[python] don't overwrite version.py file if existing version is higher (microsoft#5559)

fixes microsoft#5528, microsoft#5529

---------

Co-authored-by: iscai-msft <[email protected]>
Co-authored-by: Yuchao Yan <[email protected]>

Author: 3 people

packages/http-client-python/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Change Log - @typespec/http-client-python
 
+## 0.6.2
+
+### Bug Fixes
+
+- Don't automatically overwrite version in `_version.py` file and `setup.py` file if the existing version is newer
+
 ## 0.6.1
 
 ### Bug Fixes

packages/http-client-python/generator/pygen/codegen/serializers/__init__.py

@@ -5,6 +5,7 @@
 # --------------------------------------------------------------------------
 import logging
 from collections import namedtuple
+import re
 from typing import List, Any, Union
 from pathlib import Path
 from jinja2 import PackageLoader, Environment, FileSystemLoader, StrictUndefined
@@ -94,6 +95,19 @@ def serialize_loop(self) -> List[AsyncInfo]:
         async_loop = AsyncInfo(async_mode=True, async_path="aio/")
         return [sync_loop, async_loop] if self.has_aio_folder else [sync_loop]
 
+    @property
+    def keep_version_file(self) -> bool:
+        if self.options.get("keep_version_file"):
+            return True
+        # If the version file is already there and the version is greater than the current version, keep it.
+        try:
+            serialized_version_file = self.read_file(self.exec_path(self.code_model.namespace) / "_version.py")
+            match = re.search(r'VERSION\s*=\s*"([^"]+)"', str(serialized_version_file))
+            serialized_version = match.group(1) if match else ""
+        except (FileNotFoundError, IndexError):
+            serialized_version = ""
+        return serialized_version > self.code_model.options["package_version"]
+
     def serialize(self) -> None:
         env = Environment(
             loader=PackageLoader("pygen.codegen", "templates"),
@@ -193,6 +207,9 @@ def _serialize_and_write_package_files(self, client_namespace: str) -> None:
             file = template_name.replace(".jinja2", "")
             output_name = root_of_sdk / file
             if not self.read_file(output_name) or file in _REGENERATE_FILES:
+                if self.keep_version_file and file == "setup.py":
+                    # don't regenerate setup.py file if the version file is more up to date
+                    continue
                 self.write_file(
                     output_name,
                     serializer.serialize_package_file(template_name, **params),
@@ -329,10 +346,9 @@ def _write_version_file(original_version_file_name: str) -> None:
                 _read_version_file(original_version_file_name),
             )
 
-        keep_version_file = self.code_model.options["keep_version_file"]
-        if keep_version_file and _read_version_file("_version.py"):
+        if self.keep_version_file and _read_version_file("_version.py"):
             _write_version_file(original_version_file_name="_version.py")
-        elif keep_version_file and _read_version_file("version.py"):
+        elif self.keep_version_file and _read_version_file("version.py"):
             _write_version_file(original_version_file_name="version.py")
         elif self.code_model.options["package_version"]:
             self.write_file(

packages/http-client-python/package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@typespec/http-client-python",
-  "version": "0.6.1",
+  "version": "0.6.2",
   "author": "Microsoft Corporation",
   "description": "TypeSpec emitter for Python SDKs",
   "homepage": "https://typespec.io",