Don't warn on app.UseEndpoints(e => {}); (#48977)

* Update the analyzer to warn only if there are actual invocations in the body of the UseEndpoints delegate.

* Move check to separate method and remove diagnostic marker in test source code.

---------

Co-authored-by: Bethel Arthur <[email protected]>

Author: BArthur1972

src/Framework/AspNetCoreAnalyzers/src/Analyzers/WebApplicationBuilder/WebApplicationBuilderAnalyzer.cs

@@ -328,6 +328,11 @@ private static bool IsDisallowedMethod(
             return false;
         }
 
+        if (!HasInvocationInBody(disallowedMethodName, invocation))
+        {
+            return false;
+        }
+
         return true;
 
         static bool IsDisallowedMethod(
@@ -353,4 +358,30 @@ static bool IsDisallowedMethod(
             return false;
         }
     }
+
+    private static bool HasInvocationInBody(string disallowedMethodName, IInvocationOperation invocation)
+    {
+        if (string.Equals(disallowedMethodName, "UseEndpoints", StringComparison.Ordinal))
+        {
+            foreach (var argument in invocation.Arguments)
+            {
+                var arguments = argument?.Syntax as ArgumentSyntax;
+                var lambdaExpression = arguments?.Expression as SimpleLambdaExpressionSyntax;
+
+                if (lambdaExpression?.Body is BlockSyntax block)
+                {
+                    foreach (var statement in block.Statements)
+                    {
+                        if (statement is ExpressionStatementSyntax expressionStatement && expressionStatement.Expression is InvocationExpressionSyntax)
+                        {
+                            return true; // Method invocation found, so the diagnostic should be triggered
+                        }
+                    }
+                    return false; // Empty block, no method invocation, so the diagnostic should not be triggered
+                }
+            }
+        }
+
+        return true;
+    }
 }

src/Framework/AspNetCoreAnalyzers/test/WebApplicationBuilder/UseTopLevelRouteRegistrationInsteadOfUseEndpointsTest.cs

@@ -35,7 +35,7 @@ public async Task DoesNotWarnWhenEndpointRegistrationIsTopLevel()
     }
 
     [Fact]
-    public async Task DoesNotWarnWhenEnpointRegistrationIsTopLevel_InMain()
+    public async Task DoesNotWarnWhenEndpointRegistrationIsTopLevel_InMain()
     {
         //arrange
         var source = @"
@@ -58,6 +58,48 @@ public static void Main (string[] args)
         Assert.Empty(diagnostics);
     }
 
+    [Fact]
+    public async Task DoesNotWarnWhenEndpointRegistrationIsNotTopLevel_NoInvocation()
+    {
+        //arrange
+        var source = TestSource.Read(@"
+using Microsoft.AspNetCore.Builder;
+var builder = WebApplication.CreateBuilder(args);
+var app = builder.Build();
+app.UseRouting();
+app.UseEndpoints(e => { });
+");
+        //act
+        var diagnostics = await Runner.GetDiagnosticsAsync(source.Source);
+
+        //assert
+        Assert.Empty(diagnostics);
+    }
+
+    [Fact]
+    public async Task DoesNotWarnWhenEndpointRegistrationIsNotTopLevel_NoInvocation_InMain()
+    {
+        //arrange
+        var source = TestSource.Read(@"
+using Microsoft.AspNetCore.Builder;
+public static class Program
+{
+    public static void Main (string[] args)
+    {
+        var builder = WebApplication.CreateBuilder(args);
+        var app = builder.Build();
+        app.UseRouting();
+        app.UseEndpoints(e => { });
+    }
+}
+");
+        //act
+        var diagnostics = await Runner.GetDiagnosticsAsync(source.Source);
+
+        //assert
+        Assert.Empty(diagnostics);
+    }
+
     [Fact]
     public async Task WarnsWhenEndpointRegistrationIsNotTopLevel()
     {
@@ -226,4 +268,5 @@ public async Task WarnsTwiceWhenEndpointRegistrationIsNotTopLevel_OnDifferentLin
         AnalyzerAssert.DiagnosticLocation(source.MarkerLocations["MM2"], diagnostic2.Location);
         Assert.Equal("Suggest using top level route registrations instead of UseEndpoints", diagnostic2.GetMessage(CultureInfo.InvariantCulture));
     }
+
 }