🔧 fix undici erroneously grabing previous request Agents by default

[sebastianMindee]

Description

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Requires a change to the official Guide documentation.

[Copilot]

Pull request overview

This PR addresses a dispatcher-resolution bug where the SDK could accidentally reuse a foreign undici global dispatcher (e.g., the one registered by Node’s built-in fetch), leading to transport-level failures. It adds logic to only reuse the global dispatcher when it was created by the same undici copy as the SDK, otherwise falling back to a library-owned Agent.

Changes:

• Add resolveDefaultDispatcher() in BaseSettings to ignore foreign global dispatchers and use a shared fallback Agent.
• Add unit tests validating dispatcher selection behavior (explicit, same-copy global, foreign global, and fallback reuse).
• Add an integration test that reproduces the failure when explicitly passing a foreign dispatcher and verifies the default client succeeds.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
tests/v2/client/foreignDispatcher.integration.ts	New integration test covering foreign global dispatcher repro + expected fixed behavior.
tests/http/baseSettings.spec.ts	New unit tests for dispatcher resolution logic in BaseSettings.
src/http/baseSettings.ts	Implements foreign-global-dispatcher detection and fallback dispatcher creation.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

Suppressed comments (1)

Previously missed (1) — in code that hasn't changed since the last review.

src/input/urlInput.ts:6

• There’s an extra space after the opening { in the undici import, which is inconsistent with the rest of the codebase and may trip formatting/lint rules.

import {  request, Dispatcher } from "undici";