[danieljbruce]

Description

Replaces proxyquire with sinon and direct stubs across four packages.

Impact

Removes --proxyquire-shim from gax, googleapis-common, error-reporting, and translate unit tests.

Changes

• Part 1 of 5 in stacked PR series: test: replace proxyquire with sinon in gax, common, error-reporting, translate #9638 -> test: remove --proxyquire-shim from common, bigquery, datastore, and dns #9639 -> test: remove --proxyquire-shim from logging and pubsub packages #9640 -> test: remove --proxyquire-shim from bigtable, spanner, and storage #9641 -> chore: remove proxyquire-bun-shim.cjs and runner flags #9633 (b/570680750).
• core/packages/gax: Replace proxyquire in test/unit/grpc.ts with sinon.stub(fs, 'existsSync') and remove --proxyquire-shim from package.json.
• core/packages/nodejs-googleapis-common: Replace proxyquire in test/test.authplus.ts and test/test.http2.ts with sinon.stub(auth.GoogleAuth.prototype, 'getClient') and sinon.stub(coreHttp2, 'connect'), and remove --proxyquire-shim from package.json.
• handwritten/error-reporting: Stub util.makeAuthenticatedRequestFactory and RequestHandler.prototype.request directly in test/unit/google-apis/auth-client.ts and remove --proxyquire-shim from package.json.
• packages/google-cloud-translate: Intercept Module.prototype.require directly in test/index.ts before() hook and remove --proxyquire-shim from package.json.

Testing

• Executed pnpm test under both Node.js and Bun (JS_RUNTIME=bun) in core/packages/gax, core/packages/nodejs-googleapis-common, handwritten/error-reporting, and packages/google-cloud-translate.
• Verified strict lint and type checks pass via bin/linter.mjs --strict.

Alternatives

• Not merging this pull request was considered, which would leave these four packages dependent on the global bin/proxyquire-bun-shim.cjs preload shim.

[gemini-code-assist]

Code Review

This pull request removes the dependency on proxyquire across multiple packages, replacing it with standard sinon stubs and manual module caching techniques for mocking, which also allows removing the --proxyquire-shim flag from test scripts. The review feedback suggests two key improvements: first, avoid overriding Module.prototype.require in the Translate tests by directly mutating the cached module exports instead; second, stub the getClient method on the specific auth instance rather than on the GoogleAuth prototype to prevent global prototype pollution.

[gemini-code-assist]

Overriding Module.prototype.require is a fragile hack that relies on Node.js internal APIs and can easily break across different Node versions or alternative runtimes (like Bun or Deno). Since @google-cloud/common and @google-cloud/promisify are already loaded and cached in require.cache, you can simply mutate their exported properties on the cached module objects before requiring ../src/v2, and restore them in the finally block. This is much cleaner, safer, and standard.

    const common = require('@google-cloud/common');
    const origUtil = common.util;
    const origService = common.Service;
    const origPromisifyAll = pfy.promisifyAll;

    common.util = fakeUtil;
    common.Service = FakeService;
    pfy.promisifyAll = fakePromisify;

    const v2Path = require.resolve('../src/v2');
    const cached = require.cache[v2Path];
    delete require.cache[v2Path];
    try {
      Translate = require('../src/v2').Translate;
    } finally {
      common.util = origUtil;
      common.Service = origService;
      pfy.promisifyAll = origPromisifyAll;
      if (cached) require.cache[v2Path] = cached;
    }

[gemini-code-assist]

Instead of stubbing the prototype of GoogleAuth (which mutates the class prototype globally for all instances), you can stub the getClient method directly on the auth instance. This is safer, avoids prototype pollution, and is more idiomatic.

Suggested change

	const getClientStub = sinon
	.stub(auth.GoogleAuth.prototype, 'getClient')
	// eslint-disable-next-line @typescript-eslint/no-explicit-any
	.resolves({} as any);
	const getClientStub = sinon
	.stub(auth, 'getClient')
	// eslint-disable-next-line @typescript-eslint/no-explicit-any
	.resolves({} as any);