feat: allow explicit location to module

pybind11_stubgen/__init__.py

@@ -1,10 +1,13 @@
 from __future__ import annotations
 
 import importlib
+import importlib.util
 import logging
 import re
-from argparse import ArgumentParser, Namespace
+import sys
+from argparse import ArgumentParser, ArgumentTypeError, Namespace
 from pathlib import Path
+from types import ModuleType
 
 from pybind11_stubgen.parser.interface import IParser
 from pybind11_stubgen.parser.mixins.error_handlers import (
@@ -77,6 +80,7 @@ class CLIArgs(Namespace):
     dry_run: bool
     stub_extension: str
     module_name: str
+    location: Path | None
 
 
 def arg_parser() -> ArgumentParser:
@@ -215,6 +219,22 @@ def regex_colon_path(regex_path: str) -> tuple[re.Pattern, str]:
         "Must be 'pyi' (default) or 'py'",
     )
 
+    def existing_file(path: str) -> Path | None:
+        if path is None:
+            return None
+        try:
+            return Path(path).resolve(strict=True)
+        except FileNotFoundError:
+            raise ArgumentTypeError(f"Path {path!r} does not exist.")
+
+    parser.add_argument(
+        "--location",
+        type=existing_file,
+        default=None,
+        dest="location",
+        help="Explicit filesytem location for module",
+    )
+
     parser.add_argument(
         "module_name",
         metavar="MODULE_NAME",
@@ -324,6 +344,7 @@ def main():
         sub_dir=sub_dir,
         dry_run=args.dry_run,
         writer=Writer(stub_ext=args.stub_extension),
+        location=args.location,
     )
 
 
@@ -345,6 +366,16 @@ def to_output_and_subdir(
         return out_dir.joinpath(*module_path[:-1]), sub_dir
 
 
+def import_module_from_path(module_name: str, location: Path) -> ModuleType:
+    spec = importlib.util.spec_from_file_location(module_name, location)
+    if not (spec and spec.loader):
+        raise ImportError(f"Can't import {module_name} from {location}")
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    sys.modules[module_name] = module
+    return module
+
+
 def run(
     parser: IParser,
     printer: Printer,
@@ -353,10 +384,13 @@ def run(
     sub_dir: Path | None,
     dry_run: bool,
     writer: Writer,
+    location: Path | None,
 ):
-    module = parser.handle_module(
-        QualifiedName.from_str(module_name), importlib.import_module(module_name)
-    )
+    if location:
+        pymodule = import_module_from_path(module_name, location)
+    else:
+        pymodule = importlib.import_module(module_name)
+    module = parser.handle_module(QualifiedName.from_str(module_name), pymodule)
     parser.finalize()
 
     if module is None: