Only add newline before #ifdef block if other lines preceded it

Author: calcmogul

wpiformat/test/test_includeorder.py

@@ -499,4 +499,12 @@ def test_includeorder():
     test.add_input("./Test.h", "// #included here" + os.linesep)
     test.add_output("// #included here" + os.linesep, False, True)
 
+    # Ensure extra newline isn't inserted between #pragma and #ifdef
+    test.add_input("./Test.h",
+        "#pragma once" + os.linesep + \
+        os.linesep + \
+        "#ifdef _MSC_VER" + os.linesep + \
+        "#endif" + os.linesep)
+    test.add_latest_input_as_output(True)
+
     test.run(OutputType.FILE)

wpiformat/wpiformat/includeorder.py

@@ -268,7 +268,11 @@ def header_sort(self, config_file, lines_list, file_name, start, end,
                         else:
                             # Treat #ifdef as barrier and flush includes
                             output_list.extend(self.write_headers(includes))
-                            output_list.append("")
+                            if output_list:
+                                # Only add newline if content already exists in
+                                # output_list that needs to be delimited from
+                                # the #ifdef
+                                output_list.append("")
                             includes = [[], [], [], [], []]
 
                             output_list.append(ifdef)