fix(test): define the xUnit constant that generated code actually reads

The SDK defined XUNIT_ENTRYPOINT_DISABLE_WARNINGS, but no xUnit release
ever read it: 4.0.0 had no such switch, and 4.0.1 shipped it as
XUNIT_GENERATED_DISABLE_WARNINGS, extended to its AOT source generation.
Analyzer warnings in xUnit's generated entry point therefore stayed live
and could fail a warnings-as-errors build. The SDK now defines the shipped
name; EnableXunitEntryPointDisableWarnings remains the opt-out.

The consumer smoke test now asserts that xUnit's generated entry point
tests the constant the SDK defines, so a future upstream rename fails the
suite instead of silently disabling the suppression.

See xunit/xunit#3606

Author: xshaheen

README.md

@@ -257,7 +257,7 @@ the listed default; explicit values win unless the behavior is identified as man
 | `HeadlessCoverageSettingsPath` | packaged Test SDK path | Absolute path to the SDK-owned `default.runsettings`; query this evaluated property when an external runner needs the canonical coverage denominator policy. |
 | `EnableDefaultTestSettings` | enabled unless `false` | Set `false` to own all MTP command-line defaults. |
 | `MinimumExpectedTests` | `1` | Sets the MTP minimum-test guard. Set `0` to omit only the SDK-supplied `--minimum-expected-tests` argument; this does not guarantee that a zero-test run succeeds. |
-| `EnableXunitEntryPointDisableWarnings` | `true` when a supported xUnit v3 package is directly referenced | Set `false` to prevent the SDK from adding `XUNIT_ENTRYPOINT_DISABLE_WARNINGS`. |
+| `EnableXunitEntryPointDisableWarnings` | `true` when a supported xUnit v3 package is directly referenced | xUnit v3 4.0.1 and later wrap their generated entry point and AOT source in `#pragma warning disable` when `XUNIT_GENERATED_DISABLE_WARNINGS` is defined, so analyzer warnings cannot fail a build on code the consumer does not own. Set `false` to prevent the SDK from adding the constant. |
 | `OptimizeTestRun` | enabled unless `false` | Set `false` to keep analyzers enabled during MTP's test-build phase. |
 | `DisableSupportPackageInformation` | `false` | Set `true` to opt out of Headless package metadata and symbol policy. |
 | `SearchReadmeFileAbove` | `false` | Searches parent directories for a package README. |

src/Headless.NET.Sdk.Test/README.md

@@ -75,7 +75,7 @@ maintain a consumer-owned runsettings file.
 - Microsoft Testing Platform only; VSTest and `Microsoft.NET.Test.Sdk` are not injected.
 - Restore-visible crash dump, hang dump, hot reload, retry, TRX, and coverage extensions.
 - Default TRX output, crash and hang dumps, and `MinimumExpectedTests=1`. Set it to a positive value to change the MTP guard, or `0` to omit only the SDK-supplied argument; omission does not guarantee that a zero-test run succeeds. `EnableDefaultTestSettings=false` removes all SDK-owned MTP arguments.
-- A direct supported xUnit v3 package reference adds `XUNIT_ENTRYPOINT_DISABLE_WARNINGS` once while preserving other constants. Set `EnableXunitEntryPointDisableWarnings=false` to opt out; test-project classification alone does not enable it.
+- A direct supported xUnit v3 package reference adds `XUNIT_GENERATED_DISABLE_WARNINGS` once while preserving other constants; xUnit v3 4.0.1 and later then suppress warnings in their generated code. Set `EnableXunitEntryPointDisableWarnings=false` to opt out; test-project classification alone does not enable it.
 - Coverage enabled on CI, with `HeadlessCoverageSettingsPath` exposing the packaged denominator policy, and analyzer work skipped during the test-build phase unless explicitly retained.
 - Mandatory Headless analyzer infrastructure, configurable banned-API policy, and mandatory audit and CI policies with narrow test-code severity relaxations.
 

src/Headless.NET.Sdk/build/SupportTestProjects.targets

@@ -111,7 +111,12 @@
       >$(TestingPlatformCommandLineArguments) --minimum-expected-tests $(MinimumExpectedTests)TestingPlatformCommandLineArguments>
   PropertyGroup>
 
-  
+  
   <PropertyGroup>
     <_HeadlessXunitEntryPointDisableWarningsTarget>_HeadlessConfigureXunitEntryPointDisableWarnings_HeadlessXunitEntryPointDisableWarningsTarget>
   PropertyGroup>
@@ -132,15 +137,15 @@
       <EnableXunitEntryPointDisableWarnings Condition="'$(EnableXunitEntryPointDisableWarnings)' == ''"
         >trueEnableXunitEntryPointDisableWarnings>
       <_HeadlessXunitEntryPointDisableWarningsAlreadyDefined Condition="'$(MSBuildProjectExtension)' == '.vbproj'"
-        >$([System.String]::Copy(',$(DefineConstants),').Contains(',XUNIT_ENTRYPOINT_DISABLE_WARNINGS=-1,'))_HeadlessXunitEntryPointDisableWarningsAlreadyDefined>
+        >$([System.String]::Copy(',$(DefineConstants),').Contains(',XUNIT_GENERATED_DISABLE_WARNINGS=-1,'))_HeadlessXunitEntryPointDisableWarningsAlreadyDefined>
       <_HeadlessXunitEntryPointDisableWarningsAlreadyDefined Condition="'$(MSBuildProjectExtension)' != '.vbproj'"
-        >$([System.String]::Copy(';$(DefineConstants);').Contains(';XUNIT_ENTRYPOINT_DISABLE_WARNINGS;'))_HeadlessXunitEntryPointDisableWarningsAlreadyDefined>
+        >$([System.String]::Copy(';$(DefineConstants);').Contains(';XUNIT_GENERATED_DISABLE_WARNINGS;'))_HeadlessXunitEntryPointDisableWarningsAlreadyDefined>
       <DefineConstants
         Condition="'$(_HeadlessXunitEntryPointDisableWarningsAlreadyDefined)' != 'true' AND '$(MSBuildProjectExtension)' == '.vbproj'"
-        >$(DefineConstants),XUNIT_ENTRYPOINT_DISABLE_WARNINGS=-1DefineConstants>
+        >$(DefineConstants),XUNIT_GENERATED_DISABLE_WARNINGS=-1DefineConstants>
       <DefineConstants
         Condition="'$(_HeadlessXunitEntryPointDisableWarningsAlreadyDefined)' != 'true' AND '$(MSBuildProjectExtension)' != '.vbproj'"
-        >$(DefineConstants);XUNIT_ENTRYPOINT_DISABLE_WARNINGSDefineConstants>
+        >$(DefineConstants);XUNIT_GENERATED_DISABLE_WARNINGSDefineConstants>
     PropertyGroup>
   Target>
 

tests/Headless.NET.Sdk.Tests.Integrations/ContractConsumerBehaviorTests.Testing.cs

@@ -45,7 +45,7 @@ public async Task should_restore_required_mtp_extensions_and_run_a_clean_consume
             additionalFiles: new Dictionary<string, string>(StringComparer.Ordinal)
             {
                 ["ContractSmokeTests.cs"] =
-                    "#if !XUNIT_ENTRYPOINT_DISABLE_WARNINGS\n#error XUNIT_ENTRYPOINT_DISABLE_WARNINGS is not defined\n#endif\nusing Xunit; namespace ConsumerProject; public sealed class ContractSmokeTests { [Fact] public void passes() => Assert.True(true); }",
+                    "#if !XUNIT_GENERATED_DISABLE_WARNINGS\n#error XUNIT_GENERATED_DISABLE_WARNINGS is not defined\n#endif\nusing Xunit; namespace ConsumerProject; public sealed class ContractSmokeTests { [Fact] public void passes() => Assert.True(true); }",
             }
         );
         await UpdateProjectAsync(
@@ -117,5 +117,20 @@ await UpdateProjectAsync(
             $"{test.Output}{Environment.NewLine}Evaluated properties:{Environment.NewLine}{evaluation.Output}"
         );
         Assert.Contains("Passed", test.Output, StringComparison.OrdinalIgnoreCase);
+
+        // The SDK-defined constant only helps when it is the name xUnit's generated code tests for;
+        // a renamed upstream symbol would otherwise leave the suppression silently inert.
+        var entryPoint = Assert.Single(
+            Directory.EnumerateFiles(
+                Path.Combine(project.RootDirectory, "obj"),
+                "XunitAutoGeneratedEntryPoint.cs",
+                SearchOption.AllDirectories
+            )
+        );
+        Assert.Contains(
+            "#if XUNIT_GENERATED_DISABLE_WARNINGS",
+            await File.ReadAllTextAsync(entryPoint, TestContext.Current.CancellationToken),
+            StringComparison.Ordinal
+        );
     }
 }

tests/Headless.NET.Sdk.Tests.Integrations/SdkIntegrationTests.ProjectTypes.cs

@@ -212,13 +212,13 @@ bool useSdkConsumption
 
         Assert.Equal("true", properties["EnableXunitEntryPointDisableWarnings"]);
         Assert.Contains("UNRELATED_CONSTANT", constants);
-        Assert.Single(constants, constant => constant == "XUNIT_ENTRYPOINT_DISABLE_WARNINGS");
+        Assert.Single(constants, constant => constant == "XUNIT_GENERATED_DISABLE_WARNINGS");
     }
 
     [Theory]
     [InlineData("false", "UNRELATED_CONSTANT", 0)]
-    [InlineData(null, "UNRELATED_CONSTANT;XUNIT_ENTRYPOINT_DISABLE_WARNINGS", 1)]
-    [InlineData(null, "UNRELATED_XUNIT_ENTRYPOINT_DISABLE_WARNINGS_CONSTANT", 1)]
+    [InlineData(null, "UNRELATED_CONSTANT;XUNIT_GENERATED_DISABLE_WARNINGS", 1)]
+    [InlineData(null, "UNRELATED_XUNIT_GENERATED_DISABLE_WARNINGS_CONSTANT", 1)]
     public async Task should_respect_xunit_entrypoint_warning_constant_overrides(
         string? optOut,
         string initialConstants,
@@ -250,7 +250,7 @@ int expectedConstantCount
 
         Assert.Equal(
             expectedConstantCount,
-            constants.Count(constant => constant == "XUNIT_ENTRYPOINT_DISABLE_WARNINGS")
+            constants.Count(constant => constant == "XUNIT_GENERATED_DISABLE_WARNINGS")
         );
         Assert.Contains(initialConstants.Split(';')[0], constants);
     }
@@ -268,7 +268,7 @@ public async Task should_not_infer_xunit_entrypoint_warning_constant_from_test_p
         var properties = await project.EvaluateHeadlessPropertiesAsync();
 
         Assert.Empty(properties["EnableXunitEntryPointDisableWarnings"]);
-        Assert.DoesNotContain("XUNIT_ENTRYPOINT_DISABLE_WARNINGS", properties["DefineConstants"]);
+        Assert.DoesNotContain("XUNIT_GENERATED_DISABLE_WARNINGS", properties["DefineConstants"]);
     }
 
     [Fact]