[liugedragon]

Summary

Date.fromisoformat(), Date.fromordinal() and the other inherited date factories return TOML items with an empty _raw value. Time.fromisoformat() does the same. Serializing one produces value = \n, which both Tomlkit and stdlib tomllib reject.

When no source text was supplied, generate the date's ISO text or use the existing local-time formatter. This follows the fallback already used by DateTime; parsed items retain their original text and comments.

Fifteen regressions cover date/time factories, fractional seconds, existing raw formatting and the unchanged DateTime behavior. On Python 3.11+, serialization is checked with the independent stdlib parser as well as Tomlkit. Before the fix: 11 failed, 4 passed. After the fix: all pass.

Validation on Windows / Python 3.13.4:

• Full suite including the pinned toml-test submodule: 1,449 passed.
• All six configured pre-commit hooks: passed.
• New test file Mypy: passed. Full-tree Mypy reports the same 33 existing diagnostics on both base and patch.

Duplicate Check

• I searched the open PRs and found none that already fixes this issue.
• Related open PRs: Preserve temporal serialization in reflected addition #652 routes reflected addition through the wrappers and preserves trivia; it does not address inherited factories or Time. This change does not replace that trivia fix. tests: stop using parse_rfc3339 as the toml-test datetime oracle #639 changes conformance-test oracles, not factory serialization.

Agent Drafting Metadata

• Agent: OpenAI Codex
• Model: GPT-6 family; the exact variant is not exposed by this session.
• Notes: The implementation and regression tests were agent-authored. The validation commands above were executed locally.

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