Drop support for python 3.5

This commit drops support for running with python 3.5. It marks the
minimum supported version of the package as python 3.6, removes python
3.5 package pins, removes the 3.5 CI jobs, and removes the warning on
python 3.5. Looking at the PyPI stats since the deprecation period
started the number of users on Python 3.5 has diminished significantly,
but not disappeared. There were 783 downloads with pip from pypi out of
total of 25782 total pip downloads in the last 30 days. Compared to the
roughly 10% figure when we deprecated Python 3.5.

Merging this means we can not release until after the documented EoL
date for Python 3.5 support of September 13. This shouldn't be a problem
because with Qiskit#4767 we will need to coordinate the release of all the
qiskit elements and are planning to do that after 09/13/2020.

It's worth noting that we should start planning to deprecate python 3.6
support sooner rather than later it goes EoL upstream at the end of
next year [1] and some of our other upstream dependencies (mainly numpy
et al) are going to remove support before the upstream Python EoL date
[2].

[1] https://devguide.python.org/#branchstatus
[2] https://numpy.org/neps/nep-0029-deprecation_policy.html

azure-pipelines.yml

@@ -28,7 +28,7 @@ stages:
       variables:
         python.version: '3.7'
         CIBW_BEFORE_BUILD: pip install -U Cython
-        CIBW_SKIP: cp27-* cp34-* pp*
+        CIBW_SKIP: cp27-* cp34-* cp35-* pp*
         TWINE_USERNAME: qiskit
         CIBW_TEST_COMMAND: python {project}/examples/python/stochastic_swap.py
       steps:
@@ -72,7 +72,7 @@ stages:
       variables:
         python.version: '3.7'
         CIBW_BEFORE_BUILD: pip install -U Cython
-        CIBW_SKIP: cp27-* cp34-* pp*
+        CIBW_SKIP: cp27-* cp34-* cp35-* pp*
         TWINE_USERNAME: qiskit
         CIBW_TEST_COMMAND: python {project}/examples/python/stochastic_swap.py
       steps:
@@ -95,16 +95,16 @@ stages:
       condition: startsWith(variables['Build.SourceBranch'], 'refs/tags')
       variables:
         CIBW_BEFORE_BUILD: pip install -U Cython
-        CIBW_SKIP: cp27-* cp34-* pp*
+        CIBW_SKIP: cp27-* cp34-* cp35-* pp*
         TWINE_USERNAME: qiskit
         CIBW_TEST_COMMAND: python {project}\examples\python\stochastic_swap.py
       steps:
-        - {task: UsePythonVersion@0, inputs: {versionSpec: '3.5', architecture: x86}}
-        - {task: UsePythonVersion@0, inputs: {versionSpec: '3.5', architecture: x64}}
         - {task: UsePythonVersion@0, inputs: {versionSpec: '3.6', architecture: x86}}
         - {task: UsePythonVersion@0, inputs: {versionSpec: '3.6', architecture: x64}}
         - {task: UsePythonVersion@0, inputs: {versionSpec: '3.7', architecture: x86}}
         - {task: UsePythonVersion@0, inputs: {versionSpec: '3.7', architecture: x64}}
+        - {task: UsePythonVersion@0, inputs: {versionSpec: '3.8', architecture: x86}}
+        - {task: UsePythonVersion@0, inputs: {versionSpec: '3.8', architecture: x64}}
         - script: choco install vcpython27 -f -y
           displayName: Install Visual C++ for Python 2.7
         - bash: |
@@ -349,8 +349,6 @@ stages:
       pool: {vmImage: 'vs2017-win2016'}
       strategy:
         matrix:
-          Python35:
-            python.version: '3.5'
           Python36:
             python.version: '3.6'
           Python37:
@@ -423,8 +421,6 @@ stages:
         matrix:
           Python36:
             python.version: '3.6'
-          Python35:
-            python.version: '3.5'
           Python38:
             python.version: '3.8'
       variables:
@@ -494,8 +490,6 @@ stages:
         matrix:
           Python36:
             python.version: '3.6'
-          Python35:
-            python.version: '3.5'
           Python38:
             python.version: '3.8'
       variables:

qiskit/__init__.py

@@ -16,7 +16,6 @@
 """Main Qiskit public functionality."""
 
 import pkgutil
-import sys
 import warnings
 import os
 
@@ -82,11 +81,4 @@
 from .version import _get_qiskit_versions  # noqa
 
 
-if sys.version_info[0] == 3 and sys.version_info[1] == 5:
-    warnings.warn(
-        "Using Qiskit with Python 3.5 is deprecated as of the 0.12.0 release. "
-        "Support for running Qiskit with Python 3.5 will be removed at the "
-        "Python 3.5 EoL on 09/13/2020.", DeprecationWarning)
-
-
 __qiskit_version__ = _get_qiskit_versions()

qiskit/util.py

@@ -23,12 +23,6 @@
 import psutil
 
 
-def _check_python_version():
-    """Check for Python version 3.5+."""
-    if sys.version_info < (3, 5):
-        raise Exception('Qiskit requires Python version 3.5 or greater.')
-
-
 def _filter_deprecation_warnings():
     """Apply filters to deprecation warnings.
 
@@ -55,7 +49,6 @@ def _filter_deprecation_warnings():
         pass
 
 
-_check_python_version()
 _filter_deprecation_warnings()
 
 

releasenotes/notes/drop-py3.5-86a65daa49903d46.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    The deprecated support for running qiskit-terra with Python 3.5 has been
+    removed. To use qiskit-terra >=0.16.0 you will now need at least Python 3.6.
+    If you are using Python 3.5 the last version which will work is Qiskit
+    0.15.x.

requirements-dev.txt

@@ -15,7 +15,7 @@ cython>=0.27.1
 pylatexenc>=1.4
 ddt>=1.2.0,!=1.4.0
 seaborn>=0.9.0
-reno>=3.1.0;python_version>'3.5'
+reno>=3.1.0
 Sphinx>=1.8.3,<3.1.0
 sphinx-rtd-theme>=0.4.0
 sphinx-tabs>=1.1.11

requirements.txt

@@ -1,7 +1,6 @@
 contextvars>=2.4;python_version<'3.7'
 jsonschema>=2.6
-networkx>=2.2;python_version>'3.5'
-networkx>=2.2,<2.4;python_version=='3.5'
+networkx>=2.2
 retworkx>=0.4.0
 numpy>=1.17
 ply>=3.10

setup.py

@@ -25,9 +25,7 @@
 REQUIREMENTS = [
     "contextvars>=2.4;python_version<'3.7'",
     "jsonschema>=2.6",
-    "networkx>=2.2;python_version>'3.5'",
-    # Networkx 2.4 is the final version with python 3.5 support.
-    "networkx>=2.2,<2.4;python_version=='3.5'",
+    "networkx>=2.2",
     "retworkx>=0.4.0",
     "numpy>=1.17",
     "ply>=3.10",
@@ -96,7 +94,6 @@
         "Operating System :: MacOS",
         "Operating System :: POSIX :: Linux",
         "Programming Language :: Python :: 3 :: Only",
-        "Programming Language :: Python :: 3.5",
         "Programming Language :: Python :: 3.6",
         "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
@@ -107,7 +104,7 @@
     install_requires=REQUIREMENTS,
     setup_requires=['Cython>=0.27.1'],
     include_package_data=True,
-    python_requires=">=3.5",
+    python_requires=">=3.6",
     extras_require={
         'visualization': ['matplotlib>=2.1', 'ipywidgets>=7.3.0',
                           'pydot', "pillow>=4.2.1", "pylatexenc>=1.4",

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.1
-envlist = py35, py36, py37, py38, lint
+envlist = py36, py37, py38, lint
 skipsdist = True
 
 [testenv]