fix: parse_response crashes on null output from Codex backend stream

[thiagobarbosa]

Fix #3313

Fix a crash in parse_response when a Response from the Codex backend stream has a null (None) output field instead of a list.

Before this fix, any consumer receiving a Response with a null output (observed from the Codex backend stream) would hit a TypeError: 'NoneType' object is not iterable inside parse_response. The fix treats a missing/None output the same as an empty list, matching how other optional list fields are typically handled in this SDK.

• src/openai/lib/_parsing/_responses.py: iterate over response.output or [] instead of response.output, so a None output no longer raises a TypeError and is treated as an empty output list. This file lives under src/openai/lib/, which per CONTRIBUTING.md is excluded from code generation, so it's safe to edit by hand.
• tests/lib/responses/test_responses.py: add test_parse_response_handles_null_output, which constructs a Response with output=None and asserts parse_response(...) returns parsed.output == [] instead of raising.

[Copilot]

Pull request overview

Fixes a TypeError in parse_response() when the Codex backend stream returns a Response with output: null by treating None output as an empty list, and adds regression test coverage for that case.

Changes:

• Guard parse_response() against response.output is None by iterating over response.output or [].
• Add a unit test asserting output=None is parsed as [] without raising.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/openai/lib/_parsing/_responses.py	Prevents iteration over None by defaulting missing/None output to an empty list.
tests/lib/responses/test_responses.py	Adds a regression test to ensure parse_response() handles output=None and returns parsed.output == [].

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[chatgpt-codex-connector]

Preserve accumulated stream output on null completion

When this parser is used from the streaming path, response.completed is parsed from event.response while the actual output items have already been accumulated on the stream snapshot. If the backend sends output: null on the completion event after normal response.output_item.*/delta events, this fallback now returns a successful parsed response with output == []; get_final_response() and the wrapped completed event then lose all generated content instead of returning the accumulated response. Please have the stream completion path reuse the snapshot output when the completed response output is None.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.