Line pragma assertions fail in design time

[333fred]

Consider this test:

    [IntegrationTestFact]
    public void LinePragmas()
    {
        var generated = CompileToCSharp("""
            @{
            <div>test</div>
            }
            @{
            <div>test</div>
            }
            """);

        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
        AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
        CompileToAssembly(generated);
    }

After generating the baselines, this test will fail to validate line pragmas; no line pragmas will generate for any of the 4 source mappings in design time. Given our move to FUSE, I'm unsure whether this is actually important to solve, or whether it indicates that we may have a test gap in our FUSE generation. @chsienki for thoughts.

[333fred]

No line pragma found for code at line 1.
   at Microsoft.AspNetCore.Razor.Language.IntegrationTests.RazorBaselineIntegrationTestBase.AssertLinePragmas(RazorCodeDocument codeDocument) in /home/fred/git/razor/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorBaselineIntegrationTestBase.cs:line 171
   at Microsoft.AspNetCore.Razor.Language.IntegrationTests.RazorBaselineIntegrationTestBase.AssertCSharpDocumentMatchesBaseline(RazorCodeDocument codeDocument, Boolean verifyLinePragmas, String testName) in /home/fred/git/razor/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorBaselineIntegrationTestBase.cs:line 145
   at Microsoft.AspNetCore.Razor.Language.IntegrationTests.ComponentPreprocessorDirectiveTest.LinePragmas() in /home/fred/git/razor/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentPreprocessorDirectiveTest.cs:line 257
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

[333fred]

Another example (with the changes in my directives branch):

    [IntegrationTestFact]
    public void AfterTag()
    {
        var generated = CompileToCSharp("""
            @{
                <div>
            #if true
                <div>
            }
            @{
            #endif
            }
            """);

        AssertDocumentNodeMatchesBaseline(generated.CodeDocument);
        if (!DesignTime)
        {
            // https://github.com/dotnet/razor/issues/10981
            AssertCSharpDocumentMatchesBaseline(generated.CodeDocument);
        }
        CompileToAssembly(generated,
            // x:\dir\subdir\Test\TestComponent.cshtml(7,1): error CS1028: Unexpected preprocessor directive
            // #endif
            Diagnostic(ErrorCode.ERR_UnexpectedDirective, "#endif").WithLocation(7, 1));
    }

No line pragma found for code at line 1.
   at Microsoft.AspNetCore.Razor.Language.IntegrationTests.RazorBaselineIntegrationTestBase.AssertLinePragmas(RazorCodeDocument codeDocument) in /home/fred/git/razor/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorBaselineIntegrationTestBase.cs:line 171
   at Microsoft.AspNetCore.Razor.Language.IntegrationTests.RazorBaselineIntegrationTestBase.AssertCSharpDocumentMatchesBaseline(RazorCodeDocument codeDocument, Boolean verifyLinePragmas, String testName) in /home/fred/git/razor/src/Shared/Microsoft.AspNetCore.Razor.Test.Common/Language/IntegrationTests/RazorBaselineIntegrationTestBase.cs:line 145
   at Microsoft.AspNetCore.Razor.Language.IntegrationTests.ComponentPreprocessorDirectiveTest.AfterTag() in /home/fred/git/razor/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentPreprocessorDirectiveTest.cs:line 136
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Void** arguments, Signature sig, Boolean isConstructor)
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

[chsienki]

@333fred Yep, I've come accross this before. We actually added the assertion as part of fuse to make sure we didn't miss anything and at the time it held true for design time. As we've added tests we've started seeing places it no longer holds for design time. I don't think its worth altering the design time code to fix it.

In #10907 I added a flag that lets you skip these asserts for design time:

razor/src/Compiler/Microsoft.AspNetCore.Razor.Language/test/IntegrationTests/ComponentCodeGenerationTestBase.cs

Lines 5595 to 5596 in ef8467d

	// Design time writer doesn't correctly emit pragmas for missing tokens, so don't validate them in design time
	AssertCSharpDocumentMatchesBaseline(generated.CodeDocument, verifyLinePragmas: !DesignTime);