diff -r 75a13d812a10 -r e1f53a68b146 debian/rules
--- a/debian/rules	Sat Oct 05 13:50:13 2019 -0400
+++ b/debian/rules	Mon Dec 09 23:54:50 2019 +0100
@@ -2,12 +2,14 @@
 #export DH_VERBOSE=1
 
 %:
-	dh $@ --with python2 --buildsystem=python_distutils
+	dh $@ --with python2,python3,sphinxdoc --buildsystem=pybuild
 
+ifeq (,$(filter nodoc, $(DEB_BUILD_OPTIONS)))
 override_dh_auto_build:
 	dh_auto_build
 	# Workaround for Sphinx in Debian Buster defaulting to Python 3
 	SPHINXBUILD="python -m sphinx -bhtml" $(MAKE) -C docs
+endif
 
 hgsrc_defined:
 	# Use "! -z" instead of "-n", because "-n" without arguments is true
@@ -23,6 +25,11 @@
 	find debian -path '*/hgext3rd/__init__.py' -delete
 	dh_python2
 
+override_dh_python3:
+	# avoid conflict with mercurial's own hgext3rd/__init__.py
+	find debian -path '*/hgext3rd/__init__.py' -delete
+	dh_python3
+
 override_dh_auto_clean: clean-docs
 	dh_auto_clean
 	rm -f tests/*.err