Bug: efc-dead-code-and-latent-nre-traps #466

• Work Mode: full-bug

Summary

EfcViewer.SetController is never called, so EfcViewer._formController is permanently null and
EditFiltersMenuItem_Click carries a latent NullReferenceException that a routine Designer
regeneration would arm. Several other EFC members and one orphaned file are dead code.

Environment

• OS/version: Windows 11 Pro 10.0.26200
• Runtime: .NET Framework 4.8.1 WinForms VSTO add-in
• UI path: QuickFiler/Viewers/EfcViewer.cs, QuickFiler/Controllers/EfcItemController.cs
• Data source or fixture: n/a

Steps to Reproduce

The trap is currently unreachable by design; it is armed by a maintenance action:

1. Open EfcViewer in the Visual Studio Designer and re-generate EfcViewer.Designer.cs, or otherwise
   wire EditFiltersMenuItem.Click to EfcViewer.EditFiltersMenuItem_Click.
2. Open the Email Filer viewer and choose the Edit Filters menu item.
3. Observe NullReferenceException.

Expected Behavior

Either the controller is wired into the viewer so the Edit Filters command works, or the dead member
and its unreachable handler are removed so no trap remains.

Actual Behavior

A - dead SetController, permanently null field. EfcViewer.cs:50-53 declares
internal void SetController(EfcFormController controller). A repository-wide search for
SetController finds call sites only in QfcFormController.cs:44, QfcFormViewer.cs:46,
QfcFormViewerDark.cs:31, QfcFormViewerExpanded.cs:31, and the non-compiled Legacy/ and
EfcViewer3.cs files. EfcFormController never calls it, unlike its QFC twin. Consequently
EfcViewer._formController (EfcViewer.cs:48) is always null and
EfcViewer.EditFiltersMenuItem_Click (EfcViewer.cs:157-160) would throw.

The handler is currently unreachable: EfcViewer.Designer.cs never wires EditFiltersMenuItem.Click.
Verified - across 4,277 lines the only references are the declaration at :67, the DropDownItems
add at :4123, three property assignments at :4136-4138, and the field at :4275. There is no
+= at all. So this is dead code carrying a latent trap, not a live crash.

B - zero-call-site members in EfcItemController. InitializeWebView() (:174-205) and
RegisterActions(...) (:680-692) have no call sites repo-wide (verified by grep across QuickFiler/
and QuickFiler.Test/). _selectorsCtrls (:381) is initialized to null and never assigned before
being passed to SetupThemes as the selectors argument (:97, :144).

C - unused constructor overload. The EfcItemController
(globals, homeController, parent, itemViewer, dataModel, bool async, token) overload (:44-57) has
zero call sites; only the 6-argument (:30) and 5-argument (:59) forms are used, by
EfcFormController.cs:87 and :69.

D - orphaned uncompiled files. QuickFiler/Viewers/EfcViewer3.cs and its siblings are present in
the working tree but carry no <Compile Include> entry in QuickFiler/QuickFiler.csproj. EfcViewer3.cs
nonetheless carries an [ExcludeFromCodeCoverage] attribute at :17, which is misleading - an
uncompiled file needs no exemption.

Logs / Screenshots

• Attached minimal logs or screenshot
• Code-read evidence recorded above (verified 2026-08-07 against the working tree).

Impact / Severity

• Blocker
• High
• Medium
• Low

Nothing fails today. The severity is the maintenance trap: the Edit Filters command is silently
non-functional, and the natural act of re-wiring it in the Designer converts that into a crash.

Source

From: docs/features/potential/2026-08-07-efc-dead-code-and-latent-nre-traps.md