Handling an edge case where usings are reordered inside of a namespac… (#1543)

…e inside of an #if

Author: belav

Src/CSharpier.Tests/CommandLineFormatterTests.cs

@@ -678,6 +678,34 @@ public void File_With_Reorder_Modifiers_In_If_Directive_Should_Pass_Validation(s
         result.OutputLines.First().Should().StartWith("Formatted 1 files in");
     }
 
+    [Test]
+    public void File_With_Reordered_Usings_In_If_Directive_Should_Pass_Validation()
+    {
+        var context = new TestContext();
+
+        context.WhenAFileExists(
+            "file1.cs",
+            """
+            #if NOT_UNTIL_LATER
+            namespace Namespace {
+                
+                using System.Xml;
+                using System.Configuration;
+                
+                public class ClassName {
+
+                }
+            }
+            #endif
+            """
+        );
+
+        var result = Format(context);
+
+        result.ErrorOutputLines.Should().BeEmpty();
+        result.OutputLines.First().Should().StartWith("Formatted 1 files in");
+    }
+
     [Test]
     public void File_With_Added_Trailing_Comma_Before_Comment_Should_Pass_Validation()
     {

Src/CSharpier/SyntaxPrinter/UsingDirectives.cs

@@ -124,7 +124,16 @@ var groupOfUsingData in GroupUsings(
             }
         }
 
-        if (reorderedDirectives && usings.Any(o => o.ToFullString().Contains("#endif")))
+        if (
+            reorderedDirectives
+            && (
+                usings.Any(o => o.ToFullString().Contains("#endif"))
+                || (
+                    usings[0].Parent is NamespaceDeclarationSyntax namespaceDeclarationSyntax
+                    && namespaceDeclarationSyntax.GetLeadingTrivia().ToFullString().Contains("#if")
+                )
+            )
+        )
         {
             context.State.ReorderedUsingsWithDisabledText = true;
         }