Python: Drop support for Python 3.6

Python 3.6 was EOL 2021-12-31. Newer versions of upstream libraries have
begun dropping support for this version and it is becoming more
cumbersome to support. Avocado-framework and qemu.qmp each have their
own reasons for wanting to drop Python 3.6, but won't until QEMU does.

Versions of Python available in our supported build platforms as of today,
with optional versions available in parentheses:

openSUSE Leap 15.4: 3.6.15 (3.9.10, 3.10.2)
CentOS Stream 8:    3.6.8  (3.8.13, 3.9.16)
CentOS Stream 9:    3.9.13
Fedora 36:          3.10
Fedora 37:          3.11
Debian 11:          3.9.2
Alpine 3.14, 3.15:  3.9.16
Alpine 3.16, 3.17:  3.10.10
Ubuntu 20.04 LTS:   3.8.10
Ubuntu 22.04 LTS:   3.10.4
NetBSD 9.3:         3.9.13*
FreeBSD 12.4:       3.9.16
FreeBSD 13.1:       3.9.16
OpenBSD 7.2:        3.9.16

Note: Our VM tests install 3.9 explicitly for FreeBSD and 3.10 for
NetBSD; the default for "python" or "python3" in FreeBSD is
3.9.16. NetBSD does not appear to have a default meta-package, but
offers several options, the lowest of which is 3.7.15. "python39"
appears to be a pre-requisite to one of the other packages we request in
tests/vm/netbsd. pip, ensurepip and other Python essentials are
currently only available for Python 3.10 for NetBSD.

CentOS and OpenSUSE support parallel installation of multiple Python
interpreters, and binaries in /usr/bin will always use Python 3.6.  However,
the newly introduced support for virtual environments ensures that all build
steps that execute QEMU Python code use a single interpreter.

Since it is safe to under our supported platform policy, bump our
minimum supported version of Python to 3.7.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20230511035435.734312-24-jsnow@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 9 insertions, 10 deletions

diff --git a/python/Makefile b/python/Makefile
index 47560657d2..7c70dcc8d1 100644
--- a/python/Makefile
+++ b/python/Makefile
@@ -9,14 +9,14 @@ help:
 	@echo "make check-minreqs:"
 	@echo "    Run tests in the minreqs virtual environment."
 	@echo "    These tests use the oldest dependencies."
-	@echo "    Requires: Python 3.6"
-	@echo "    Hint (Fedora): 'sudo dnf install python3.6'"
+	@echo "    Requires: Python 3.7"
+	@echo "    Hint (Fedora): 'sudo dnf install python3.7'"
 	@echo ""
 	@echo "make check-tox:"
 	@echo "    Run tests against multiple python versions."
 	@echo "    These tests use the newest dependencies."
-	@echo "    Requires: Python 3.6 - 3.10, and tox."
-	@echo "    Hint (Fedora): 'sudo dnf install python3-tox python3.10'"
+	@echo "    Requires: Python 3.7 - 3.11, and tox."
+	@echo "    Hint (Fedora): 'sudo dnf install python3-tox python3.11'"
 	@echo "    The variable QEMU_TOX_EXTRA_ARGS can be use to pass extra"
 	@echo "    arguments to tox".
 	@echo ""
@@ -59,7 +59,7 @@ PIP_INSTALL = pip install --disable-pip-version-check
 min-venv: $(QEMU_MINVENV_DIR) $(QEMU_MINVENV_DIR)/bin/activate
 $(QEMU_MINVENV_DIR) $(QEMU_MINVENV_DIR)/bin/activate: setup.cfg tests/minreqs.txt
 	@echo "VENV $(QEMU_MINVENV_DIR)"
-	@python3.6 -m venv $(QEMU_MINVENV_DIR)
+	@python3.7 -m venv $(QEMU_MINVENV_DIR)
 	@(								\
 		echo "ACTIVATE $(QEMU_MINVENV_DIR)";			\
 		. $(QEMU_MINVENV_DIR)/bin/activate;			\
diff --git a/python/setup.cfg b/python/setup.cfg
index fc3fae5b10..55c0993e70 100644
--- a/python/setup.cfg
+++ b/python/setup.cfg
@@ -14,7 +14,6 @@ classifiers =
     Natural Language :: English
     Operating System :: OS Independent
     Programming Language :: Python :: 3 :: Only
-    Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
     Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
@@ -23,7 +22,7 @@ classifiers =
     Typing :: Typed
 
 [options]
-python_requires = >= 3.6
+python_requires = >= 3.7
 packages =
     qemu.qmp
     qemu.machine
@@ -77,7 +76,7 @@ exclude = __pycache__,
 
 [mypy]
 strict = True
-python_version = 3.6
+python_version = 3.7
 warn_unused_configs = True
 namespace_packages = True
 warn_unused_ignores = False
@@ -199,7 +198,7 @@ multi_line_output=3
 # of python available on your system to run this test.
 
 [tox:tox]
-envlist = py36, py37, py38, py39, py310, py311
+envlist = py37, py38, py39, py310, py311
 skip_missing_interpreters = true
 
 [testenv]
diff --git a/python/tests/minreqs.txt b/python/tests/minreqs.txt
index 7ecf5e7fe4..10b181d43a 100644
--- a/python/tests/minreqs.txt
+++ b/python/tests/minreqs.txt
@@ -1,5 +1,5 @@
 # This file lists the ***oldest possible dependencies*** needed to run
-# "make check" successfully under ***Python 3.6***. It is used primarily
+# "make check" successfully under ***Python 3.7***. It is used primarily
 # by GitLab CI to ensure that our stated minimum versions in setup.cfg
 # are truthful and regularly validated.
 #