fix: use fs backend for host apply-patch

scripts/src/ssh.test.ts

@@ -1,5 +1,7 @@
+import { createHash } from "node:crypto";
 import { describe, expect, test } from "bun:test";
 import {
+  createPosixApplyPatchFileSystem,
   createSshStdoutForwarder,
   formatSshStdoutTruncationHint,
   parseSshInvocation,
@@ -9,6 +11,10 @@ import {
   windowsPowerShellScriptPrelude,
 } from "./ssh";
 
+function sha256Hex(text: string): string {
+  return createHash("sha256").update(text, "utf8").digest("hex");
+}
+
 describe("ssh windows PowerShell safety prelude", () => {
   test("shadows ConvertTo-Json and strips filesystem ETS metadata", () => {
     const prelude = windowsPowerShellScriptPrelude("C:\\test");
@@ -59,6 +65,58 @@ describe("ssh windows fs read-only operations", () => {
   });
 });
 
+describe("ssh host apply-patch fs backend", () => {
+  test("uses POSIX bulk fs operations for host routes", async () => {
+    const invocation = parseSshInvocation("D601:/mnt/f/Work/ConStart", ["apply-patch"]);
+    const text = "alpha\nold\nomega\n";
+    const calls: Array<{ operation: string; args: string[]; input?: string }> = [];
+    const fs = createPosixApplyPatchFileSystem(invocation, async (command, input) => {
+      const operation = command[4] ?? "";
+      const args = command.slice(5);
+      calls.push({ operation, args, input });
+      if (operation === "read-bulk-b64") {
+        return {
+          exitCode: 0,
+          stderr: "",
+          stdout: [
+            "UNIDESK_APPLY_PATCH_V2_BULK_READ 1",
+            [
+              Buffer.from("docs/test.md", "utf8").toString("base64"),
+              String(Buffer.byteLength(text, "utf8")),
+              sha256Hex(text),
+              Buffer.from(text, "utf8").toString("base64"),
+            ].join(" "),
+            "",
+          ].join("\n"),
+        };
+      }
+      if (operation === "apply-replacements-bulk-stdin") {
+        expect(input).toContain(Buffer.from("docs/test.md", "utf8").toString("base64"));
+        return { exitCode: 0, stdout: "", stderr: "" };
+      }
+      throw new Error(`unexpected operation ${operation}`);
+    });
+
+    const files = await fs.readFiles!(["docs/test.md"]);
+    await fs.applyReplacementsBulk!(["docs/test.md"], new Map([[
+      "docs/test.md",
+      {
+        path: "docs/test.md",
+        originalBytes: Buffer.byteLength(text, "utf8"),
+        originalSha256: sha256Hex(text),
+        finalBytes: Buffer.byteLength("alpha\nnew\nomega\n", "utf8"),
+        finalSha256: sha256Hex("alpha\nnew\nomega\n"),
+        replacements: [[1, 1, ["new"]]],
+      },
+    ]]));
+
+    expect(files.get("docs/test.md")).toBe(text);
+    expect(calls.map((call) => call.operation)).toEqual(["read-bulk-b64", "apply-replacements-bulk-stdin"]);
+    expect(calls[0]?.args).toEqual(["docs/test.md"]);
+    expect(calls[1]?.args).toEqual(["1"]);
+  });
+});
+
 describe("ssh stdout bounded streaming", () => {
   test("uses bounded defaults and clamps env override", () => {
     expect(sshStdoutStreamMaxBytes({} as NodeJS.ProcessEnv)).toBe(256 * 1024);