENOENT");
+      } else {
+        assertEquals(e.code, "EISDIR");
+      }
+    }
+  },
+);

ext/fs/lib.rs

@@ -188,8 +188,8 @@ deno_core::extension!(deno_fs,
   },
 );
 
-fn default_err_mapper(err: Error, desc: String) -> Error {
+fn default_err_mapper(err: Error, desc: String) -> AnyError {
-  Error::new(err.kind(), format!("{err}, {desc}"))
+  AnyError::new(Error::new(err.kind(), desc)).context(err)
 }
 
 #[derive(Deserialize, Default, Debug)]
@@ -1017,7 +1017,7 @@ where
       let mut st = std::mem::zeroed();
       let ret = stat(from.as_ptr(), &mut st);
       if ret != 0 {
-        return Err(err_mapper(Error::last_os_error()).into());
+        return Err(err_mapper(Error::last_os_error()));
       }
 
       if st.st_size > 128 * 1024 {
@@ -2347,9 +2347,9 @@ where
 
   let read_future = tokio::task::spawn_blocking(move || {
     let path = Path::new(&path);
-    Ok(std::fs::read(path).map(ZeroCopyBuf::from).map_err(|err| {
+    std::fs::read(path).map(ZeroCopyBuf::from).map_err(|err| {
       default_err_mapper(err, format!("readfile '{}'", path.display()))
-    })?)
+    })
   });
 
   let cancel_handle = cancel_rid.and_then(|rid| {