diff --git a/devel/py-setuptools_scm/Makefile b/devel/py-setuptools_scm/Makefile
index 6d5f80cc6d07..c3a15793cfb0 100644
--- a/devel/py-setuptools_scm/Makefile
+++ b/devel/py-setuptools_scm/Makefile
@@ -1,33 +1,37 @@
 PORTNAME=	setuptools_scm
 PORTVERSION=	4.1.2
-PORTREVISION=	2
+PORTREVISION=	3
 CATEGORIES=	devel python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
 
 MAINTAINER=	kai@FreeBSD.org
 COMMENT=	Setuptools plugin to manage your versions by scm tags
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 TEST_DEPENDS=	${PYTHON_PKGNAMEPREFIX}pytest>0:devel/py-pytest@${PY_FLAVOR} \
 		${PYTHON_PKGNAMEPREFIX}pip>0:devel/py-pip@${PY_FLAVOR} \
 		git:devel/git \
 		${PY_MERCURIAL}
 
 USES=		python:3.6+
 USE_PYTHON=	autoplist distutils
 
+# Workaround to get a 100% working test suite.  This can be removed once
+# https://github.com/pypa/setuptools_scm/issues/353 is solved.
+TEST_ENV=	_PYTEST_SESSION=yes
+
 NO_ARCH=	yes
 
 OPTIONS_DEFINE=		TOML
 OPTIONS_DEFAULT=	TOML
 
 TOML_DESC=		Support for parsing pyproject.toml files [PEP 517/518]
 TOML_RUN_DEPENDS=	${PYTHON_PKGNAMEPREFIX}toml>0:textproc/py-toml@${PY_FLAVOR}
 
 do-test:
-	@cd ${WRKSRC} && ${PYTHON_CMD} -m pytest -v -rs
+	@cd ${TEST_WRKSRC} && ${SETENV} ${TEST_ENV} ${PYTHON_CMD} -m pytest -v -rs
 
 .include <bsd.port.mk>
diff --git a/devel/py-setuptools_scm/files/patch-src_setuptools__scm_file__finder__git.py b/devel/py-setuptools_scm/files/patch-src_setuptools__scm_file__finder__git.py
new file mode 100644
index 000000000000..d33a125106b5
--- /dev/null
+++ b/devel/py-setuptools_scm/files/patch-src_setuptools__scm_file__finder__git.py
@@ -0,0 +1,22 @@
+Workaround for https://github.com/pypa/setuptools_scm/issues/353
+
+Original version (without the check for test sessions) obtained from:
+
+https://github.com/OpenIndiana/oi-userland/commit/7d928fa26c0c5e4c29b4826fe78dc42401730529
+
+--- src/setuptools_scm/file_finder_git.py.orig	2021-10-20 09:27:26 UTC
++++ src/setuptools_scm/file_finder_git.py
+@@ -18,7 +18,12 @@ def _git_toplevel(path):
+                 stderr=devnull,
+             )
+         trace("find files toplevel", out)
+-        return os.path.normcase(os.path.realpath(out.strip()))
++        toplevel_path = os.path.normcase(os.path.realpath(out.strip()))
++        setup_py_path = os.path.join(toplevel_path, "setup.py")
++        if os.path.exists(setup_py_path) or os.environ.get("_PYTEST_SESSION"):
++            return toplevel_path
++        else:
++            return None
+     except subprocess.CalledProcessError:
+         # git returned error, we are not in a git repo
+         return None
diff --git a/devel/py-setuptools_scm/files/patch-src_setuptools__scm_file__finder__hg.py b/devel/py-setuptools_scm/files/patch-src_setuptools__scm_file__finder__hg.py
new file mode 100644
index 000000000000..7da5458d484a
--- /dev/null
+++ b/devel/py-setuptools_scm/files/patch-src_setuptools__scm_file__finder__hg.py
@@ -0,0 +1,22 @@
+Workaround for https://github.com/pypa/setuptools_scm/issues/353
+
+Original version (without the check for test sessions) obtained from:
+
+https://github.com/OpenIndiana/oi-userland/commit/7d928fa26c0c5e4c29b4826fe78dc42401730529
+
+--- src/setuptools_scm/file_finder_hg.py.orig	2021-10-20 09:29:52 UTC
++++ src/setuptools_scm/file_finder_hg.py
+@@ -13,7 +13,12 @@ def _hg_toplevel(path):
+                 universal_newlines=True,
+                 stderr=devnull,
+             )
+-        return os.path.normcase(os.path.realpath(out.strip()))
++        toplevel_path = os.path.normcase(os.path.realpath(out.strip()))
++        setup_py_path = os.path.join(toplevel_path, "setup.py")
++        if os.path.exists(setup_py_path) or os.environ.get("_PYTEST_SESSION"):
++            return toplevel_path
++        else:
++            return None
+     except subprocess.CalledProcessError:
+         # hg returned error, we are not in a mercurial repo
+         return None