Remove namespace packaging and hardcode elements

qiskit/__init__.py

@@ -12,42 +12,66 @@
 
 # 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
 
+# Extend namespace for backwards compat
+from qiskit import namespace
+new_meta_path = []
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aer', 'qiskit.providers.aer'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_ignis', 'qiskit.ignis'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqua', 'qiskit.aqua'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqua.ai', 'qiskit.ai'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqua.chemistry', 'qiskit.chemistry'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqua.finance', 'qiskit.finance'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqua.ml', 'qiskit.ml'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqua.optimizations', 'qiskit.optimizations'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_ibmq_provider', 'qiskit.providers.ibmq'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_aqt_provider', 'qiskit.providers.aqt'))
+new_meta_path.append(namespace.QiskitElementImport(
+    'qiskit_honeywell_provider', 'qiskit.providers.honeywell'))
+# Add Qiskit importers to meta_path before PathFinder in the default
+# sys.meta_path to avoid the miss penalty on trying to import a module
+# which does not exist
+old_meta_path = sys.meta_path
+sys.meta_path = old_meta_path[:-1] + new_meta_path + [old_meta_path[-1]]
+
 # qiskit errors operator
-from qiskit.exceptions import QiskitError
+from qiskit.exceptions import QiskitError  # noqa
 
 # The main qiskit operators
-from qiskit.circuit import ClassicalRegister
-from qiskit.circuit import QuantumRegister
-from qiskit.circuit import AncillaRegister
-from qiskit.circuit import QuantumCircuit
+from qiskit.circuit import ClassicalRegister  # noqa
+from qiskit.circuit import QuantumRegister  # noqa
+from qiskit.circuit import AncillaRegister  # noqa
+from qiskit.circuit import QuantumCircuit  # noqa
 
 # user config
-from qiskit import user_config as _user_config
+from qiskit import user_config as _user_config  # noqa
 
 # The qiskit.extensions.x imports needs to be placed here due to the
 # mechanism for adding gates dynamically.
-import qiskit.extensions
-import qiskit.circuit.measure
-import qiskit.circuit.reset
-
-# Allow extending this namespace. Please note that currently this line needs
-# to be placed *before* the wrapper imports or any non-import code AND *before*
-# importing the package you want to allow extensions for (in this case `backends`).
-__path__ = pkgutil.extend_path(__path__, __name__)
+import qiskit.extensions  # noqa
+import qiskit.circuit.measure  # noqa
+import qiskit.circuit.reset  # noqa
 
 # Please note these are global instances, not modules.
-from qiskit.providers.basicaer import BasicAer
+from qiskit.providers.basicaer import BasicAer  # noqa
 
 _config = _user_config.get_config()
 
@@ -61,6 +85,7 @@
             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
@@ -73,8 +98,6 @@
                           '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  # noqa
 from qiskit.compiler import transpile, assemble, schedule  # noqa
 

qiskit/namespace.py

@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+
+# This code is part of Qiskit.
+#
+# (C) Copyright IBM 2020.
+#
+# This code is licensed under the Apache License, Version 2.0. You may
+# obtain a copy of this license in the LICENSE.txt file in the root directory
+# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
+#
+# Any modifications or derivative works of this code must retain this
+# copyright notice, and modified files need to carry a notice indicating
+# that they have been altered from the originals.
+
+# pylint: disable=unused-argument
+
+"""Module for utilities to manually construct qiskit namespace"""
+
+import sys
+from importlib.abc import MetaPathFinder, Loader
+import importlib
+
+
+class QiskitLoader(Loader):
+    """Load qiskit element as a namespace package."""
+    def __init__(self, new_package, old_namespace):
+        super().__init__()
+        self.new_package = new_package
+        self.old_namespace = old_namespace
+
+    def module_repr(self, module):
+        return repr(module)
+
+    def load_module(self, fullname):
+        old_name = fullname
+        names = fullname.split(".")
+        new_namespace_names = self.new_package.split('.')
+        old_namespace_names = self.old_namespace.split('.')
+        fullname = ".".join(
+            new_namespace_names + names[len(old_namespace_names):])
+        module = importlib.import_module(fullname)
+        sys.modules[old_name] = module
+        return module
+
+
+class QiskitElementImport(MetaPathFinder):
+    """Meta importer to enable unified qiskit namespace."""
+    def __init__(self, new_package, old_namespace):
+        super().__init__()
+        self.new_package = new_package
+        self.old_namespace = old_namespace
+
+    def find_spec(self, fullname, path=None, target=None):
+        """Return the ModuleSpec for Qiskit element."""
+        if fullname.startswith(self.old_namespace):
+            return importlib.util.spec_from_loader(
+                fullname,
+                QiskitLoader(self.new_package, self.old_namespace),
+                origin='qiskit')
+        return None

qiskit/providers/__init__.py

@@ -47,15 +47,9 @@
    JobTimeoutError
 """
 
-import pkgutil
-
 from .basebackend import BaseBackend
 from .baseprovider import BaseProvider
 from .basejob import BaseJob
 from .exceptions import (JobError, JobTimeoutError, QiskitBackendNotFoundError,
                          BackendPropertyError, BackendConfigurationError)
 from .jobstatus import JobStatus
-
-
-# Allow extending this namespace.
-__path__ = pkgutil.extend_path(__path__, __name__)

qiskit/tools/jupyter/job_watcher.py

@@ -176,5 +176,6 @@ def qiskit_disable_job_watcher(self, line='', cell=None):
         _JOB_WATCHER.stop_viewer()
 
 
-# The Jupyter job watcher instance
-_JOB_WATCHER = JobWatcher()
+if HAS_IBMQ:
+    # The Jupyter job watcher instance
+    _JOB_WATCHER = JobWatcher()

qiskit/version.py

@@ -10,7 +10,7 @@
 # copyright notice, and modified files need to carry a notice indicating
 # that they have been altered from the originals.
 
-# pylint: disable=no-name-in-module,broad-except,cyclic-import
+# pylint: disable=no-name-in-module,broad-except,cyclic-import,import-error
 
 """Contains the terra version."""
 
@@ -85,22 +85,22 @@ def _get_qiskit_versions():
     out_dict = {}
     out_dict['qiskit-terra'] = __version__
     try:
-        from qiskit.providers import aer
+        import qiskit_aer as aer
         out_dict['qiskit-aer'] = aer.__version__
     except Exception:
         out_dict['qiskit-aer'] = None
     try:
-        from qiskit import ignis
+        import qiskit_ignis as ignis
         out_dict['qiskit-ignis'] = ignis.__version__
     except Exception:
         out_dict['qiskit-ignis'] = None
     try:
-        from qiskit.providers import ibmq
+        import qiskit_ibmq_provider as ibmq
         out_dict['qiskit-ibmq-provider'] = ibmq.__version__
     except Exception:
         out_dict['qiskit-ibmq-provider'] = None
     try:
-        from qiskit import aqua
+        import qiskit_aqua as aqua
         out_dict['qiskit-aqua'] = aqua.__version__
     except Exception:
         out_dict['qiskit-aqua'] = None

tox.ini

@@ -11,7 +11,7 @@ setenv =
   LANGUAGE=en_US
   LC_ALL=en_US.utf-8
   ARGS="-V"
-  QISKIT_SUPRESS_PACKAGING_WARNINGS=Y
+  QISKIT_SUPPRESS_PACKAGING_WARNINGS=Y
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/requirements-dev.txt
 commands =
@@ -40,6 +40,7 @@ basepython = python3
 setenv =
   {[testenv]setenv}
   QISKIT_DOCS=TRUE
+  QISKIT_SUPPRESS_PACKAGING_WARNINGS=Y
 deps =
   -r{toxinidir}/requirements-dev.txt
   qiskit-aer