From 27b427e89438b398649acff651e0120add69db3b Mon Sep 17 00:00:00 2001
From: Abderrahim Kitouni <akitouni@gnome.org>
Date: Wed, 15 Dec 2021 15:38:54 +0100
Subject: [PATCH 1/3] setup.py: support pure-python cython extensions

---
 setup.py | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/setup.py b/setup.py
index 3f48e0d9a..013842e82 100755
--- a/setup.py
+++ b/setup.py
@@ -253,12 +253,15 @@ def cythonize(extensions, **kwargs):
         missing_c_sources = []
 
         for extension in extensions:
+            c_sources = []
             for source in extension.sources:
-                if source.endswith(".pyx"):
-                    c_file = source.replace(".pyx", ".c")
+                if source.endswith(".pyx") or source.endswith(".py"):
+                    c_file = source.replace(".pyx", ".c").replace(".py", ".c")
+                    c_sources.append(c_file)
 
                     if not os.path.exists(c_file):
                         missing_c_sources.append((extension, c_file))
+            extension.sources = c_sources
 
         if missing_c_sources:
             for extension, source in missing_c_sources:
@@ -273,29 +276,29 @@ def cythonize(extensions, **kwargs):
 def register_cython_module(module_name, dependencies=None):
     def files_from_module(modname):
         basename = "src/{}".format(modname.replace(".", "/"))
+        if os.path.exists("{}.py".format(basename)):
+            return ("{}.py".format(basename),)
         return "{}.pyx".format(basename), "{}.pxd".format(basename)
 
     if dependencies is None:
         dependencies = []
 
-    implementation_file, definition_file = files_from_module(module_name)
+    cython_files = files_from_module(module_name)
 
-    assert os.path.exists(implementation_file)
+    assert os.path.exists(cython_files[0])
 
     depends = []
-    if os.path.exists(definition_file):
-        depends.append(definition_file)
+    if len(cython_files) == 2 and os.path.exists(cython_files[1]):
+        depends.append(cython_files[1])
 
     for module in dependencies:
-        imp_file, def_file = files_from_module(module)
-        assert os.path.exists(imp_file), "Dependency file not found: {}".format(imp_file)
-        assert os.path.exists(def_file), "Dependency declaration file not found: {}".format(def_file)
+        files = files_from_module(module)
+        assert all(os.path.exists(f) for f in files), "Missing file for module: {}".format(module)
 
-        depends.append(imp_file)
-        depends.append(def_file)
+        depends.extend(files)
 
     BUILD_EXTENSIONS.append(
-        Extension(name=module_name, sources=[implementation_file], depends=depends, define_macros=extension_macros,)
+        Extension(name=module_name, sources=[cython_files[0]], depends=depends, define_macros=extension_macros,)
     )
 
 

From fe685c51b8349af3c2c6ec90ed9f8dc900e686f1 Mon Sep 17 00:00:00 2001
From: Abderrahim Kitouni <akitouni@gnome.org>
Date: Wed, 15 Dec 2021 15:49:28 +0100
Subject: [PATCH 2/3] _types.py: compile as a pure-python module

Fix lint and formatting errors in the process
---
 src/buildstream/{_types.pyx => _types.py} | 15 ++++++++-------
 src/buildstream/_types.pyi                |  1 -
 2 files changed, 8 insertions(+), 8 deletions(-)
 rename src/buildstream/{_types.pyx => _types.py} (91%)
 delete mode 100644 src/buildstream/_types.pyi

diff --git a/src/buildstream/_types.pyx b/src/buildstream/_types.py
similarity index 91%
rename from src/buildstream/_types.pyx
rename to src/buildstream/_types.py
index ac65c505c..62a3ee011 100644
--- a/src/buildstream/_types.pyx
+++ b/src/buildstream/_types.py
@@ -58,8 +58,9 @@ def set_values(mcs, kls, data):
         value_to_entry = {}
 
         assert len(set(data.values())) == len(data.values()), "Values for {} are not unique".format(kls)
-        assert len(set(type(value) for value in data.values())) <= 1, \
-            "Values of {} are of heterogeneous types".format(kls)
+        assert len(set(type(value) for value in data.values())) <= 1, "Values of {} are of heterogeneous types".format(
+            kls
+        )
 
         for key, value in data.items():
             new_value = object.__new__(kls)
@@ -72,11 +73,11 @@ def set_values(mcs, kls, data):
 
         type.__setattr__(kls, "_value_to_entry", value_to_entry)
 
-    def __repr__(self):
-        return "<fastenum '{}'>".format(self.__name__)
+    def __repr__(cls):
+        return "<fastenum '{}'>".format(cls.__name__)
 
-    def __setattr__(self, key, value):
+    def __setattr__(cls, key, value):
         raise AttributeError("Adding new values dynamically is not supported")
 
-    def __iter__(self):
-        return iter(self._value_to_entry.values())
+    def __iter__(cls):
+        return iter(cls._value_to_entry.values())
diff --git a/src/buildstream/_types.pyi b/src/buildstream/_types.pyi
deleted file mode 100644
index d1986fc4a..000000000
--- a/src/buildstream/_types.pyi
+++ /dev/null
@@ -1 +0,0 @@
-class MetaFastEnum(type): ...

From 36e7d5d5b2899d43a7a4610913a00fe1d1419fdc Mon Sep 17 00:00:00 2001
From: Abderrahim Kitouni <akitouni@gnome.org>
Date: Wed, 15 Dec 2021 19:53:12 +0100
Subject: [PATCH 3/3] _utils.py: port to pure-python syntax

Fix lint and formatting errors in the process
---
 pyproject.toml                            |  2 +-
 setup.cfg                                 |  2 +-
 src/buildstream/{_utils.pyx => _utils.py} | 23 ++++++++++++-----------
 src/buildstream/_utils.pyi                |  3 ---
 4 files changed, 14 insertions(+), 16 deletions(-)
 rename src/buildstream/{_utils.pyx => _utils.py} (81%)
 delete mode 100644 src/buildstream/_utils.pyi

diff --git a/pyproject.toml b/pyproject.toml
index fefbbecd4..8afddd6f6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ requires = [
     "setuptools>=36.6.0",
     # In order to build wheels, and as required by PEP 517
     "wheel",
-    "Cython"
+    "Cython>=3a"
 ]
 build-backend = "setuptools.build_meta"
 
diff --git a/setup.cfg b/setup.cfg
index 283d78099..b6817e7e6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -28,7 +28,7 @@ warn_no_return = True
 
 # Ignore missing stubs for third-party packages.
 # In future, these should be re-enabled if/when stubs for them become available.
-[mypy-copyreg,grpc,pluginbase,psutil,pyroaring,ruamel,multiprocessing.forkserver]
+[mypy-copyreg,grpc,pluginbase,psutil,pyroaring,ruamel,multiprocessing.forkserver,cython.*]
 ignore_missing_imports=True
 
 # Ignore issues with generated files and vendored code
diff --git a/src/buildstream/_utils.pyx b/src/buildstream/_utils.py
similarity index 81%
rename from src/buildstream/_utils.pyx
rename to src/buildstream/_utils.py
index 2386ef430..4b99ef25c 100644
--- a/src/buildstream/_utils.pyx
+++ b/src/buildstream/_utils.py
@@ -22,12 +22,13 @@
 This module contains utilities that have been optimized in Cython
 """
 
-from cpython.pystate cimport PyThreadState_SetAsyncExc
-from cpython.ref cimport PyObject
+import cython  # pylint: disable=import-error
+from cython.cimports.cpython.pystate import PyThreadState_SetAsyncExc  # pylint: disable=import-error
+from cython.cimports.cpython.ref import PyObject  # pylint: disable=import-error
 from ._signals import TerminateException
 
 
-def url_directory_name(str url):
+def url_directory_name(url: str):
     """Normalizes a url into a directory name
 
     Args:
@@ -36,8 +37,7 @@ def url_directory_name(str url):
     Returns:
        A string which can be used as a directory name
     """
-    return ''.join([_transl(x) for x in url])
-
+    return "".join([_transl(x) for x in url])
 
 
 # terminate_thread()
@@ -47,8 +47,8 @@ def url_directory_name(str url):
 # Args:
 #   thread_id (int): the thread id in which to throw the exception
 #
-def terminate_thread(long thread_id):
-    res = PyThreadState_SetAsyncExc(thread_id, <PyObject*> TerminateException)
+def terminate_thread(thread_id: cython.long):
+    res = PyThreadState_SetAsyncExc(thread_id, cython.cast(cython.pointer(PyObject), TerminateException))
     assert res == 1
 
 
@@ -60,9 +60,9 @@ def terminate_thread(long thread_id):
 # Returns:
 #    (bool): True if all characters are valid, False otherwise.
 #
-def valid_chars_name(str name):
-    cdef int char_value
-    cdef int forbidden_char
+def valid_chars_name(name: str):
+    char_value: cython.int
+    forbidden_char: cython.int
 
     for char_value in name:
         # 0-31 are control chars, 127 is DEL, and >127 means non-ASCII
@@ -96,7 +96,8 @@ def valid_chars_name(str name):
 #
 # This transforms the value to "_" if is it not a ascii letter, a digit or "%" or "_"
 #
-cdef Py_UNICODE _transl(Py_UNICODE x):
+@cython.cfunc
+def _transl(x: cython.Py_UNICODE) -> cython.Py_UNICODE:
     if ("a" <= x <= "z") or ("A" <= x <= "Z") or ("0" <= x <= "9") or x == "%":
         return x
     return "_"
diff --git a/src/buildstream/_utils.pyi b/src/buildstream/_utils.pyi
deleted file mode 100644
index 1938eec08..000000000
--- a/src/buildstream/_utils.pyi
+++ /dev/null
@@ -1,3 +0,0 @@
-def url_directory_name(url: str) -> str: ...
-def valid_chars_name(name: str) -> bool: ...
-def terminate_thread(thread_id: int) -> None: ...