Preserve array separators when appending after standalone comments

[vera-rubin]

Summary

On tomlkit 0.15.1 (19edc23b0244), appending produces a = [1\n# end\n2\n]\n. TOML requires commas; expected parsed output is {"a": [1, 2]}.

import tomlkit

doc = tomlkit.parse("a = [1\n# end\n]\n")
doc["a"].append(2)
print(tomlkit.dumps(doc), end="")

We now look past standalone comments for the preceding value or separator, preserving indentation and trailing comma style.

We tested the regression cases and the full existing suite, and checked the saved document with tomllib.

Agent Drafting Metadata

AI-assisted.

• Agent: Codex
• Model: gpt-6.1-sol
• Notes: AI-assisted: yes, reviewed and tested as described.

Assisted-by: Codex / gpt-6.1-sol

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