Add env variable and user config option to suppress packaging warnings

azure-pipelines.yml

@@ -129,6 +129,8 @@ stages:
         matrix:
           Python37:
             python.version: '3.7'
+      variables:
+        QISKIT_SUPPRESS_PACKAGING_WARNINGS: Y
       steps:
         - task: UsePythonVersion@0
           inputs:
@@ -235,6 +237,8 @@ stages:
         matrix:
           Python37:
             python.version: '3.7'
+      variables:
+        QISKIT_SUPPRESS_PACKAGING_WARNINGS: Y
       steps:
         - task: UsePythonVersion@0
           inputs:
@@ -295,6 +299,8 @@ stages:
             python.version: '3.7'
           Python38:
             python.version: '3.8'
+      variables:
+        QISKIT_SUPPRESS_PACKAGING_WARNINGS: Y
       steps:
         - task: UsePythonVersion@0
           inputs:
@@ -350,6 +356,8 @@ stages:
             python.version: '3.5'
           Python38:
             python.version: '3.8'
+      variables:
+        QISKIT_SUPPRESS_PACKAGING_WARNINGS: Y
       steps:
         - task: UsePythonVersion@0
           inputs:
@@ -406,6 +414,8 @@ stages:
             python.version: '3.5'
           Python38:
             python.version: '3.8'
+      variables:
+        QISKIT_SUPPRESS_PACKAGING_WARNINGS: Y
       steps:
         - task: UsePythonVersion@0
           inputs:

qiskit/__init__.py

@@ -12,14 +12,15 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-# pylint: disable=wrong-import-order
+# pylint: disable=wrong-import-order,invalid-name,wrong-import-position
 
 
 """Main Qiskit public functionality."""
 
 import pkgutil
 import sys
 import warnings
+import os
 
 # First, check for required Python and API version
 from . import util
@@ -32,6 +33,9 @@
 from qiskit.circuit import QuantumRegister
 from qiskit.circuit import QuantumCircuit
 
+# user config
+from qiskit import user_config as _user_config
+
 # The qiskit.extensions.x imports needs to be placed here due to the
 # mechanism for adding gates dynamically.
 import qiskit.extensions
@@ -46,29 +50,37 @@
 # Please note these are global instances, not modules.
 from qiskit.providers.basicaer import BasicAer
 
+_config = _user_config.get_config()
+
 # Try to import the Aer provider if installed.
 try:
     from qiskit.providers.aer import Aer
 except ImportError:
-    warnings.warn('Could not import the Aer provider from the qiskit-aer '
-                  'package. Install qiskit-aer or check your installation.',
-                  RuntimeWarning)
+    suppress_warnings = os.environ.get('QISKIT_SUPPRESS_PACKAGING_WARNINGS', '')
+    if suppress_warnings.upper() != 'Y':
+        if not _config.get('suppress_packaging_warnings') or suppress_warnings.upper() == 'N':
+            warnings.warn('Could not import the Aer provider from the qiskit-aer '
+                          'package. Install qiskit-aer or check your installation.',
+                          RuntimeWarning)
 # Try to import the IBMQ provider if installed.
 try:
     from qiskit.providers.ibmq import IBMQ
 except ImportError:
-    warnings.warn('Could not import the IBMQ provider from the '
-                  'qiskit-ibmq-provider package. Install qiskit-ibmq-provider '
-                  'or check your installation.',
-                  RuntimeWarning)
+    suppress_warnings = os.environ.get('QISKIT_SUPPRESS_PACKAGING_WARNINGS', '')
+    if suppress_warnings.upper() != 'Y':
+        if not _config.get('suppress_packaging_warnings') or suppress_warnings.upper() == 'N':
+            warnings.warn('Could not import the IBMQ provider from the '
+                          'qiskit-ibmq-provider package. Install '
+                          'qiskit-ibmq-provider or check your installation.',
+                          RuntimeWarning)
 
 # Moved to after IBMQ and Aer imports due to import issues
 # with other modules that check for IBMQ (tools)
-from qiskit.execute import execute
-from qiskit.compiler import transpile, assemble, schedule
+from qiskit.execute import execute  # noqa
+from qiskit.compiler import transpile, assemble, schedule  # noqa
 
-from .version import __version__
-from .version import _get_qiskit_versions
+from .version import __version__  # noqa
+from .version import _get_qiskit_versions  # noqa
 
 
 if sys.version_info[0] == 3 and sys.version_info[1] == 5:

qiskit/user_config.py

@@ -88,6 +88,11 @@ def read_config_file(self):
                         "0, 1, 2, or 3.")
                 self.settings['transpile_optimization_level'] = (
                     transpile_optimization_level)
+            # Parse package warnings
+            package_warnings = self.config_parser.getboolean(
+                'default', 'suppress_packaging_warnings', fallback=False)
+            if package_warnings:
+                self.settings['suppress_packaging_warnings'] = package_warnings
 
 
 def get_config():

releasenotes/notes/suppress-packaging-warnings-396b38feb6b3d52f.yaml

@@ -0,0 +1,25 @@
+---
+features:
+  - |
+    A new environment variable ``QISKIT_SUPPRESS_PACKAGING_WARNINGS`` can be
+    set to ``Y`` or ``y`` which will suppress the warnings about
+    ``qiskit-aer`` and ``qiskit-ibmq-provider`` not being installed at import
+    time. This is useful for users who are only running qiskit-terra (or just
+    not qiskit-aer and/or qiskit-ibmq-provider) and the warnings are not an
+    indication of a potential packaging problem. You can set the environment
+    variable to ``N`` or ``n`` to ensure that warnings are always enabled
+    even if the user config file is set to disable them.
+  - |
+    A new user config file option, ``suppress_packaging_warnings`` has been
+    added. When set to ``true`` in your user config file like::
+
+        [default]
+        suppress_packaging_warnings = true
+
+    it will suppress the warnings about  ``qiskit-aer`` and
+    ``qiskit-ibmq-provider`` not being installed at import time. This is useful
+    for users who are only running qiskit-terra (or just not qiskit-aer and/or
+    qiskit-ibmq-provider) and the warnings are not an indication of a potential
+    packaging problem. If the user config file is set to disable the warnings
+    this can be overriden by setting the ``QISKIT_SUPPRESS_PACKAGING_WARNINGS``
+    to ``N`` or ``n``

test/python/test_user_config.py

@@ -32,6 +32,18 @@ def test_empty_file_read(self):
         config.read_config_file()
         self.assertEqual({}, config.settings)
 
+    def test_invalid_suppress_packaging_warnings(self):
+        test_config = """
+        [default]
+        suppress_packaging_warnings = 76
+        """
+        self.addCleanup(os.remove, self.file_path)
+        with open(self.file_path, 'w') as file:
+            file.write(test_config)
+            file.flush()
+            config = user_config.UserConfig(self.file_path)
+            self.assertRaises(ValueError, config.read_config_file)
+
     def test_invalid_optimization_level(self):
         test_config = """
         [default]
@@ -88,12 +100,41 @@ def test_optimization_level_valid(self):
             self.assertEqual({'transpile_optimization_level': 1},
                              config.settings)
 
+    def test_valid_suppress_packaging_warnings_false(self):
+        test_config = """
+        [default]
+        suppress_packaging_warnings = false
+        """
+        self.addCleanup(os.remove, self.file_path)
+        with open(self.file_path, 'w') as file:
+            file.write(test_config)
+            file.flush()
+            config = user_config.UserConfig(self.file_path)
+            config.read_config_file()
+            self.assertEqual({},
+                             config.settings)
+
+    def test_valid_suppress_packaging_warnings_true(self):
+        test_config = """
+        [default]
+        suppress_packaging_warnings = true
+        """
+        self.addCleanup(os.remove, self.file_path)
+        with open(self.file_path, 'w') as file:
+            file.write(test_config)
+            file.flush()
+            config = user_config.UserConfig(self.file_path)
+            config.read_config_file()
+            self.assertEqual({'suppress_packaging_warnings': True},
+                             config.settings)
+
     def test_all_options_valid(self):
         test_config = """
         [default]
         circuit_drawer = latex
         circuit_mpl_style = default
         transpile_optimization_level = 3
+        suppress_packaging_warnings = true
         """
         self.addCleanup(os.remove, self.file_path)
         with open(self.file_path, 'w') as file:
@@ -103,4 +144,6 @@ def test_all_options_valid(self):
             config.read_config_file()
             self.assertEqual({'circuit_drawer': 'latex',
                               'circuit_mpl_style': 'default',
-                              'transpile_optimization_level': 3}, config.settings)
+                              'transpile_optimization_level': 3,
+                              'suppress_packaging_warnings': True},
+                             config.settings)

tox.ini

@@ -11,6 +11,7 @@ setenv =
   LANGUAGE=en_US
   LC_ALL=en_US.utf-8
   ARGS="-V"
+  QISKIT_SUPRESS_PACKAGING_WARNINGS=Y
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/requirements-dev.txt
 commands =