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Fix NoWarn ignored when MSBuildWarningsAsMessages is set #12828

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Merged
JanProvaznik merged 3 commits into from
Nov 26, 2025
Merged

Fix NoWarn ignored when MSBuildWarningsAsMessages is set #12828

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f54d120
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Copilot Nov 25, 2025
35a2f65
Fix NoWarn being ignored when MSBuildWarningsAsMessages is set
Copilot Nov 25, 2025
27f3f04
Fix issue reference and add test for duplicate diagnostic codes
Copilot Nov 25, 2025
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118 changes: 118 additions & 0 deletions src/Build.UnitTests/WarningsAsMessagesAndErrors_Tests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -555,5 +555,123 @@ public void MSBuildWarningsAsMessagesWithCommaSeparation()
logger.ErrorCount.ShouldBe(0);
}
}

/// <summary>
/// NoWarn should be honored in addition to MSBuildWarningsAsMessages when both are set.
/// This tests the fix in Microsoft.Common.CurrentVersion.targets where NoWarn was ignored
/// if MSBuildWarningsAsMessages was already set.
/// See: https://github.com/dotnet/msbuild/issues/12808
/// </summary>
[Fact]
public void NoWarnHonoredWhenMSBuildWarningsAsMessagesIsSetViaTargets()
{
using (TestEnvironment env = TestEnvironment.Create(_output))
{
// NoWarn sets NAT013, MSBuildWarningsAsMessages sets NAT011 and NAT012
// Both should be treated as messages (not warnings) when Common targets are imported
var content = """
<Project DefaultTargets="Build" xmlns="msbuildnamespace" ToolsVersion="msbuilddefaulttoolsversion">
<Import Project="$(MSBuildToolsPath)\Microsoft.Common.props"/>

<PropertyGroup>
<Platform>AnyCPU</Platform>
<Configuration>Debug</Configuration>
<OutputPath>bin\Debug</OutputPath>
<NoWarn>NAT013</NoWarn>
<MSBuildWarningsAsMessages>NAT011;NAT012</MSBuildWarningsAsMessages>
</PropertyGroup>

<Import Project="$(MSBuildToolsPath)\Microsoft.Common.targets"/>

<Target Name="Build">
<Warning Code="NAT011" Text="Warning from MSBuildWarningsAsMessages 1" />
<Warning Code="NAT012" Text="Warning from MSBuildWarningsAsMessages 2" />
<Warning Code="NAT013" Text="Warning from NoWarn" />
</Target>
</Project>
""";
TransientTestProjectWithFiles proj = env.CreateTestProjectWithFiles(content);

MockLogger logger = proj.BuildProjectExpectSuccess();
logger.WarningCount.ShouldBe(0);
logger.ErrorCount.ShouldBe(0);
}
}

/// <summary>
/// NoWarn should work when MSBuildWarningsAsMessages is NOT set via targets (original behavior).
/// </summary>
[Fact]
public void NoWarnWorksWhenMSBuildWarningsAsMessagesIsNotSetViaTargets()
{
using (TestEnvironment env = TestEnvironment.Create(_output))
{
// NoWarn sets NAT013, MSBuildWarningsAsMessages is not set
// NAT013 should be treated as a message (not a warning) when Common targets are imported
var content = """
<Project DefaultTargets="Build" xmlns="msbuildnamespace" ToolsVersion="msbuilddefaulttoolsversion">
<Import Project="$(MSBuildToolsPath)\Microsoft.Common.props"/>

<PropertyGroup>
<Platform>AnyCPU</Platform>
<Configuration>Debug</Configuration>
<OutputPath>bin\Debug</OutputPath>
<NoWarn>NAT013</NoWarn>
</PropertyGroup>

<Import Project="$(MSBuildToolsPath)\Microsoft.Common.targets"/>

<Target Name="Build">
<Warning Code="NAT013" Text="Warning from NoWarn" />
</Target>
</Project>
""";
TransientTestProjectWithFiles proj = env.CreateTestProjectWithFiles(content);

MockLogger logger = proj.BuildProjectExpectSuccess();
logger.WarningCount.ShouldBe(0);
logger.ErrorCount.ShouldBe(0);
}
}

/// <summary>
/// Duplicate diagnostic codes in both NoWarn and MSBuildWarningsAsMessages should be handled correctly.
/// When the same code appears in both properties, the warning should still be treated as a message.
/// </summary>
[Fact]
public void DuplicateDiagnosticCodesInNoWarnAndMSBuildWarningsAsMessagesAreHandled()
{
using (TestEnvironment env = TestEnvironment.Create(_output))
{
// NAT012 is in both NoWarn and MSBuildWarningsAsMessages
// This tests that duplicate codes are handled correctly
var content = """
<Project DefaultTargets="Build" xmlns="msbuildnamespace" ToolsVersion="msbuilddefaulttoolsversion">
<Import Project="$(MSBuildToolsPath)\Microsoft.Common.props"/>

<PropertyGroup>
<Platform>AnyCPU</Platform>
<Configuration>Debug</Configuration>
<OutputPath>bin\Debug</OutputPath>
<NoWarn>NAT012;NAT013</NoWarn>
<MSBuildWarningsAsMessages>NAT011;NAT012</MSBuildWarningsAsMessages>
</PropertyGroup>

<Import Project="$(MSBuildToolsPath)\Microsoft.Common.targets"/>

<Target Name="Build">
<Warning Code="NAT011" Text="Warning from MSBuildWarningsAsMessages only" />
<Warning Code="NAT012" Text="Warning from both NoWarn and MSBuildWarningsAsMessages" />
<Warning Code="NAT013" Text="Warning from NoWarn only" />
</Target>
</Project>
""";
TransientTestProjectWithFiles proj = env.CreateTestProjectWithFiles(content);

MockLogger logger = proj.BuildProjectExpectSuccess();
logger.WarningCount.ShouldBe(0);
logger.ErrorCount.ShouldBe(0);
}
}
}
}
2 changes: 1 addition & 1 deletion src/Tasks/Microsoft.Common.CurrentVersion.targets
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Expand Up @@ -666,7 +666,7 @@ Copyright (C) Microsoft Corporation. All rights reserved.

<!-- Users familiar with how some other repos work try to use NoWarn with MSBuild in place of MSBuildWarningsAsMessages. -->
<PropertyGroup>
<MSBuildWarningsAsMessages Condition="'$(MSBuildWarningsAsMessages)'==''">$(NoWarn)</MSBuildWarningsAsMessages>
<MSBuildWarningsAsMessages>$(MSBuildWarningsAsMessages);$(NoWarn)</MSBuildWarningsAsMessages>
<MSBuildWarningsAsErrors Condition="'$(MSBuildWarningsAsErrors)'==''">$(WarningsAsErrors)</MSBuildWarningsAsErrors>
<MSBuildWarningsNotAsErrors Condition="'$(MSBuildWarningsNotAsErrors)'==''">$(WarningsNotAsErrors)</MSBuildWarningsNotAsErrors>
</PropertyGroup>
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