rea/tests/process-global/filesystemSnapshotFallbackCancellation.test.ts

import { createHash } from "node:crypto";
import { lstat, writeFile } from "node:fs/promises";
import type { FileHandle } from "node:fs/promises";
import { join } from "node:path";

import { afterEach, expect, it, vi } from "vitest";

const observation = vi.hoisted(() => ({
  path: "",
  namedReads: 0,
  cancelAt: 0,
  controller: undefined as AbortController | undefined,
  reason: undefined as Error | undefined,
  handles: [] as FileHandle[],
}));

// Force the capability fallback while keeping actual filesystem IO. These
// cases establish cancellation semantics, not native Windows compatibility.
vi.mock("node:fs", async (importOriginal) => {
  const original = await importOriginal<typeof import("node:fs")>();
  return {
    ...original,
    constants: { ...original.constants, O_NOFOLLOW: 0 },
  };
});

vi.mock("node:fs/promises", async (importOriginal) => {
  const original = await importOriginal<typeof import("node:fs/promises")>();
  return {
    ...original,
    open: async (...args: Parameters<typeof original.open>) => {
      const handle = await original.open(...args);
      if (args[0] === observation.path) observation.handles.push(handle);
      return handle;
    },
    lstat: async (...args: Parameters<typeof original.lstat>) => {
      const stats = await original.lstat(...args);
      if (
        args[0] === observation.path &&
        ++observation.namedReads === observation.cancelAt
      )
        observation.controller?.abort(observation.reason);
      return stats;
    },
  };
});

import { parseProcessScenario } from "../../src/domain/process/processScenario.js";
import {
  hashFile,
  snapshotRoots,
} from "../../src/process/capture/FilesystemSnapshot.js";
import { createTestTempDirectory } from "../fixtures/temporaryDirectory.js";

afterEach(() => {
  observation.path = "";
  observation.namedReads = 0;
  observation.cancelAt = 0;
  observation.controller = undefined;
  observation.reason = undefined;
  observation.handles.length = 0;
});

it.each(["hash", "snapshot"] as const)(
  "rejects cancellation during the final %s fallback inspection and closes the descriptor",
  async (operation) => {
    const directory = await createTestTempDirectory("rea-fs-fallback-cancel-");
    const path = join(directory, "observed-file");
    await writeFile(path, "captured bytes");
    const expected = await lstat(path);
    const controller = new AbortController();
    const reason = Object.assign(
      new Error("cancelled during final named-file inspection"),
      { code: "EACCES" },
    );
    observation.path = path;
    observation.controller = controller;
    observation.reason = reason;
    // A root file snapshot first inspects presence and entry metadata, then
    // reaches the same two named-file inspections as direct hashing.
    observation.cancelAt = operation === "hash" ? 2 : 4;
    const result =
      operation === "hash"
        ? hashFile(path, expected, 1_000, controller.signal)
        : snapshotRoots(
            parseProcessScenario({
              executable: process.execPath,
              working_directory: directory,
              filesystem_observation_paths: [path],
            }),
            controller.signal,
          );
    await expect(result).rejects.toBe(reason);
    expect(controller.signal.aborted).toBe(true);
    expect(observation.handles).toHaveLength(1);
    await expect(observation.handles[0]?.stat()).rejects.toMatchObject({
      code: "EBADF",
    });
  },
);

it("keeps an unchanged fallback digest and closes its descriptor", async () => {
  const directory = await createTestTempDirectory("rea-fs-fallback-digest-");
  const path = join(directory, "observed-file");
  const bytes = Buffer.from("captured bytes");
  await writeFile(path, bytes);
  const expected = await lstat(path);
  observation.path = path;
  await expect(hashFile(path, expected, 1_000)).resolves.toEqual({
    state: "hashed",
    sha256: createHash("sha256").update(bytes).digest("hex"),
  });
  expect(observation.namedReads).toBe(2);
  expect(observation.handles).toHaveLength(1);
  await expect(observation.handles[0]?.stat()).rejects.toMatchObject({
    code: "EBADF",
  });
});