nullable(#364): per-file #nullable enable opt-in for UtilitiesCS/HelperClasses

.claude/agent-memory/atomic-executor/MEMORY.md

@@ -1,5 +1,7 @@
 # Atomic Executor Memory Index
 
+- [#364 nullable-gate pre-existing blockers](project_364_nullable_gate_preexisting_blockers.md) — full-solution pragma-only TWAE gate fails at baseline (vendored SVGControl CS0649 + non-HelperClasses CS0618/CS0168); verify CS86xx via isolated UtilitiesCS build w/ BuildProjectReferences=false; analyzer-version drift needs nuget-install into packages/; coverage script single-assembly StrictMode bug
+
 - [Nullable per-file pragma gate mechanics](project_nullable_pragma_gate_mechanics.md) — solution-wide TWAE aborts on vendored SVGControl CS0649; verify via isolated `UtilitiesCS.csproj -t:Rebuild -p:Platform=AnyCPU -p:BuildProjectReferences=false` + grep CS86xx=0
 - [Analyzer version skew on fresh worktree](project_analyzer_version_skew_fresh_worktree.md) — first analyzer build fails CS0006 (Meziantou 3.0.101/Sonar 10.27/BannedApi 3.3.4 missing); nuget install old versions into gitignored packages/, don't edit 16 csproj
 - [Nullable remediation annotation patterns](project_nullable_remediation_annotation_patterns.md) — net481 no post-condition attrs; EmailRecord struct `= default!`; `.ToString()!` for string cells; IsNullOrEmpty overload gotcha; `x!.M()` for defensive-flow-state

.claude/agent-memory/atomic-executor/project_364_nullable_gate_preexisting_blockers.md

@@ -0,0 +1,18 @@
+---
+name: 364-nullable-gate-preexisting-blockers
+description: The full-solution pragma-only nullable gate fails at baseline on the epic-integration branch (vendored SVGControl CS0649 + non-HelperClasses UtilitiesCS CS0618/CS0168); verify CS86xx via isolated UtilitiesCS build. Plus analyzer-version drift and coverage-script single-assembly bug.
+metadata:
+  type: project
+---
+
+Executing the `utilitiescs-nullable-remediation` epic children (e.g. #364 HelperClasses) on branches off `epic/utilitiescs-nullable-remediation-integration`.
+
+**Why:** The recent HEAD commit changed the CI nullable gate from `/t:Build` (a silent no-op) to `/t:Rebuild`, so a genuine recompile now surfaces pre-existing warnings that `/p:TreatWarningsAsErrors=true` promotes to errors — across projects that are OUT of a given child's scope.
+
+**How to apply:**
+
+1. The plan-literal gate `msbuild TaskMaster.sln /t:Rebuild /p:TreatWarningsAsErrors=true` (no `/p:Nullable=enable`) FAILS at baseline, before any edit: vendored `SVGControl/SvgImageSelector.cs` has 2 pre-existing CS0649 (fields never assigned, dating to 2023) that halt the solution build early; and non-HelperClasses `UtilitiesCS` files (EmailIntelligence/, Extensions/) have ~28 CS0618 + 2 CS0168. None are fixable within a HelperClasses-scoped child. Flag them; do not treat as regressions.
+2. Authoritative CS86xx verification for a UtilitiesCS child: first build the solution once WITHOUT TWAE so SVGControl.dll exists, then `msbuild UtilitiesCS/UtilitiesCS.csproj /t:Rebuild /p:Configuration=Debug /p:Platform=AnyCPU /p:BuildProjectReferences=false` (no TWAE) and grep the output for `warning CS86`. CS86xx are severity-independent and arise only from `#nullable enable` files (project default is oblivious — `UtilitiesCS.csproj` has no `<Nullable>`), so zero CS86xx warnings == zero CS86xx errors under TWAE. `BuildProjectReferences=false` avoids re-triggering the SVGControl halt (UtilitiesCS has a project ref to SVGControl).
+3. Analyzer version drift: `UtilitiesCS.csproj`/`VBFunctions.csproj` `<Analyzer Include>` paths pin OLDER analyzer versions (Meziantou 3.0.101, SonarAnalyzer 10.27.0.140913, BannedApiAnalyzers 3.3.4) than `packages.config` (3.0.123 / 10.29.0.143774 / 5.6.0). `main` has the reconciling commit (097f0ba2) but the epic-integration base does not. `Sync-PackageReferences.ps1` only fixes `<HintPath>`, NOT `<Analyzer Include>`, so the analyzer build gets CS0006. Fix without touching tracked files: `nuget.exe install <id> -Version <old> -OutputDirectory packages` for the three csproj-referenced versions (packages/ is gitignored).
+4. `scripts/vscode/Invoke-MSTestWithCoverage.ps1` throws under StrictMode when discovery returns a SINGLE test assembly (`$testAssemblies.Count` on a scalar). To scope coverage to one assembly (e.g. UtilitiesCS.Test), invoke the underlying command directly: `dotnet-coverage collect --output <cobertura> --output-format cobertura --settings coverage.config -- <vstest> UtilitiesCS.Test\bin\Debug\UtilitiesCS.Test.dll /Settings:scripts/vscode/TaskMaster.cli.runsettings /InIsolation /TestCaseFilter:TestCategory!=LiveOutlook`.
+5. Env bootstrap on a fresh worktree: `Invoke-Restore.ps1` (nuget restore, 169 pkgs) then the analyzer install in (3). Global `csharpier` is v1.3.0 (subcommand syntax `csharpier check .` / `csharpier format .`, NOT `--check`); `dotnet tool run csharpier` fails because the repo-local .NET SDK is not installed.

.claude/agent-memory/feature-review/MEMORY.md

@@ -37,4 +37,5 @@
 - [SVGControl stale binding redirect out of scope](project_svgcontrol-stale-binding-redirect-out-of-scope.md) — #354: `SVGControl/app.config`'s `System.Runtime.CompilerServices.Unsafe` redirect (6.0.2.0 vs csproj 6.0.3.0) is still stale as of 2026-07-18; check it in any future app.config binding-redirect audit
 - [pr-context stale after remediation commit](project_pr-context-stale-after-remediation-commit.md) — #354 R4: pr_context artifacts don't auto-update after a remediation commit lands; compare `git rev-parse HEAD` against the summary's recorded Head ref every re-audit cycle and refresh if stale
 - [partial remediation still fails new-code floor](project_partial-remediation-new-code-floor-still-fails-209.md) — #209 R4: extracting one testable seam from a native-engine adapter raised coverage 0%->7.7%, real progress but still far below 85%/90%; recompute against the actual floor, don't trust a remediation-plan's weak ">0%" acceptance bar; recommend a maintainer exemption decision when the residual is architecturally irreducible
+- [nullable-epic full-solution TWAE is pre-existing](project_nullable-epic-fullsolution-twae-preexisting-blocker.md) — #364: utilitiescs-nullable-remediation children's plan-literal full-solution pragma-only TWAE build exits 1 on pre-existing out-of-scope SVGControl CS0649 + EmailIntelligence/Extensions CS0618; adjudicate DoD "toolchain passes" via the isolated UtilitiesCS.csproj build (EXIT 0, 0 CS86xx), not blocking
 - [coverage hook skips when no pr_context.summary.txt](coverage-hook-skips-when-no-pr-context-summary.md) — #367: absent pr_context summary makes changedLanguages empty, so the hook runs only the 3 artifact-path/location checks and skips all per-language coverage-row enforcement; still write clean PASS/FAIL rows; evidence/qa-gates/ is an allowed audit-artifact path

.claude/agent-memory/feature-review/project_nullable-epic-fullsolution-twae-preexisting-blocker.md

@@ -0,0 +1,29 @@
+---
+name: nullable-epic-fullsolution-twae-preexisting-blocker
+description: For utilitiescs-nullable-remediation epic children, the plan-literal full-solution pragma-only TWAE build exits 1 on pre-existing out-of-scope warnings, not on the child's work
+metadata:
+  type: project
+---
+
+Every child of the `utilitiescs-nullable-remediation` epic runs a per-file `#nullable enable`
+opt-in with a pragma-only verification build (`msbuild TaskMaster.sln /t:Rebuild ... /p:TreatWarningsAsErrors=true`,
+deliberately WITHOUT `/p:Nullable=enable`). That full-solution command exits 1 for a pre-existing,
+out-of-scope reason, not the child's annotations:
+
+- `SVGControl/SvgImageSelector.cs` 4x `CS0649` (vendored, 2023 WIP fields never assigned). SVGControl
+  builds early (project ref of UtilitiesCS) so the solution halts there.
+- Non-HelperClasses `UtilitiesCS/EmailIntelligence/` + `Extensions/` `CS0618` (obsolete AsyncEnumerable
+  APIs) + `CS0168`, promoted to errors by TWAE.
+
+This is the P0-T4 baseline (present before any child edit). It surfaced only after commit `20d163ac`
+changed the nullable gate from `/t:Build` (silent no-op) to `/t:Rebuild` (genuine recompile).
+
+**Why:** These files are outside the maintainer scope lock (`UtilitiesCS/HelperClasses/` only), so a
+child cannot fix them.
+
+**How to apply:** Adjudicate the DoD/AC "full toolchain passes" item as PASS for the in-scope
+obligation on the evidence that the ISOLATED build
+`msbuild UtilitiesCS/UtilitiesCS.csproj /t:Rebuild ... /p:BuildProjectReferences=false` exits 0 with
+zero CS86xx. Classify the full-solution TWAE exit 1 as pre-existing/out-of-scope, NOT a blocking
+in-scope defect. #364 (utilitiescs-nullable-helperclasses) confirmed all 42 opted-in files clean;
+`DvgForm.Designer.cs` stays oblivious (43rd file, not opted-in). Related: [[csharp-repowide-coverage-below-80]].

UtilitiesCS/HelperClasses/BinaryFlags/GenericBitwise.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Linq.Expressions;
@@ -10,10 +11,10 @@ namespace UtilitiesCS.HelperClasses
     public class GenericBitwise<TFlagEnum>
         where TFlagEnum : Enum
     {
-        private readonly Func<TFlagEnum, TFlagEnum, TFlagEnum> _and = null;
-        private readonly Func<TFlagEnum, TFlagEnum> _not = null;
-        private readonly Func<TFlagEnum, TFlagEnum, TFlagEnum> _or = null;
-        private readonly Func<TFlagEnum, TFlagEnum, TFlagEnum> _xor = null;
+        private readonly Func<TFlagEnum, TFlagEnum, TFlagEnum> _and;
+        private readonly Func<TFlagEnum, TFlagEnum> _not;
+        private readonly Func<TFlagEnum, TFlagEnum, TFlagEnum> _or;
+        private readonly Func<TFlagEnum, TFlagEnum, TFlagEnum> _xor;
 
         public GenericBitwise()
         {

UtilitiesCS/HelperClasses/CloningFunctions/DeepCompare.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
@@ -9,12 +10,14 @@ namespace UtilitiesCS.HelperClasses
 {
     public static class Deep
     {
-        public static List<(string, object, object)> DeepDifferences<T>(T obj1, T obj2)
+        public static List<(string, object?, object?)> DeepDifferences<T>(T obj1, T obj2)
         {
-            List<(string, object, object)> differences = new List<(string, object, object)>();
+            List<(string, object?, object?)> differences = new List<(string, object?, object?)>();
 
+            // Behavior-preserving `!`: throwIfNotFound: true guarantees a non-null Type (it
+            // throws otherwise), so dereferencing the result matches the prior behavior.
             var properties = DispatchUtility
-                .GetType(obj1, true)
+                .GetType(obj1!, true)!
                 .GetProperties(BindingFlags.Public | BindingFlags.Instance);
             //var properties = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
             foreach (var property in properties)
@@ -23,7 +26,7 @@ public static class Deep
                 var value2 = property.GetValue(obj2);
                 if (value1 != value2)
                 {
-                    differences.Add(($"{property.Name}", (object)value1, (object)value2));
+                    differences.Add(($"{property.Name}", value1, value2));
                 }
             }
             return differences;

UtilitiesCS/HelperClasses/CloningFunctions/DispatchUtility.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Reflection;
@@ -44,10 +45,10 @@ public static bool ImplementsIDispatch(object obj)
             SecurityAction.LinkDemand,
             Flags = SecurityPermissionFlag.UnmanagedCode
         )]
-        public static Type GetType(object obj, bool throwIfNotFound)
+        public static Type? GetType(object obj, bool throwIfNotFound)
         {
             RequireReference(obj, "obj");
-            Type result = GetType((IDispatchInfo)obj, throwIfNotFound);
+            Type? result = GetType((IDispatchInfo)obj, throwIfNotFound);
             return result;
         }
 
@@ -82,10 +83,10 @@ public static bool TryGetDispId(object obj, string name, out int dispId)
         /// <remarks>
         /// This can invoke a method or a property get accessor.
         /// </remarks>
-        public static object Invoke(object obj, int dispId, object[] args)
+        public static object? Invoke(object obj, int dispId, object[] args)
         {
             string memberName = "[DispId=" + dispId + "]";
-            object result = Invoke(obj, memberName, args);
+            object? result = Invoke(obj, memberName, args);
             return result;
         }
 
@@ -99,11 +100,11 @@ public static object Invoke(object obj, int dispId, object[] args)
         /// <remarks>
         /// This can invoke a method or a property get accessor.
         /// </remarks>
-        public static object Invoke(object obj, string memberName, object[] args)
+        public static object? Invoke(object obj, string memberName, object[] args)
         {
             RequireReference(obj, "obj");
             Type type = obj.GetType();
-            object result = type.InvokeMember(
+            object? result = type.InvokeMember(
                 memberName,
                 BindingFlags.InvokeMethod | BindingFlags.GetProperty,
                 null,
@@ -139,11 +140,11 @@ private static void RequireReference<T>(T value, string name)
         /// <param name="dispatch">An object that implements IDispatch.</param>
         /// <param name="throwIfNotFound">Whether an exception should be thrown if a Type can't be obtained.</param>
         /// <returns>A .NET Type that can be used with reflection.</returns>
-        private static Type GetType(IDispatchInfo dispatch, bool throwIfNotFound)
+        private static Type? GetType(IDispatchInfo dispatch, bool throwIfNotFound)
         {
             RequireReference(dispatch, "dispatch");
 
-            Type result = null;
+            Type? result = null;
             int typeInfoCount;
             int hr = dispatch.GetTypeInfoCount(out typeInfoCount);
             if (hr == S_OK && typeInfoCount > 0)
@@ -261,7 +262,8 @@ void GetTypeInfo(
                     UnmanagedType.CustomMarshaler,
                     MarshalTypeRef = typeof(System.Runtime.InteropServices.CustomMarshalers.TypeToTypeInfoMarshaler)
                 )]
-                    out Type typeInfo
+                // Nullable: the marshaled Type is only set when GetTypeInfoCount returned 1.
+                out Type? typeInfo
             );
 
             /// <summary>

UtilitiesCS/HelperClasses/CloningFunctions/ObjectCopier.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.IO;
 using System.Runtime.Serialization;
 using System.Runtime.Serialization.Formatters.Binary;
@@ -17,8 +18,10 @@ public static class ObjectCopier
         /// </summary>
         /// <typeparam name="T">The type of object being copied.</typeparam>
         /// <param name="source">The object instance to copy.</param>
-        /// <returns>A deep copy of the object.</returns>
-        public static T Clone<T>(T source)
+        /// <returns>A deep copy of the object, or <c>default</c> when <paramref name="source"/> is null.</returns>
+        // Deliberate downstream contract: the return is annotated `T?` because the null-source
+        // path returns default(T) (null for reference types). Callers must handle a possible null.
+        public static T? Clone<T>(T source)
         {
             if (!typeof(T).IsSerializable)
             {
@@ -33,7 +36,7 @@ public static T Clone<T>(T source)
             IFormatter formatter = new BinaryFormatter();
             formatter.Serialize(stream, source);
             stream.Seek(0, SeekOrigin.Begin);
-            return (T)formatter.Deserialize(stream);
+            return (T?)formatter.Deserialize(stream);
         }
     }
 }

UtilitiesCS/HelperClasses/DvgForm.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Data;
@@ -18,7 +19,7 @@ public DgvForm()
             InitializeComponent();
         }
 
-        private void DgvForm_ResizeEnd(object sender, EventArgs e)
+        private void DgvForm_ResizeEnd(object? sender, EventArgs e)
         {
             Debug.WriteLine($"Size is {this.Size.ToString()}");
         }

UtilitiesCS/HelperClasses/FileSystem/DirectoryInfoWrapper.cs

@@ -1,4 +1,5 @@
-using System;
+#nullable enable
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;

UtilitiesCS/HelperClasses/FileSystem/FileInfoWrapper.cs

@@ -1,3 +1,4 @@
+#nullable enable
 using System;
 using System.IO;
 using System.Linq;