HttpClient.followRedirects is misleading

[tmcw]

What version of Effect is running?

3.21.0

What steps can reproduce the bug?

Effect provides a method HttpClient.followRedirects() that appears to configure whether the client should follow a number of redirects. But FetchHttpClient has no RequestInit options, so it automatically follows redirects, making followRedirects a noop.

What is the expected behavior?

It's hard to tell what the expected behavior is because the FetchHttpClient has no documentation, but ideally it would not be possible to write this kind of misleading code.

What do you see instead?

Redirect following would be detected in the client provided, or controlled from the option per-request.

Additional information

No response

[truffle-dev]

The mechanism, verified at HEAD:

• HttpClient.followRedirects (public, HttpClient.ts:627-630) wraps internal.followRedirects.
• The internal loop (internal/httpClient.ts:906-944) re-issues only when response.status >= 300 && response.status < 400 && response.headers.location. It terminates on the first response otherwise.
• FetchHttpClient constructs RequestInit without a redirect field (internal/fetchHttpClient.ts:13-51). globalThis.fetch defaults to redirect: 'follow', so the underlying fetch transparently follows 3xx and returns the terminal response. The loop's predicate can never fire.

Three fix shapes, increasing in cost:

1. JSDoc the limitation on followRedirects: note that it only applies to clients which surface 3xx responses, and name FetchHttpClient as one that doesn't.
2. Accept redirect on the existing requestInitTagKey FiberRef, so callers can opt into redirect: 'manual' themselves and the decorator works. Smallest user-facing change, no breaking call sites, leverages the existing options pathway.
3. Have followRedirects set redirect: 'manual' automatically when composed onto FetchHttpClient. Most discoverable, but introduces client-type knowledge in a decorator that's meant to be client-generic.

Shape (2) reads cleanest. It keeps the decorator generic and gives the caller one path that's easy to document. Happy to draft the PR if that direction sounds right.

[mvanhorn]

Implemented in #6235 - added maxRedirects parameter, unified default to follow-up-to-10 across platforms, and documented the JSDoc.