fix(sdk): decode command output as GBK when it is not valid UTF-8 (#1735)

packages/plugin-sdk/src/host-commands.ts

@@ -21,6 +21,30 @@ export interface ExecResult {
   code: number | null;
 }
 
+/**
+ * Decodes raw command output. Strict UTF-8 first; when that fails, tries GBK,
+ * which is what a Chinese-locale Windows console sends (its bytes are almost
+ * never valid UTF-8) and keeps it only when it decodes without replacement
+ * characters. Anything else falls back to lossy UTF-8, the old behavior.
+ */
+export function decodeCommandOutput(buf: Buffer): string {
+  try {
+    return new TextDecoder("utf-8", { fatal: true, ignoreBOM: true }).decode(
+      buf,
+    );
+  } catch {
+    // not valid UTF-8, try the legacy codepage
+  }
+  try {
+    // A Node built with small-ICU has no GBK decoder and throws here.
+    const gbk = new TextDecoder("gbk").decode(buf);
+    if (!gbk.includes("�")) return gbk;
+  } catch {
+    // expected - fall through to lossy UTF-8
+  }
+  return buf.toString("utf8");
+}
+
 /** Runs one non-interactive command over an existing ssh2 client. */
 export function execCommand(
   client: Client,
@@ -65,8 +89,10 @@ export function execCommand(
       }
 
       stream = _stream;
-      let stdout = "";
-      let stderr = "";
+      // Chunks are buffered and decoded once on close: a multi-byte character
+      // can be split across chunks, and charset detection needs it whole.
+      const stdout: Buffer[] = [];
+      const stderr: Buffer[] = [];
       let exitCode: number | null = null;
 
       stream
@@ -75,11 +101,15 @@ export function execCommand(
             settled = true;
             exitCode = typeof code === "number" ? code : null;
             cleanup();
-            resolve({ stdout, stderr, code: exitCode });
+            resolve({
+              stdout: decodeCommandOutput(Buffer.concat(stdout)),
+              stderr: decodeCommandOutput(Buffer.concat(stderr)),
+              code: exitCode,
+            });
           }
         })
         .on("data", (data: Buffer) => {
-          stdout += data.toString("utf8");
+          stdout.push(data);
         })
         .on("error", (streamErr: Error) => {
           if (!settled) {
@@ -92,7 +122,7 @@ export function execCommand(
       if (stream.stderr) {
         stream.stderr
           .on("data", (data: Buffer) => {
-            stderr += data.toString("utf8");
+            stderr.push(data);
           })
           .on("error", (stderrErr: Error) => {
             if (!settled) {