PPF-2059: Skip an empty rename commit during full-name merges #2059

Version

Reviewed baseline: PyPDFForm 6.0.0, commit 0b5cc1dc8604b36693864852d76ed7e60f903451.

Issue Description

At the reviewed snapshot, merging full-name wrappers containing distinct left and right fields raised NotImplementedError. __add__() unconditionally called other.commit_widget_key_updates(), even with no queued renames. Page slices that merge wrappers can encounter the same failure.

Work

In wrapper.py, avoid the unsupported full-name rename path when no rename is queued. Preserve the explicit limitation for an actual unsupported rename rather than suppressing all errors.

Acceptance Criteria

• Full-name wrappers containing distinct left and right fields merge successfully; true collisions still follow an explicit existing or documented limitation. Exercise page slices that rely on merging as well.

Basis and Dependencies

R09. Does not require choosing a new collision policy; E4-02 addresses broader identity and operand behavior.

Source and Validation

Action E1-06, Group 1 — Lowest-hanging fruit, from the October 10, 2026 action plan; supporting review evidence. Related action identifiers refer to that plan.

The behavior above is evidence from the source review, not a new reproduction performed when filing this issue. Reconfirm the relevant baseline or document intervening changes before implementation. Follow the plan's completion and validation rules and the Developer Guide, including meaningful regression assertions for behavior changes.