Fix crash when installing extension

Author: Rongronggg9

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## Unreleased
+### Fixed
+- Fix regression in `install_extension` crashing since 1.8.0. [#380](https://github.com/PyO3/setuptools-rust/pull/380)
+
 ## 1.8.0 (2023-10-26)
 ### Packaging
 - Drop support for Python 3.7. [#357](https://github.com/PyO3/setuptools-rust/pull/357)

setuptools_rust/build.py

@@ -372,6 +372,8 @@ def install_extension(
                 # will install the rust library into the module directory
                 ext_path = self.get_dylib_ext_path(ext, module_name)
 
+            os.makedirs(os.path.dirname(ext_path), exist_ok=True)
+
             # Make filenames relative to cwd where possible, to make logs and
             # errors below a little neater
 
@@ -381,7 +383,6 @@ def install_extension(
             if ext_path.startswith(cwd):
                 ext_path = os.path.relpath(ext_path, cwd)
 
-            os.makedirs(os.path.dirname(ext_path), exist_ok=True)
             logger.info("Copying rust artifact from %s to %s", dylib_path, ext_path)
 
             # We want to atomically replace any existing library file. We can't