refactor(security): dedupe shell env probe and add path regression test

src/agents/bash-tools.exec.path.test.ts

@@ -1,3 +1,6 @@
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 import type { ExecApprovalsResolved } from "../infra/exec-approvals.js";
 import { captureEnv } from "../test-utils/env.js";
@@ -67,7 +70,7 @@ describe("exec PATH login shell merge", () => {
   let envSnapshot: ReturnType<typeof captureEnv>;
 
   beforeEach(() => {
-    envSnapshot = captureEnv(["PATH"]);
+    envSnapshot = captureEnv(["PATH", "SHELL"]);
   });
 
   afterEach(() => {
@@ -112,6 +115,43 @@ describe("exec PATH login shell merge", () => {
 
     expect(shellPathMock).not.toHaveBeenCalled();
   });
+
+  it("does not apply login-shell PATH when probe rejects unregistered absolute SHELL", async () => {
+    if (isWin) {
+      return;
+    }
+    process.env.PATH = "/usr/bin";
+    const shellDir = fs.mkdtempSync(path.join(os.tmpdir(), "openclaw-shell-env-"));
+    const unregisteredShellPath = path.join(shellDir, "unregistered-shell");
+    fs.writeFileSync(unregisteredShellPath, '#!/bin/sh\nexec /bin/sh "$@"\n', {
+      encoding: "utf8",
+      mode: 0o755,
+    });
+    process.env.SHELL = unregisteredShellPath;
+
+    try {
+      const shellPathMock = vi.mocked(getShellPathFromLoginShell);
+      shellPathMock.mockClear();
+      shellPathMock.mockImplementation((opts) =>
+        opts.env.SHELL?.trim() === unregisteredShellPath ? null : "/custom/bin:/opt/bin",
+      );
+
+      const tool = createExecTool({ host: "gateway", security: "full", ask: "off" });
+      const result = await tool.execute("call1", { command: "echo $PATH" });
+      const entries = normalizePathEntries(result.content.find((c) => c.type === "text")?.text);
+
+      expect(entries).toEqual(["/usr/bin"]);
+      expect(shellPathMock).toHaveBeenCalledTimes(1);
+      expect(shellPathMock).toHaveBeenCalledWith(
+        expect.objectContaining({
+          env: process.env,
+          timeoutMs: 1234,
+        }),
+      );
+    } finally {
+      fs.rmSync(shellDir, { recursive: true, force: true });
+    }
+  });
 });
 
 describe("exec host env validation", () => {