From 388c1ae4a5e0a939e5973505855233143ad460eb Mon Sep 17 00:00:00 2001
From: OkaYu <aiueo13>
Date: Thu, 12 Feb 2026 07:13:10 +0900
Subject: [PATCH] fix(fs): change to reject if unsupported encodings in
 readTextFileLines

---
 ...upported-encodings-in-readTextFileLines.md |  6 +++++
 plugins/fs/guest-js/index.ts                  | 26 +++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 .changes/change-to-reject-if-unsupported-encodings-in-readTextFileLines.md

diff --git a/.changes/change-to-reject-if-unsupported-encodings-in-readTextFileLines.md b/.changes/change-to-reject-if-unsupported-encodings-in-readTextFileLines.md
new file mode 100644
index 0000000000..901c618198
--- /dev/null
+++ b/.changes/change-to-reject-if-unsupported-encodings-in-readTextFileLines.md
@@ -0,0 +1,6 @@
+---
+"fs": pach
+"fs-js": pach
+---
+
+Change to reject if unsupported encodings in readTextFileLines
diff --git a/plugins/fs/guest-js/index.ts b/plugins/fs/guest-js/index.ts
index 64e53fa313..e6c1682881 100644
--- a/plugins/fs/guest-js/index.ts
+++ b/plugins/fs/guest-js/index.ts
@@ -782,6 +782,28 @@ async function readTextFile(
   return new TextDecoder(options?.encoding ?? 'utf-8').decode(bytes)
 }
 
+/**
+ * Asserts that the given encoding is ASCII-compatible for LF (0x0A) and CR (0x0D).
+ *
+ * @throws if the encoding is UTF-16, "replacement", or otherwise invalid.
+ */
+function assertLfCrAsciiCompatibleEncoding(encodingLabel?: string): void {
+  // Normalize the encoding label.
+  // If it is invalid, a RangeError is thrown here.
+  const encoding = (new TextDecoder(encodingLabel)).encoding
+
+  // Reject encodings defined in the Web Encoding Standard
+  // that do not represent LF and CR as 0x0A and 0x0D.
+  // https://developer.mozilla.org/en-US/docs/Web/API/Encoding_API/Encodings
+  if (
+    encoding === "utf-16le" ||
+    encoding === "utf-16be" ||
+    encoding === "replacement"
+  ) {
+    throw new Error(`Unsupported encoding label: ${encodingLabel}`)
+  }
+}
+
 /**
  * Returns an async {@linkcode AsyncIterableIterator} over the lines of a file, decoded using the specified encoding (default: UTF-8).
  * @example
@@ -804,6 +826,10 @@ async function readTextFileLines(
   if (path instanceof URL && path.protocol !== 'file:') {
     throw new TypeError('Must be a file URL.')
   }
+  if (options?.encoding != null) {
+    // https://github.com/tauri-apps/plugins-workspace/pull/3244#issuecomment-3869568792
+    assertLfCrAsciiCompatibleEncoding(options.encoding)
+  }
 
   const pathStr = path instanceof URL ? path.toString() : path