Summary

Fixes a Node HTTP adapter regression where custom httpsAgent TLS options were not applied to the tunneled HTTPS origin after CONNECT proxy setup.

Linked issue

Closes #10953

Changes

• Merge user httpsAgent.options into the HttpsProxyAgent callback options used for the post-CONNECT TLS upgrade.
• Add an HTTP CONNECT proxy regression test with a self-signed HTTPS origin trusted via httpsAgent.ca.
• Record the bug fix in the pre-release changelog.

Checklist

• Tests added or updated (or N/A with reason)
• Docs / types updated if public API changed (index.d.ts and index.d.cts)
• No breaking changes (or called out explicitly above)

Summary by cubic

Fixes a Node HTTP adapter regression that dropped httpsAgent TLS options (e.g., ca, rejectUnauthorized) when connecting to an HTTPS origin through a CONNECT proxy. Restores expected TLS behavior for tunneled requests.

Description

• Summary of changes
  • Merge user httpsAgent.options into HttpsProxyAgent constructor and its callback so post-CONNECT TLS uses the same options.
  • Add an integration test for CONNECT → HTTPS with a self-signed origin trusted via httpsAgent.ca.
  • Add a pre-release changelog entry.
• Reasoning
  • Without forwarding these options, tunneled HTTPS requests could not trust custom CAs or honor rejectUnauthorized, causing failures.
• Additional context
  • Addresses issue Problem handling self signed cert for proxy in 1.16.1 #10953.

Docs

• Propose a brief note in /docs/ explaining that httpsAgent TLS options are honored for HTTPS origins behind HTTP CONNECT proxies, with an example showing proxy + httpsAgent (custom ca, rejectUnauthorized).

Testing

• Added an integration test that sets up:
  • An HTTP proxy handling CONNECT.
  • An HTTPS origin with a self-signed cert.
  • A request using httpsAgent.ca to trust the origin and verify payload and plaintext is not leaked.
• Updated a unit test name to reflect constructor-option merging. No other test changes required.

Semantic version impact

• Patch: bug fix with no API changes.

^{Written for commit 1b359a8. Summary will update on new commits.}

Review in cubic