Bump minimum python version to 3.9 (#6167)

* dropped 3.7 support

* Update setup.py

* Removed 3.8 as well

* changing some more 3.8's to 3.9's

* reformat

* Update pyproject.toml

* Update setup.py

* changing notebook python versions

* Update setup.py

* testing

* Update packaging_test.sh

* Update packaging_test.sh

* Update packaging_test.sh

* adding 311

* updating formatter

* Bump Python version for CI actions to 3.9

* Remove code specific to Python <= 3.8 only

* Drop redundant python_version checks from requirement files

* Fix required Python version in the installation doc

* Clean redundant assertion

* Skip coverage for code run in subprocess

* Suggest a more recent cirq for old pythons

---------

Co-authored-by: Pavol Juhas <juhas@google.com>

.github/workflows/ci-weekly.yml

@@ -23,7 +23,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: pip install -r dev_tools/requirements/isolated-base.env.txt

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Misc
         run: check/misc
@@ -31,7 +31,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.7'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install dependencies
         run: pip install -r dev_tools/requirements/deps/packaging.txt
@@ -46,7 +46,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install dependencies
         run: pip install -r dev_tools/requirements/deps/format.txt
@@ -59,7 +59,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install mypy
         run: pip install -r dev_tools/requirements/mypy.env.txt
@@ -74,7 +74,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install changed files test dependencies
         run: dev_tools/conf/pip-install-minimal-for-pytest-changed-files.sh
@@ -87,7 +87,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install pylint
         run: pip install -r dev_tools/requirements/pylint.env.txt
@@ -102,7 +102,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: pip install -r dev_tools/requirements/dev.env.txt
@@ -117,7 +117,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: pip install -r dev_tools/requirements/deps/tensorflow-docs.txt
@@ -139,7 +139,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install dependencies
         run: pip install -r dev_tools/requirements/isolated-base.env.txt
@@ -149,7 +149,7 @@ jobs:
     name: Pytest Ubuntu
     strategy:
       matrix:
-        python-version: [ '3.7', '3.8', '3.9', '3.10' ]
+        python-version: [ '3.9', '3.10' ]
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v3
@@ -178,7 +178,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: pip install pip-tools
@@ -192,7 +192,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: |
@@ -208,7 +208,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: |
@@ -224,7 +224,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - uses: actions/cache@v2
         with:
@@ -244,7 +244,7 @@ jobs:
     name: Pytest Windows
     strategy:
       matrix:
-        python-version: [ '3.7', '3.8', '3.9', '3.10' ]
+        python-version: [ '3.9', '3.10' ]
     runs-on: windows-2019
     steps:
       - uses: actions/checkout@v3
@@ -269,7 +269,7 @@ jobs:
     name: Pytest MacOS
     strategy:
       matrix:
-        python-version: [ '3.7.16', '3.8', '3.9', '3.10' ]
+        python-version: [ '3.9', '3.10' ]
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v3
@@ -302,7 +302,7 @@ jobs:
           fetch-depth: 0
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: pip install -r dev_tools/requirements/isolated-base.env.txt
@@ -320,7 +320,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install requirements
         run: pip install -r dev_tools/requirements/notebooks.env.txt

.github/workflows/release-master.yml

@@ -15,7 +15,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-python@v4
         with:
-          python-version: '3.8'
+          python-version: '3.9'
           architecture: 'x64'
       - name: Install dependencies
         run: |

.readthedocs.yml

@@ -2,7 +2,7 @@ version: 2
 build:
   image: latest
 python:
-  version: 3.8
+  version: 3.9
   install:
       - requirements: rtd_docs/requirements.txt
 sphinx:

Dockerfile

@@ -1,4 +1,4 @@
-FROM python:3.8-slim AS cirq_base
+FROM python:3.9-slim AS cirq_base
 
 # Install dependencies.
 # rm -rf /var/lib/apt/lists/* cleans up apt cache. See https://docs.docker.com/develop/develop-images/dockerfile_best-practices/

asv.conf.json

@@ -8,7 +8,7 @@
     "dvcs": "git",
     "environment_type": "virtualenv",
     "show_commit_url": "https://github.com/quantumlib/Cirq/commit/",
-    "pythons": ["3.8"],
+    "pythons": ["3.9"],
     "matrix": {"env_nobuild": {"PYTHONOPTIMIZE": ["-O", ""]}},
     "benchmark_dir": "benchmarks",
     "env_dir": ".asv/env",

benchmarks/README.md

@@ -13,7 +13,7 @@ To run all benchmarks, navigate to the root Cirq directory at the command line a
 
 You can also pass arguments to the script, which would be forwarded to the `asv run` command. For eg:
 ```bash
-./check/asv_run --quick --bench bench_examples --python 3.8
+./check/asv_run --quick --bench bench_examples --python 3.9
 ```
 
 Please refer [Running Benchmarks guide by ASV](https://asv.readthedocs.io/en/stable/using.html#running-benchmarks) for more information. 

cirq-aqt/setup.py

@@ -60,7 +60,7 @@
     url='http://github.com/quantumlib/cirq',
     author='The Cirq Developers',
     author_email='cirq-dev@googlegroups.com',
-    python_requires=('>=3.7.0'),
+    python_requires=('>=3.9.0'),
     install_requires=requirements,
     license='Apache 2',
     description=description,

cirq-core/cirq/_compat_test.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 import collections
 import dataclasses
-import importlib
+import importlib.metadata
 import logging
 import multiprocessing
 import os
@@ -722,21 +722,12 @@ def test_metadata_search_path():
     subprocess_context(_test_metadata_search_path_inner)()
 
 
-def _test_metadata_search_path_inner():
+def _test_metadata_search_path_inner():  # pragma: no cover
     # initialize the DeprecatedModuleFinders
     # pylint: disable=unused-import
     import cirq.testing._compat_test_data.module_a
 
-    try:
-        # importlib.metadata for python 3.8+
-        # coverage: ignore
-        import importlib.metadata as m
-    except:  # coverage: ignore
-        # coverage: ignore
-        # importlib_metadata for python <3.8
-        m = pytest.importorskip("importlib_metadata")
-
-    assert m.metadata('flynt')
+    assert importlib.metadata.metadata('flynt')
 
 
 def test_metadata_distributions_after_deprecated_submodule():

cirq-core/cirq/_version.py

@@ -13,20 +13,20 @@
 # limitations under the License.
 
 """Define version number here, read it from setup.py automatically,
-and warn users that the latest version of cirq uses python 3.7+"""
+and warn users that the latest version of cirq uses python 3.9+"""
 
 import sys
 
-if sys.version_info < (3, 7, 0):
+if sys.version_info < (3, 9, 0):
     # coverage: ignore
     raise SystemError(
-        "You installed the latest version of cirq but aren't on python 3.7+.\n"
+        "You installed the latest version of cirq but aren't on python 3.9+.\n"
         'To fix this error, you need to either:\n'
         '\n'
-        'A) Update to python 3.7 or later.\n'
+        'A) Update to python 3.9 or later.\n'
         '- OR -\n'
         'B) Explicitly install an older deprecated-but-compatible version '
-        'of cirq (e.g. "python -m pip install cirq==0.5.*")'
+        'of cirq (e.g. "python -m pip install cirq==1.1.*")'
     )
 
 __version__ = "1.2.0.dev"

cirq-core/cirq/protocols/json_serialization_test.py

@@ -57,8 +57,8 @@ class _ModuleDeprecation:
 
 
 # pyQuil 3.0, necessary for cirq_rigetti module requires
-# python >= 3.7
-if sys.version_info < (3, 7):  # pragma: no cover
+# python >= 3.9
+if sys.version_info < (3, 9):  # pragma: no cover
     del TESTED_MODULES['cirq_rigetti']
 
 

cirq-core/cirq/study/resolver_test.py

@@ -15,7 +15,6 @@
 """Tests for parameter resolvers."""
 
 import fractions
-import sys
 
 import numpy as np
 import pytest
@@ -243,10 +242,6 @@ def _resolved_value_(self):
     assert r.value_of(b) == 'Baz'
 
 
-# sympy 1.12 does not support Python 3.7
-@pytest.mark.xfail(
-    condition=sys.version_info < (3, 8, 0), reason='this test requires sympy 1.12', strict=True
-)
 def test_custom_value_not_implemented():
     class Bar:
         def _resolved_value_(self):

cirq-core/requirements.txt

@@ -1,8 +1,5 @@
 # Runtime requirements for the python 3 version of cirq.
 
-# functools.cached_property was introduced in python 3.8
-backports.cached_property~=1.0.1; python_version < '3.8'
-
 duet~=0.2.8
 matplotlib~=3.0
 networkx>=2.4

cirq-core/setup.py

@@ -63,7 +63,7 @@
     url='http://github.com/quantumlib/cirq',
     author='The Cirq Developers',
     author_email='cirq-dev@googlegroups.com',
-    python_requires=('>=3.7.0'),
+    python_requires=('>=3.9.0'),
     install_requires=requirements,
     extras_require={'contrib': contrib_requirements},
     license='Apache 2',

cirq-ft/cirq_ft/algos/and_gate.ipynb

@@ -223,4 +223,4 @@
  },
  "nbformat": 4,
  "nbformat_minor": 5
-}
+}

cirq-ft/cirq_ft/infra/gate_with_registers.py

@@ -13,15 +13,12 @@
 # limitations under the License.
 
 import abc
-import sys
 from typing import Dict, Iterable, List, Optional, Sequence, Tuple, Union, overload
 
 import attr
 import cirq
 import numpy as np
 
-assert sys.version_info > (3, 6), "https://docs.python.org/3/whatsnew/3.6.html#whatsnew36-pep468"
-
 
 @attr.frozen
 class Register:

cirq-ft/setup.py

@@ -59,7 +59,7 @@
     url='http://github.com/quantumlib/cirq',
     author='The Cirq Developers',
     author_email='cirq-dev@googlegroups.com',
-    python_requires='>=3.7.0',
+    python_requires='>=3.9.0',
     install_requires=requirements,
     license='Apache 2',
     description=description,

cirq-google/cirq_google/_version.py

@@ -13,20 +13,20 @@
 # limitations under the License.
 
 """Define version number here, read it from setup.py automatically,
-and warn users that the latest version of cirq uses python 3.7+"""
+and warn users that the latest version of cirq uses python 3.9+"""
 
 import sys
 
-if sys.version_info < (3, 7, 0):
+if sys.version_info < (3, 9, 0):
     # coverage: ignore
     raise SystemError(
-        "You installed the latest version of cirq but aren't on python 3.7+.\n"
+        "You installed the latest version of cirq but aren't on python 3.9+.\n"
         'To fix this error, you need to either:\n'
         '\n'
-        'A) Update to python 3.7 or later.\n'
+        'A) Update to python 3.9 or later.\n'
         '- OR -\n'
         'B) Explicitly install an older deprecated-but-compatible version '
-        'of cirq (e.g. "python -m pip install cirq==0.5.*")'
+        'of cirq (e.g. "python -m pip install cirq==1.1.*")'
     )
 
 __version__ = "1.2.0.dev"