diff --git a/var/spack/repos/builtin/packages/py-archspec/package.py b/var/spack/repos/builtin/packages/py-archspec/package.py
index ac9b3d3cce..2451ffe012 100644
--- a/var/spack/repos/builtin/packages/py-archspec/package.py
+++ b/var/spack/repos/builtin/packages/py-archspec/package.py
@@ -30,7 +30,7 @@ class PyArchspec(PythonPackage):
 
     def patch(self):
         # See https://python-poetry.org/docs/pyproject/#poetry-and-pep-517
-        with working_dir(self.build_directory):
+        with working_dir(self.stage.source_path):
             if self.spec.satisfies("@:0.1.3"):
                 filter_file("poetry>=0.12", "poetry_core>=1.0.0", "pyproject.toml")
                 filter_file("poetry.masonry.api", "poetry.core.masonry.api", "pyproject.toml")