Sync release-tools

Sync release-tools boilerplate containing these changes
in order to pin pip < 20.3:
https://github.com/openstack-charmers/release-tools/pull/125
https://github.com/openstack-charmers/release-tools/pull/126

Change-Id: Ib977225e1dcb651dd9d98ab67edaa76545621451

requirements.txt

@@ -3,9 +3,24 @@
 # choices of *requirements.txt files for OpenStack Charms:
 #     https://github.com/openstack-charmers/release-tools
 #
+# NOTE(lourot): This might look like a duplication of test-requirements.txt but
+# some tox targets use only test-requirements.txt whereas charm-build uses only
+# requirements.txt
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
+
 # Build requirements
 charm-tools>=2.4.4
-# importlib-resources 1.1.0 removed Python 3.5 support
-importlib-resources<1.1.0
+
+# Workaround until https://github.com/juju/charm-tools/pull/589 gets
+# published
+keyring<21
+
 simplejson
+
+# Newer versions use keywords that didn't exist in python 3.5 yet (e.g.
+# "ModuleNotFoundError")
+# NOTE(lourot): This might look like a duplication of test-requirements.txt but
+# some tox targets use only test-requirements.txt whereas charm-build uses only
+# requirements.txt
+importlib-metadata<3.0.0; python_version < '3.6'
+importlib-resources<3.0.0; python_version < '3.6'

src/test-requirements.txt

@@ -3,6 +3,13 @@
 # choices of *requirements.txt files for OpenStack Charms:
 #     https://github.com/openstack-charmers/release-tools
 #
+# pep8 requirements
+charm-tools>=2.4.4
+
+# Workaround until https://github.com/juju/charm-tools/pull/589 gets
+# published
+keyring<21
+
 # Functional Test Requirements (let Zaza's dependencies solve all dependencies here!)
 git+https://github.com/openstack-charmers/zaza.git#egg=zaza
 git+https://github.com/openstack-charmers/zaza-openstack-tests.git#egg=zaza.openstack

src/tox.ini

@@ -11,6 +11,18 @@ skipsdist = True
 sitepackages = False
 # NOTE: Avoid false positives by not skipping missing interpreters.
 skip_missing_interpreters = False
+# NOTES:
+# * We avoid the new dependency resolver by pinning pip < 20.3, see
+#   https://github.com/pypa/pip/issues/9187
+# * Pinning dependencies requires tox >= 3.2.0, see
+#   https://tox.readthedocs.io/en/latest/config.html#conf-requires
+# * It is also necessary to pin virtualenv as a newer virtualenv would still
+#   lead to fetching the latest pip in the func* tox targets, see
+#   https://stackoverflow.com/a/38133283
+requires = pip < 20.3
+           virtualenv < 20.0
+# NOTE: https://wiki.canonical.com/engineering/OpenStack/InstallLatestToxOnOsci
+minversion = 3.2.0
 
 [testenv]
 setenv = VIRTUAL_ENV={envdir}
@@ -23,7 +35,6 @@ install_command =
 
 [testenv:pep8]
 basepython = python3
-deps=charm-tools
 commands = charm-proof
 
 [testenv:func-noop]

test-requirements.txt

@@ -6,10 +6,31 @@
 setuptools<50.0.0  # https://github.com/pypa/setuptools/commit/04e3df22df840c6bb244e9b27bc56750c44b7c85
 # Lint and unit test requirements
 flake8>=2.2.4
+
 stestr>=2.2.0
+
+# Dependency of stestr. Workaround for
+# https://github.com/mtreinish/stestr/issues/145
+cliff<3.0.0
+
+# Dependencies of stestr. Newer versions use keywords that didn't exist in
+# python 3.5 yet (e.g. "ModuleNotFoundError")
+importlib-metadata<3.0.0; python_version < '3.6'
+importlib-resources<3.0.0; python_version < '3.6'
+
+# Some Zuul nodes sometimes pull newer versions of these dependencies which
+# dropped support for python 3.5:
+osprofiler<2.7.0;python_version<'3.6'
+stevedore<1.31.0;python_version<'3.6'
+
 requests>=2.18.4
 charms.reactive
-mock>=1.2
+
+# Newer mock seems to have some syntax which is newer than python3.5 (e.g.
+# f'{something}'
+mock>=1.2,<4.0.0; python_version < '3.6'
+mock>=1.2; python_version >= '3.6'
+
 nose>=1.3.7
 coverage>=3.6
 git+https://github.com/openstack/charms.openstack.git#egg=charms.openstack