Fix CS8602 nullable dereference in ToolbarBadgePage by PureWeen · Pull Request #34963 · dotnet/maui

PureWeen · 2026-04-14T19:03:23Z

Summary

Fix nullable dereference warnings (CS8602) in ToolbarBadgePage.cs that break Samples integration tests on both Windows and macOS.

Root Cause

PR #34669 ("Add BadgeText, BadgeColor, and BadgeTextColor support to ToolbarItem") introduced ToolbarBadgePage.cs where _statusLabel is initialized on line 68 but captured in lambda closures on lines 33, 46, and 60 — before the assignment. The compiler cannot prove non-null at the capture points, emitting CS8602 on all 3 lines across all TFMs.

Fix

Move _statusLabel initialization before the lambda closures that reference it. No behavioral change — the label object is the same, just created earlier in the constructor.

Validation

dotnet build Maui.Controls.Sample.csproj -f net11.0 -p:TreatWarningsAsErrors=true — 0 warnings, 0 errors

github-actions · 2026-04-14T19:03:32Z

🚀 Dogfood this PR with:

⚠️ WARNING: Do not do this without first carefully reviewing the code of this PR to satisfy yourself it is safe.

curl -fsSL https://github.com/dotnet/maui/main/eng/scripts/get-maui-pr.sh | bash -s -- 34963

Or

Run remotely in PowerShell:

iex "& { $(irm https://github.com/dotnet/maui/main/eng/scripts/get-maui-pr.ps1) } 34963"

Copilot

Pull request overview

Fixes CS8602 nullable dereference warnings in ToolbarBadgePage by ensuring _statusLabel is initialized before it’s captured by toolbar item click handlers, restoring warning-free builds with TreatWarningsAsErrors=true.

Changes:

Move _statusLabel initialization earlier in the constructor so lambda closures can safely reference it.
Remove the later duplicate _statusLabel initialization block.

PureWeen · 2026-04-14T21:52:44Z

/azp run maui-pr-uitests, maui-pr-devicetests

azure-pipelines · 2026-04-14T21:53:00Z

Azure Pipelines successfully started running 2 pipeline(s).

PureWeen · 2026-04-15T00:30:06Z

CI Failure Analysis

All CI failures on this PR are pre-existing on net11.0 and unrelated to our nullable fixes. Here's the full breakdown.

Failures Fixed by This PR

Error	File	Root Cause
CS8602 (lines 33, 46, 60)	`ToolbarBadgePage.cs`	`_statusLabel` captured in lambdas before initialization
CS8602 (lines 88, 94)	`UINSWindow.iOS.cs`	`PerformSelector`/`GetItem<T>` returns now nullable in macios SDK 26.2.11587
CS8602, CS8619 (lines 250, 258)	`AssertionExtensions.iOS.cs`	`GetCurrentContext()`/`GetImageFromCurrentImageContext()` now nullable
CS8622 (lines 87, 95)	`MauiTestApplicationDelegate.cs`	Lambda `sender` parameter nullability mismatch

Validation: Full solution build (Microsoft.Maui-mac.slnf) with TreatWarningsAsErrors=true passes with 0 errors locally. Windows Release build passed in CI. macOS build shows 0 CS errors (only fails on actool infra issue below).

Pre-existing CI Failures (Not Related to This PR)

1. WinUI UITests — All categories, 0/2500+ tests passing (app crash)

Error: OpenQA.Selenium.NoSuchWindowException: Currently selected window has been closed
The Windows HostApp crashes on launch before any test can run
Root cause: PR Add BadgeText, BadgeColor, and BadgeTextColor support to ToolbarItem #34669 ("Add BadgeText, BadgeColor, and BadgeTextColor support to ToolbarItem") merged Apr 9
Bisect evidence:

Build	Date	Source	WinUI Results
1369882	Apr 8	`c43df61b` (before #34669)	2,668 passed, 1 failed
1371858	Apr 9	`53be2cd6` (#34669 merged)	0 passed, 5,020 failed

2. macOS Debug Build — actool/ibtool failures

Error: iOS 26.2 Platform Not Installed / No simulator runtime version from ["22F77"] available to use with iphonesimulator SDK version 23C53
CI macOS agents have Xcode 26.2 but are missing the iOS 26.2 simulator runtime
Agent image was updated between Apr 7-14 (added Xcode 26.3/26.4), likely disrupting the iOS 26.2 runtime
Infrastructure issue — not fixable from code

3. AOT macOS — strip/dsymutil failures

Error: MauiPlatformInterop.framework/MauiPlatformInterop: No such file or directory
Known macios SDK bug — framework binary not produced during NativeAOT builds
Same failure on net11.0 baseline build 1376548

4. Windows Debug Build — File locking flake

MSB3026: Could not copy DLLs during build (file locked by another process)
Transient — passed on retry in previous builds

PureWeen · 2026-04-15T00:30:54Z

/rebase

Move _statusLabel initialization before the lambda closures that capture it, so the compiler can prove non-null at the dereference sites (lines 33, 46, 60). Fixes Samples windows and Samples macOS integration test failures introduced by #34669. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- UINSWindow.iOS.cs: Add null checks for PerformSelector and GetItem returns that are now nullable in macios SDK 26.2.11587 - AssertionExtensions.iOS.cs: Guard CGContext null from GetCurrentContext, use null-conditional on UIImage.Size - MauiTestApplicationDelegate.cs: Fix lambda sender parameter nullability to match updated MarshalManagedExceptionHandler/MarshalObjectiveCExceptionHandler delegate signatures Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

This reverts commit 4e6b863.

## Problem PR #34669 (ToolbarItem Badge Support) added Issue8305_Toolbar.cs with `[Issue(IssueTracker.Github, 8305, ...)]`, but Issue8305.cs (Shell Badge, from PR #34659) already uses issue number 8305. Both generated the same `DisplayName = "G8305"`, causing `VerifyNoDuplicates()` in `TestCases.cs` to throw `NotSupportedException` at app startup, crashing the **entire HostApp** and failing **ALL** Windows UI tests (not just toolbar tests). This crash has been present since build [1371858](https://dev.azure.com/dnceng-public/public/_build/results?buildId=1371858) (PR #34669 merge). The follow-up PR #34963 fixed nullable warnings but did not address this crash. ## Root Cause `TestCases.cs:VerifyNoDuplicates()` (line 161-175) uses a HashSet to check for duplicate `DisplayName` values. When two `[Issue]` attributes share the same tracker and number with default `issueTestNumber=0`, they produce identical display names, triggering the crash. ## Fix 1. **Add `issueTestNumber: 1`** to `Issue8305_Toolbar`'s `[Issue]` attribute, producing unique `DisplayName = "G8305 (1)"` instead of duplicate `"G8305"` 2. **Replace non-existent icon images** (`envelope.png`, `bell.png`, `cart.png`) with images that exist in HostApp resources (`bank.png`, `calculator.png`, `shopping_cart.png`) ## Verification - Both `Controls.TestCases.HostApp` (Windows TFM) and `Controls.TestCases.Shared.Tests` build successfully - The `issueTestNumber` pattern is well-established (used by Issue11769, Issue13126_2, Issue1583_1, Issue28986_Border, and others) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings April 14, 2026 19:03

Copilot started reviewing on behalf of PureWeen April 14, 2026 19:04 View session

Copilot AI reviewed Apr 14, 2026

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github-actions Bot and others added 2 commits April 15, 2026 00:31

github-actions Bot force-pushed the fix/toolbar-badge-nullable branch from 5ee1db7 to 6746c83 Compare April 15, 2026 00:31

This was referenced Apr 15, 2026

The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008

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[android-arm64] The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#6408

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github-actions Bot mentioned this pull request Apr 15, 2026

[repo-status] Daily Repo Status - April 15, 2026 🌟 #34966

Closed

jfversluis approved these changes Apr 15, 2026

View reviewed changes

jfversluis merged commit 4e6b863 into net11.0 Apr 15, 2026
13 of 34 checks passed

jfversluis deleted the fix/toolbar-badge-nullable branch April 15, 2026 07:29

jfversluis added a commit that referenced this pull request Apr 15, 2026

Revert "Fix CS8602 nullable dereference in ToolbarBadgePage (#34963)"

d2c1e0d

This reverts commit 4e6b863.

jfversluis mentioned this pull request Apr 15, 2026

Revert ToolbarItem Badge feature (#34669) and follow-up (#34963) #34984

Closed

PureWeen mentioned this pull request Apr 15, 2026

Pin iOS simulator version to match selected Xcode in provisioning #34978

Merged

github-actions Bot mentioned this pull request Apr 16, 2026

[repo-status] 🌟 Daily Repo Status - April 16, 2026 #34990

Closed

jfversluis mentioned this pull request Apr 16, 2026

Fix duplicate issue number crash breaking all Windows UI tests #34991

Merged

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Fix CS8602 nullable dereference in ToolbarBadgePage#34963

Fix CS8602 nullable dereference in ToolbarBadgePage#34963
jfversluis merged 2 commits intonet11.0from
fix/toolbar-badge-nullable

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PureWeen commented Apr 14, 2026

Summary

Root Cause

Fix

Validation

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Pull request overview

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PureWeen commented Apr 14, 2026

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azure-pipelines Bot commented Apr 14, 2026

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PureWeen commented Apr 15, 2026

CI Failure Analysis

Failures Fixed by This PR

Pre-existing CI Failures (Not Related to This PR)

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github-actions Bot commented Apr 14, 2026 •

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