Configure `tox` to use `venv` (#12015)

As the comment says, virtualenv is a pile of fail.

3 files changed, 9 insertions, 1 deletions

diff --git a/.ci/scripts/test_old_deps.sh b/.ci/scripts/test_old_deps.sh

index 54ec3c8b0d..b2859f7522 100755
--- a/.ci/scripts/test_old_deps.sh
+++ b/.ci/scripts/test_old_deps.sh
@@ -8,7 +8,9 @@ export DEBIAN_FRONTEND=noninteractive
 set -ex
 
 apt-get update
-apt-get install -y python3 python3-dev python3-pip libxml2-dev libxslt-dev xmlsec1 zlib1g-dev tox libjpeg-dev libwebp-dev
+apt-get install -y \
+        python3 python3-dev python3-pip python3-venv \
+        libxml2-dev libxslt-dev xmlsec1 zlib1g-dev tox libjpeg-dev libwebp-dev
 
 export LANG="C.UTF-8"
 
diff --git a/changelog.d/12015.misc b/changelog.d/12015.misc
new file mode 100644

index 0000000000..3aa32ab4cf
--- /dev/null
+++ b/changelog.d/12015.misc
@@ -0,0 +1 @@
+Configure `tox` to use `venv` rather than `virtualenv`.
diff --git a/tox.ini b/tox.ini

index 32679e9106..2b3d39e034 100644
--- a/tox.ini
+++ b/tox.ini
@@ -4,6 +4,11 @@ envlist = packaging, py37, py38, py39, py310, check_codestyle, check_isort
 # we require tox>=2.3.2 for the fix to https://github.com/tox-dev/tox/issues/208
 minversion = 2.3.2
 
+# the tox-venv plugin makes tox use python's built-in `venv` module rather than
+# the legacy `virtualenv` tool. `virtualenv` embeds its own `pip`, `setuptools`,
+# etc, and ends up being rather unreliable.
+requires = tox-venv
+
 [base]
 deps =
     python-subunit