XCEngine/docs/used/NewEditor_TreeActualRedundancyReductionPlan_2026-04-22.md

NewEditor Tree Actual Redundancy Reduction Plan

Date: 2026-04-22 Status: In Progress

Goal

• Remove only the redundancy that is structurally real in new_editor tree-related code.
• Keep the existing panel refresh split, frame ownership, and hosted-panel dispatch architecture intact.
• Accept only changes that produce clear net code reduction and keep ownership clearer, not blurrier.

Why The Previous Plan Was Deleted

• The deleted plan incorrectly treated the rename flow as a shared tree host skeleton.
• HierarchyPanel is a single-tree, single-surface rename owner.
• ProjectPanel is a tree/grid dual-surface rename owner and its rename bounds, state, and commit side-effects differ materially.
• Because of that difference, extracting rename state handling upward adds request/status/surface glue instead of deleting real code.
• Any cross-panel rename abstraction is now considered a wrong direction for this codebase.

Hard Constraints

• HierarchyPanel / ProjectPanel rename flow is explicitly not a dedup target.
• Do not merge panel refresh loops.
• Do not merge project tree and asset grid behavior.
• Do not change viewport independent request/render flow.
• Do not change EditorWindowFrameDriver single frame owner semantics.
• Do not move project or scene runtime semantics into XCEditor.
• Do not create new Behavior, Host, Helper, Support, Tooling, or similar glue files.
• Any phase must have a credible negative net diff before implementation starts.

Real Remaining Redundancy Targets

1. ProjectPanel Left-Tree Internal Repetition

This is the first valid target.

Current repetition shape:

• repeated left-tree layout rebuild sequences after navigation / drop / refresh paths
• repeated left-tree draw call setup for background / foreground / rename overlay / drop preview
• repeated left-tree state sync and cleanup around operations inside the same panel

Rules:

• Keep this work inside ProjectPanel and existing tree modules.
• Prefer local private functions or same-file narrowing over new files.
• Do not generalize tree/grid business logic together.

2. Cross-Panel Tree Draw Chain Re-Audit

This is only a candidate target, not an automatic extraction target.

Possible shared shape:

• append tree background
• append tree foreground
• append inline rename overlay
• append drop preview

Rules:

• Only extract if the result is a pure UI draw chain with no business ownership leakage.
• Only extract into existing UIEditorTreeView.* if total code clearly goes down.
• If the net diff is not negative, stop and keep the code local.

3. Final Intentional-Duplication Audit

After the valid reductions above, re-check what remains.

Expected intentional duplicates:

• rename ownership between HierarchyPanel and ProjectPanel
• scene-specific drag/drop commit behavior
• project-specific folder / asset / breadcrumb / splitter / context menu orchestration

If a remaining overlap is only superficial orchestration around different business surfaces, record it as intentional and stop.

Execution Plan

Phase A. Freeze The Rename Boundary

Status: Completed

Target:

• Remove the invalid rename-dedup direction from the active plan baseline.

Completed result:

• Deleted the wrong plan that targeted cross-panel rename host dedup.
• Re-established rename as panel-owned business logic, not a shared tree abstraction target.

Validation:

• Documentation baseline corrected.

Phase B. Reduce ProjectPanel Left-Tree Internal Repetition

Status: Completed

Target:

• Shrink repeated left-tree orchestration inside ProjectPanel without changing behavior boundaries.

Allowed scope:

• new_editor/app/Features/Project/ProjectPanel.cpp
• new_editor/app/Features/Project/ProjectPanel.h

Rules:

• No new file.
• No tree/grid semantic merge.
• No rename abstraction promotion.
• Only keep helpers that delete more code than they add.

Validation:

• cmake --build build --config Debug --target XCUIEditorApp
• smoke-launch build/new_editor/Debug/XCUIEditor.exe
• confirm latest runtime.log contains:
  • EnsureEditorStartupScene loaded scene=Main Scene
  • [app] initialize end
  • [app] shutdown end

Completed result:

• Reduced the real repeated reconcile chain inside ProjectPanel.
• Kept tree/grid business ownership split intact.
• Landed local private narrowing only:
  • runtime-to-UI selection sync now funnels through one panel-local path
  • layout/tree-frame rebuild now funnels through one panel-local path
• ProjectBrowserModel also now owns a single browser-state refresh chain instead of repeating:
  • RefreshFolderTree()
  • EnsureValidCurrentFolder()
  • RefreshAssetList()

Phase C. Re-Audit The Shared Tree Draw Chain

Status: Pending

Target:

• Check whether a narrow draw-chain entry in existing UIEditorTreeView.* can reduce real code across HierarchyPanel and the Project left tree.

Allowed scope:

• new_editor/include/XCEditor/Collections/UIEditorTreeView.h
• new_editor/src/Collections/UIEditorTreeView.cpp
• the two panel files only where call sites get smaller

Rules:

• No state machine extraction.
• No rename surface abstraction.
• No drag/drop business extraction.
• Cancel the phase immediately if the predicted diff is not net-negative.

Validation:

• rg verification of targeted duplicate draw blocks
• cmake --build build --config Debug --target XCUIEditorApp
• smoke-launch build/new_editor/Debug/XCUIEditor.exe

Phase D. Final Closure Audit

Status: Pending

Target:

• Verify that all remaining overlap is either reduced or explicitly intentional.

Validation:

• targeted rg audit
• git diff --stat confirms accepted phases reduced code overall
• cmake --build build --config Debug --target XCUIEditorApp
• smoke-launch build/new_editor/Debug/XCUIEditor.exe

Acceptance

• The wrong rename-dedup plan no longer exists in docs/plan.
• Cross-panel rename dedup is explicitly excluded.
• The next implementation target is ProjectPanel left-tree internal repetition, not rename.
• No new glue-layer file is introduced.
• Each accepted phase must reduce code, not grow it.
• Build and smoke validation pass after each completed implementation phase.