fix(pi-ssh): harden remote execution and search

pi-ssh/test/remote-probe.test.ts

@@ -0,0 +1,57 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+import { parseRemotePathProbe, probeRemotePath } from "../src/remote-probe.ts";
+import type { RemoteExecOptions, RemoteTransport } from "../src/ssh2-transport.ts";
+
+class ProbeTransport implements RemoteTransport {
+  command = "";
+  cwd = "";
+  connect(): Promise<void> { return Promise.resolve(); }
+  dispose(): Promise<void> { return Promise.resolve(); }
+  exec(command: string, cwd: string, options: RemoteExecOptions): Promise<{ exitCode: number | null }> {
+    this.command = command;
+    this.cwd = cwd;
+    const start = command.match(/'(__PI_SSH_PROBE_[a-f0-9]+_START__)'/)?.[1];
+    const end = command.match(/'(__PI_SSH_PROBE_[a-f0-9]+_END__)'/)?.[1];
+    if (!start || !end) throw new Error("probe markers missing");
+    options.onData(Buffer.from(`login banner\n${start}/srv/project${end}\nlogout banner\n`));
+    return Promise.resolve({ exitCode: 0 });
+  }
+  capture(): Promise<{ exitCode: number | null; output: Buffer }> { throw new Error("not used"); }
+  readFile(): Promise<Buffer> { throw new Error("not used"); }
+  ensureReadable(): Promise<void> { throw new Error("not used"); }
+  ensureReadableWritable(): Promise<void> { throw new Error("not used"); }
+  detectImageMimeType(): Promise<string | null> { throw new Error("not used"); }
+  mkdir(): Promise<void> { throw new Error("not used"); }
+  writeFile(): Promise<void> { throw new Error("not used"); }
+}
+
+test("extracts one framed absolute path while ignoring shell startup output", async () => {
+  const transport = new ProbeTransport();
+  assert.equal(await probeRemotePath(transport, "cwd", "/srv"), "/srv/project");
+  assert.equal(transport.cwd, "/srv");
+  assert.match(transport.command, /pwd -P/);
+});
+
+test("rejects unframed, relative, multiline, and oversized path probes", () => {
+  assert.throws(() => parseRemotePathProbe(Buffer.from("/srv"), "START", "END", "cwd"), /invalid framed/);
+  assert.throws(() => parseRemotePathProbe(Buffer.from("STARTrelativeEND"), "START", "END", "cwd"), /absolute POSIX path/);
+  assert.throws(() => parseRemotePathProbe(Buffer.from("START/srv\notherEND"), "START", "END", "cwd"), /absolute POSIX path/);
+  assert.throws(
+    () => parseRemotePathProbe(Buffer.alloc(64 * 1024 + 1), "START", "END", "cwd"),
+    /exceeded 65536 bytes/,
+  );
+});
+
+test("forwards cancellation to the probe exec call", async () => {
+  const controller = new AbortController();
+  controller.abort();
+  const transport = new ProbeTransport();
+  const original = transport.exec.bind(transport);
+  transport.exec = (command, cwd, options) => {
+    assert.equal(options.signal, controller.signal);
+    if (options.signal?.aborted) return Promise.reject(new Error("SSH command aborted"));
+    return original(command, cwd, options);
+  };
+  await assert.rejects(probeRemotePath(transport, "home", ".", controller.signal), /SSH command aborted/);
+});