Generate parser files with same newlines as come in

Author: timfel

graalpython/com.oracle.graal.python.frozen/freeze_modules.py

@@ -607,6 +607,7 @@ def write_frozen_module_file(file, modules):
         stat_result = os.stat(file)
         atime, mtime = stat_result.st_atime, stat_result.st_mtime
     else:
+        linesep = os.linesep
         content = None
     os.makedirs(os.path.dirname(file), exist_ok=True)
     with open(file, "w", encoding="utf-8", newline=linesep) as out_file:

graalpython/com.oracle.graal.python.pegparser.generator/CMakeLists.txt

@@ -37,10 +37,7 @@ add_custom_target(grammar ALL
     DEPENDS "${PARSER_OUTPUT}")
 add_custom_command(
     OUTPUT "${PARSER_OUTPUT}"
-    COMMAND ${PYTHON_EXE} "${CMAKE_CURRENT_LIST_DIR}/main_parser_gen.py" "${GRAMMAR}" "${TOKENS}" "${PARSER_OUTPUT}"
-    COMMAND ${CMAKE_COMMAND} -E copy_if_different
-            ${PARSER_OUTPUT}
-	    ${PARSER_TARGET}
+    COMMAND ${PYTHON_EXE} "${CMAKE_CURRENT_LIST_DIR}/main_parser_gen.py" "${GRAMMAR}" "${TOKENS}" "${PARSER_TARGET}"
     DEPENDS "${CMAKE_CURRENT_LIST_DIR}/main_parser_gen.py" "${GRAMMAR}" "${TOKENS}" "${PARSER_TARGET}" ${PEGEN_FILES} ${PEGJAVA_FILES})
 
 add_custom_target(asdl ALL 

graalpython/com.oracle.graal.python.pegparser.generator/asdl/java_file.py

@@ -131,7 +131,24 @@ def define(self, line: str, *annotations: str):
 def create(out_dir_base: str, java_package: str, java_class_name: str):
     sst_dir = os.path.join(out_dir_base, *java_package.split('.'))
     os.makedirs(sst_dir, exist_ok=True)
-    with open(os.path.join(sst_dir, java_class_name + '.java'), 'w') as f:
+    filename = os.path.join(sst_dir, java_class_name + '.java')
+
+    # Determine which line separator to use
+    if os.path.exists(filename):
+        with open(filename, "r", encoding="utf-8", newline=os.linesep) as f:
+            content = f.read()
+        if os.linesep != "\n":
+            if content.replace(os.linesep, "\n") == content:
+                # Windows file has Unix line endings
+                linesep = "\n"
+            else:
+                linesep = os.linesep
+        else:
+            linesep = "\n"
+    else:
+        linesep = os.linesep
+
+    with open(filename, 'w', encoding="utf-8", newline=linesep) as f:
         emitter = Emitter(f)
         f.write(HEADER)
         f.write(f'package {java_package};\n')

graalpython/com.oracle.graal.python.pegparser.generator/main_parser_gen.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# Copyright (c) 2021, 2022, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
 # DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 #
 # The Universal Permissive License (UPL), Version 1.0
@@ -69,10 +69,37 @@ def main():
     with open(args.tokens_file, "r") as tok_file:
         all_tokens, exact_tokens, non_exact_tokens = generate_token_definitions(tok_file)
 
-    with open(args.output_file, "w") as file:
+    # Determine which line separator to use
+    if os.path.exists(args.output_file):
+        stat_result = os.stat(args.output_file)
+        atime, mtime = stat_result.st_atime, stat_result.st_mtime
+        with open(args.output_file, "r", encoding="utf-8", newline=os.linesep) as f:
+            content = f.read()
+        if os.linesep != "\n":
+            unix_content = content.replace(os.linesep, "\n")
+            if unix_content == content:
+                # Windows file has Unix line endings
+                linesep = "\n"
+                content = unix_content
+            else:
+                linesep = os.linesep
+        else:
+            linesep = "\n"
+    else:
+        content = None
+        linesep = os.linesep
+
+    with open(args.output_file, "w", encoding="utf-8", newline=linesep) as file:
         gen = JavaParserGenerator(grammar, all_tokens, exact_tokens, non_exact_tokens, file, debug=args.debug)
         gen.generate(os.path.basename(args.grammar_file))
 
+    with open(args.output_file, "r", encoding="utf-8", newline=linesep) as file:
+        new_content = file.read()
+
+    if content == new_content:
+        print(f"{args.output_file} not modified")
+        os.utime(args.output_file, (atime, mtime))
+
 
 if __name__ == '__main__':
     main()