Support Guzzle 8: regenerate with fern-php-sdk 2.x

[crocodele]

intercom/intercom-php requires guzzlehttp/guzzle: ^7.4, which blocks projects from upgrading to Guzzle 8 (released August 2026). Widening the constraint isn't enough on its own: the generated code relies on Guzzle 7 behavior that changed in Guzzle 8 (e.g. RequestException::getResponse() no longer exists; network errors that aren't connect failures are no longer ConnectException, so the retry middleware would stop retrying them).

fernapi/fern-php-sdk 2.0.0+ generates PSR-18-agnostic code (fern-api/fern#12151): Guzzle becomes a dev dependency only, and any PSR-18 client works through php-http/discovery. That removes the Guzzle constraint entirely. The change would be bumping php-sdk in Intercom-OpenAPI fern/generators.yml from 1.25.0 to 2.x.

Proof of concept: crocodele/intercom-php@fern-php-sdk-2x (a PR isn't possible since PRs are limited to collaborators).

How this was generated

• Spec: intercom/Intercom-OpenAPI@184e88b754, the spec behind the last regeneration (🌿 Fern Regeneration -- January 30, 2026 #397), so the diff reflects only the generator change.
• fern CLI 5.138.1 + fernapi/fern-php-sdk 2.23.0 (2.x needs CLI ≥ 5.44.6).
• Sanity check: CLI 3.0.2 + 1.25.0 on the same spec reproduces current master (apart from version headers).
• composer.json (in .fernignore) updated by hand:
  • Generated requirements: psr/http-client(-implementation), psr/http-factory(-implementation), php-http/discovery, php-http/multipart-stream-builder.
  • Kept for src/Legacy: php-http/client-common, php-http/message, nyholm/psr7.
  • guzzlehttp/guzzle moved to require-dev as ^7.4 || ^8.0.
• README.md kept from master, because local generation doesn't produce the Legacy SDK section.

Known generator bug (worked around here)

2.x generates createMessage(mixed|null $request = null, ...) in Unstable\Messages\MessagesClient. PHP 8.0+ rejects that, so the class fatals on load. The second commit on the branch hand-fixes it to mixed. The upstream fix is fern-api/fern#17893; once released, regenerating won't need this commit.

Verification

• composer test: 95 tests, 341 assertions, passing with Guzzle 8.2.0 (psr7 3.1, promises 3.0) and Guzzle 7.15.5.
• All 1,083 classes under src/ load.
• Smoke test with a Guzzle MockHandler, on both Guzzle 7 and 8:
  • Endpoint call deserializes correctly.
  • 404 → IntercomApiException.
  • Network error → IntercomException.
  • 503 is retried.
  • Default client discovery works.
  • The Legacy client works.
• composer analyze (phpstan): the only errors are in test files. 3 exist on master already; 2 come from the generated RawClientTest.

Breaking changes for SDK users (would warrant 6.0)

• Guzzle isn't installed automatically anymore, and a custom client option must be a PSR-18 client.
• Core\Client\RetryMiddleware is removed; retries now use RetryDecoratingClient.
• Per-request timeout only works with Guzzle or Symfony HttpClient.
• JSON-returning endpoint methods now return nullable types (T → ?T, 247 methods); an empty response body returns null instead of throwing (fix(php): Return null for empty JSON responses instead of throwing fern-api/fern#14027).
• Some request/type classes were renamed by the newer CLI, e.g. ReplyConversationRequest → ReplyConversationBody, UpdateArticleRequestState → UpdateArticleRequestBodyState.

🤖 Generated with Claude Code