devel/py-setuptools_scm: Do not run "git archive" on Ports tree

* In build environments have git installed in conjunction with a
  git-based Ports tree and haven't WRKDIRPREFIX set, there will be
  significant delays when building devel/py-setuptools_scm or ports
  that depend on it.

  This is because the top-level directory of the git repository is
  determined during build via "git rev-parse --show-toplevel" which is
  issued inside the WRKSRC directory.

  Once the top-level directory (which is PORTSDIR) has been determined,
  an archive is created from this point using "git archive" which is
  then very time-consuming due the complexity of the Ports tree.

  In environments (e.g. poudriere) that have WRKDIRPREFIX set and also
  have git present during build, the issue doesn't appear because
  "git rev-parse --show-toplevel" fails silently with "not a git repo".

  Remedy the issue by returning only the actual path of WRKSRC, but only
  if it has "setup.py" in it (= devel/py-setuptools_scm is built) or a
  test session is performed.

* Modernize the "do-test" target while I'm here and bump PORTREVISION
  due package change.
PR:		258891
Reported by:	Robert Clausecker <fuz@fuz.su>
Obtained from:	OpenIndiana
MFH:		2021Q4 (after 1 week)

devel/py-setuptools_scm/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	setuptools_scm
 PORTVERSION=	4.1.2
-PORTREVISION=	2
+PORTREVISION=	3
 CATEGORIES=	devel python
 MASTER_SITES=	CHEESESHOP
 PKGNAMEPREFIX=	${PYTHON_PKGNAMEPREFIX}
@@ -19,6 +19,10 @@ TEST_DEPENDS=	${PYTHON_PKGNAMEPREFIX}pytest>0:devel/py-pytest@${PY_FLAVOR} \
 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
@@ -28,6 +32,6 @@ 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>

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

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