Fixes #454

Summary

When creating or updating a draft with attachments larger than 3MB (which triggers multipart/form-data upload), the SDK throws a TypeError: tuple indices must be integers or slices, not str.

Root Cause

_http_client._execute() returns a tuple (json_response, headers) (via _validate_response in http_client.py line 48). However, the multipart code paths in drafts.create() and drafts.update() assigned the entire tuple to a single variable instead of unpacking it:

# Before (broken) — json_response is actually (dict, headers) tuple
json_response = self._http_client._execute(...)
return Response.from_dict(json_response, Draft)  # TypeError

The send() method already did this correctly:

# send() — correct pattern
json_response, headers = self._http_client._execute(...)
return Response.from_dict(json_response, Message, headers)

Fix

Applied the same tuple-unpacking pattern to both create() and update() multipart code paths in nylas/resources/drafts.py:

create():

json_response, headers = self._http_client._execute(
    method="POST",
    path=path,
    data=_build_form_request(request_body),
    overrides=overrides,
)
return Response.from_dict(json_response, Draft, headers)

update():

json_response, headers = self._http_client._execute(
    method="PUT",
    path=path,
    data=_build_form_request(request_body),
    overrides=overrides,
)
return Response.from_dict(json_response, Draft, headers)

Changes

• nylas/resources/drafts.py — 4 lines changed (2 in create(), 2 in update())
• CHANGELOG.md — entry added under Unreleased
• tests/resources/test_drafts.py — 2 regression tests added (see below)

Testing

Regression tests (added in this PR)

Two new tests in tests/resources/test_drafts.py exercise the real Response.from_dict code path (no patch on Response) with _execute returning a realistic (dict, headers) tuple, then assert the call returns a Response[Draft] with the expected data, request_id, and headers:

• test_create_draft_large_attachment_unpacks_execute_tuple
• test_update_draft_large_attachment_unpacks_execute_tuple

I verified that reverting the fix in nylas/resources/drafts.py causes both new tests to fail with the exact TypeError: tuple indices must be integers or slices, not str from issue #454, confirming they regression-cover the bug. Reapplying the fix → both pass.

The pre-existing test_create_draft_with_special_characters_large_attachment did not catch this bug because it patched Response.from_dict and only asserted on _execute call args, not on processing of the return value.

Full suite

============== 449 passed, 3 deselected, 1 warning in 1.66s ==============

Manual verification against Nylas sandbox

Earlier verified end-to-end against a real Microsoft (Outlook) grant by creating and sending a draft with a real 7MB PDF attachment via drafts.create() (and via the create → send flow). Both succeeded without TypeError, confirming the fix works on the wire.

I confirm that this contribution is made under the terms of the MIT license and that I have the authority necessary to make this contribution on behalf of its copyright owner.