Make ipython fully optional (google#78)

* Fall back on custom info function if IPython's oinspect is not available, thereby making IPython an optional dependency.
* Test IPython if IPython available, otherwise test with 'code' module.

Author: dbieber

.travis.yml

@@ -10,5 +10,7 @@ before_install:
 install:
   - python setup.py develop
 script:
-  - python -m pytest
+  - python -m pytest  # Run the tests without IPython.
+  - pip install ipython
+  - python -m pytest  # Now run the tests with IPython.
   - if [[ $TRAVIS_PYTHON_VERSION != 3.6 ]]; then pylint fire --ignore=test_components_py3.py,parser_fuzz_test.py; fi

fire/core.py

@@ -352,7 +352,7 @@ def _Fire(component, args, context, name=None):
 
       try:
         target = component.__name__
-        filename, lineno = _GetFileAndLine(component)
+        filename, lineno = inspectutils.GetFileAndLine(component)
 
         component, consumed_args, remaining_args, capacity = _CallCallable(
             component, remaining_args)
@@ -428,7 +428,7 @@ def _Fire(component, args, context, name=None):
         component, consumed_args, remaining_args = _GetMember(
             component, remaining_args)
 
-        filename, lineno = _GetFileAndLine(component)
+        filename, lineno = inspectutils.GetFileAndLine(component)
 
         component_trace.AddAccessedProperty(
             component, target, consumed_args, filename, lineno)
@@ -486,33 +486,6 @@ def _Fire(component, args, context, name=None):
   return component_trace
 
 
-def _GetFileAndLine(component):
-  """Returns the filename and line number of component.
-
-  Args:
-    component: A component to find the source information for, usually a class
-        or routine.
-  Returns:
-    filename: The name of the file where component is defined.
-    lineno: The line number where component is defined.
-  """
-  if inspect.isbuiltin(component):
-    return None, None
-
-  try:
-    filename = inspect.getsourcefile(component)
-  except TypeError:
-    return None, None
-
-  try:
-    unused_code, lineindex = inspect.findsource(component)
-    lineno = lineindex + 1
-  except IOError:
-    lineno = None
-
-  return filename, lineno
-
-
 def _GetMember(component, args):
   """Returns a subcomponent of component by consuming an arg from args.
 

fire/helputils_test.py

@@ -43,7 +43,8 @@ def testHelpStringObject(self):
     self.assertIn('Type:        NoDefaults', helpstring)
     self.assertIn('String form: <fire.test_components.NoDefaults object at ',
                   helpstring)
-    self.assertIn('test_components.py', helpstring)
+    # TODO: We comment this out since it only works with IPython:
+    # self.assertIn('test_components.py', helpstring)
     self.assertIn('Usage:       double\n'
                   '             triple', helpstring)
 

fire/inspectutils.py

@@ -111,6 +111,33 @@ def GetFullArgSpec(fn):
                      kwonlyargs, kwonlydefaults, annotations)
 
 
+def GetFileAndLine(component):
+  """Returns the filename and line number of component.
+
+  Args:
+    component: A component to find the source information for, usually a class
+        or routine.
+  Returns:
+    filename: The name of the file where component is defined.
+    lineno: The line number where component is defined.
+  """
+  if inspect.isbuiltin(component):
+    return None, None
+
+  try:
+    filename = inspect.getsourcefile(component)
+  except TypeError:
+    return None, None
+
+  try:
+    unused_code, lineindex = inspect.findsource(component)
+    lineno = lineindex + 1
+  except IOError:
+    lineno = None
+
+  return filename, lineno
+
+
 def Info(component):
   """Returns a dict with information about the given component.
 
@@ -130,9 +157,12 @@ def Info(component):
   Returns:
     A dict with information about the component.
   """
-  import IPython  # pylint: disable=g-import-not-at-top
-  inspector = IPython.core.oinspect.Inspector()
-  info = inspector.info(component)
+  try:
+    from IPython.core import oinspect  # pylint: disable=g-import-not-at-top
+    inspector = oinspect.Inspector()
+    info = inspector.info(component)
+  except ImportError:
+    info = _InfoBackup(component)
 
   try:
     unused_code, lineindex = inspect.findsource(component)
@@ -141,3 +171,34 @@ def Info(component):
     info['line'] = None
 
   return info
+
+
+def _InfoBackup(component):
+  """Returns a dict with information about the given component.
+
+  This function is to be called only in the case that IPython's
+  oinspect module is not available. The info dict it produces may
+  contain less information that contained in the info dict produced
+  by oinspect.
+
+  Args:
+    component: The component to analyze.
+  Returns:
+    A dict with information about the component.
+  """
+  info = {}
+
+  info['type_name'] = type(component).__name__
+  info['string_form'] = str(component)
+
+  filename, lineno = GetFileAndLine(component)
+  info['file'] = filename
+  info['line'] = lineno
+  info['docstring'] = inspect.getdoc(component)
+
+  try:
+    info['length'] = str(len(component))
+  except (TypeError, AttributeError):
+    pass
+
+  return info

fire/interact_test.py

@@ -24,22 +24,29 @@
 import mock
 
 
+try:
+  import IPython  # pylint: disable=unused-import, g-import-not-at-top
+  INTERACT_METHOD = 'IPython.start_ipython'
+except ImportError:
+  INTERACT_METHOD = 'code.InteractiveConsole'
+
+
 class InteractTest(testutils.BaseTestCase):
 
-  @mock.patch('IPython.start_ipython')
-  def testInteract(self, mock_ipython):
-    self.assertFalse(mock_ipython.called)
+  @mock.patch(INTERACT_METHOD)
+  def testInteract(self, mock_interact_method):
+    self.assertFalse(mock_interact_method.called)
     interact.Embed({})
-    self.assertTrue(mock_ipython.called)
+    self.assertTrue(mock_interact_method.called)
 
-  @mock.patch('IPython.start_ipython')
-  def testInteractVariables(self, mock_ipython):
-    self.assertFalse(mock_ipython.called)
+  @mock.patch(INTERACT_METHOD)
+  def testInteractVariables(self, mock_interact_method):
+    self.assertFalse(mock_interact_method.called)
     interact.Embed({
         'count': 10,
         'mock': mock,
     })
-    self.assertTrue(mock_ipython.called)
+    self.assertTrue(mock_interact_method.called)
 
 if __name__ == '__main__':
   testutils.main()

setup.py

@@ -30,7 +30,6 @@
 A library for automatically generating command line interfaces.""".strip()
 
 DEPENDENCIES = [
-    'ipython<6.0',
     'six',
 ]