Use custom build backend for the client package

client/build_backend/backend.py

@@ -0,0 +1,62 @@
+import sys
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+from setuptools import build_meta as _orig
+from setuptools.build_meta import *  # noqa: F403
+
+
+def gen_types_if_needed() -> None:
+    tl_root = Path("src/telethon/_impl/tl")
+    layer_py = tl_root / "layer.py"
+    mtproto_root = tl_root / "mtproto"
+
+    generator_path = "../generator/src"
+    api_tl = Path("../generator/tl/api.tl")
+    mtproto_tl = Path("../generator/tl/mtproto.tl")
+
+    if not layer_py.exists():
+        print(layer_py, "is missing; attempting to generate types", file=sys.stderr)
+
+        # Import generator and clean-up path
+        sys.path.append(generator_path)
+        import telethon_generator as gen
+
+        sys.path.remove(generator_path)
+
+        # api.tl
+        fs = gen.codegen.FakeFs()
+        gen.codegen.generate(fs, gen.tl_parser.load_tl_file(api_tl))
+        fs.materialize(tl_root)
+        print("written api.tl files:", tl_root, file=sys.stderr)
+
+        # mtproto.tl
+        fs = gen.codegen.FakeFs()
+        gen.codegen.generate(fs, gen.tl_parser.load_tl_file(mtproto_tl))
+        fs.materialize(mtproto_root)
+        print("written mtproto.tl files:", mtproto_root, file=sys.stderr)
+
+
+def build_wheel(  # type: ignore [no-redef]
+    wheel_directory: str,
+    config_settings: Optional[Dict[Any, Any]] = None,
+    metadata_directory: Optional[str] = None,
+) -> str:
+    gen_types_if_needed()
+    return _orig.build_wheel(wheel_directory, config_settings, metadata_directory)
+
+
+def build_sdist(  # type: ignore [no-redef]
+    sdist_directory: str, config_settings: Optional[Dict[Any, Any]] = None
+) -> str:
+    gen_types_if_needed()
+    return _orig.build_sdist(sdist_directory, config_settings)
+
+
+def build_editable(  # type: ignore [no-redef]
+    wheel_directory: str,
+    config_settings: Optional[Dict[Any, Any]] = None,
+    metadata_directory: Optional[str] = None,
+) -> str:
+    gen_types_if_needed()
+    return _orig.build_editable(wheel_directory, config_settings, metadata_directory)

client/pyproject.toml

@@ -48,7 +48,8 @@ doc = [
 
 [build-system]
 requires = ["setuptools>=61.0"]
-build-backend = "setuptools.build_meta"
+build-backend = "backend"
+backend-path = ["build_backend"]
 
 [tool.setuptools.dynamic]
 version = {attr = "telethon.version.__version__"}

stubs/setuptools.build_meta.pyi

@@ -0,0 +1,15 @@
+from typing import Any, Dict, Optional
+
+def build_wheel(
+    wheel_directory: str,
+    config_settings: Optional[Dict[Any, Any]] = None,
+    metadata_directory: Optional[str] = None,
+) -> str: ...
+def build_sdist(
+    sdist_directory: str, config_settings: Optional[Dict[Any, Any]] = None
+) -> str: ...
+def build_editable(
+    wheel_directory: str,
+    config_settings: Optional[Dict[Any, Any]] = None,
+    metadata_directory: Optional[str] = None,
+) -> str: ...