Support create_app without script_info or with script_info as named argument

CHANGES

@@ -42,6 +42,10 @@ Major release, unreleased
   (`#2282`_)
 - Auto-detect zero-argument app factory called ``create_app`` or ``make_app``
   from ``FLASK_APP``. (`#2297`_)
+- Factory functions are not required to take a ``script_info`` parameter to
+  work with the ``flask`` command. If they take a single parameter or a
+  parameter named ``script_info``, the ``ScriptInfo`` object will be passed.
+  (`#2319`_)
 
 .. _#1489: https://github.com/pallets/flask/pull/1489
 .. _#1898: https://github.com/pallets/flask/pull/1898
@@ -53,6 +57,7 @@ Major release, unreleased
 .. _#2259: https://github.com/pallets/flask/pull/2259
 .. _#2282: https://github.com/pallets/flask/pull/2282
 .. _#2297: https://github.com/pallets/flask/pull/2297
+.. _#2319: https://github.com/pallets/flask/pull/2319
 
 Version 0.12.2
 --------------

flask/_compat.py

@@ -25,6 +25,7 @@
     itervalues = lambda d: iter(d.values())
     iteritems = lambda d: iter(d.items())
 
+    from inspect import getfullargspec as getargspec
     from io import StringIO
 
     def reraise(tp, value, tb=None):
@@ -43,6 +44,7 @@ def reraise(tp, value, tb=None):
     itervalues = lambda d: d.itervalues()
     iteritems = lambda d: d.iteritems()
 
+    from inspect import getargspec
     from cStringIO import StringIO
 
     exec('def reraise(tp, value, tb=None):\n raise tp, value, tb')

flask/cli.py

@@ -22,13 +22,14 @@
 from ._compat import iteritems, reraise
 from .globals import current_app
 from .helpers import get_debug_flag
+from ._compat import getargspec
 
 
 class NoAppException(click.UsageError):
     """Raised if an application cannot be found or loaded."""
 
 
-def find_best_app(module):
+def find_best_app(script_info, module):
     """Given a module instance this tries to find the best possible
     application in the module or raises an exception.
     """
@@ -60,8 +61,7 @@ def find_best_app(module):
 
         if callable(app_factory):
             try:
-                app = app_factory()
-
+                app = call_factory(app_factory, script_info)
                 if isinstance(app, Flask):
                     return app
             except TypeError:
@@ -79,6 +79,20 @@ def find_best_app(module):
     )
 
 
+def call_factory(func, script_info):
+    """Checks if the given app factory function has an argument named 
+    ``script_info`` or just a single argument and calls the function passing 
+    ``script_info`` if so. Otherwise, calls the function without any arguments
+    and returns the result.
+    """
+    arguments = getargspec(func).args
+    if 'script_info' in arguments:
+        return func(script_info=script_info)
+    elif len(arguments) == 1:
+        return func(script_info)
+    return func()
+
+
 def prepare_exec_for_file(filename):
     """Given a filename this will try to calculate the python path, add it
     to the search path and return the actual module name that is expected.
@@ -108,7 +122,7 @@ def prepare_exec_for_file(filename):
     return '.'.join(module[::-1])
 
 
-def locate_app(app_id):
+def locate_app(script_info, app_id):
     """Attempts to locate the application."""
     __traceback_hide__ = True
     if ':' in app_id:
@@ -134,7 +148,7 @@ def locate_app(app_id):
 
     mod = sys.modules[module]
     if app_obj is None:
-        app = find_best_app(mod)
+        app = find_best_app(script_info, mod)
     else:
         app = getattr(mod, app_obj, None)
         if app is None:
@@ -259,15 +273,15 @@ def load_app(self):
         if self._loaded_app is not None:
             return self._loaded_app
         if self.create_app is not None:
-            rv = self.create_app(self)
+            rv = call_factory(self.create_app, self)
         else:
             if not self.app_import_path:
                 raise NoAppException(
                     'Could not locate Flask application. You did not provide '
                     'the FLASK_APP environment variable.\n\nFor more '
                     'information see '
                     'http://flask.pocoo.org/docs/latest/quickstart/')
-            rv = locate_app(self.app_import_path)
+            rv = locate_app(self, self.app_import_path)
         debug = get_debug_flag()
         if debug is not None:
             rv.debug = debug

tests/test_cli.py

@@ -39,60 +39,75 @@ def test_cli_name(test_apps):
 
 def test_find_best_app(test_apps):
     """Test if `find_best_app` behaves as expected with different combinations of input."""
+    script_info = ScriptInfo()
     class Module:
         app = Flask('appname')
-    assert find_best_app(Module) == Module.app
+    assert find_best_app(script_info, Module) == Module.app
 
     class Module:
         application = Flask('appname')
-    assert find_best_app(Module) == Module.application
+    assert find_best_app(script_info, Module) == Module.application
 
     class Module:
         myapp = Flask('appname')
-    assert find_best_app(Module) == Module.myapp
+    assert find_best_app(script_info, Module) == Module.myapp
 
     class Module:
         @staticmethod
         def create_app():
             return Flask('appname')
-    assert isinstance(find_best_app(Module), Flask)
-    assert find_best_app(Module).name == 'appname'
+    assert isinstance(find_best_app(script_info, Module), Flask)
+    assert find_best_app(script_info, Module).name == 'appname'
+
+    class Module:
+        @staticmethod
+        def create_app(foo):
+            return Flask('appname')
+    assert isinstance(find_best_app(script_info, Module), Flask)
+    assert find_best_app(script_info, Module).name == 'appname'
+
+    class Module:
+        @staticmethod
+        def create_app(foo=None, script_info=None):
+            return Flask('appname')
+    assert isinstance(find_best_app(script_info, Module), Flask)
+    assert find_best_app(script_info, Module).name == 'appname'
 
     class Module:
         @staticmethod
         def make_app():
             return Flask('appname')
-    assert isinstance(find_best_app(Module), Flask)
-    assert find_best_app(Module).name == 'appname'
+    assert isinstance(find_best_app(script_info, Module), Flask)
+    assert find_best_app(script_info, Module).name == 'appname'
 
     class Module:
         myapp = Flask('appname1')
         @staticmethod
         def create_app():
             return Flask('appname2')
-    assert find_best_app(Module) == Module.myapp
+    assert find_best_app(script_info, Module) == Module.myapp
 
     class Module:
         myapp = Flask('appname1')
         @staticmethod
-        def create_app(foo):
+        def create_app():
             return Flask('appname2')
-    assert find_best_app(Module) == Module.myapp
+    assert find_best_app(script_info, Module) == Module.myapp
 
     class Module:
         pass
-    pytest.raises(NoAppException, find_best_app, Module)
+    pytest.raises(NoAppException, find_best_app, script_info, Module)
 
     class Module:
         myapp1 = Flask('appname1')
         myapp2 = Flask('appname2')
-    pytest.raises(NoAppException, find_best_app, Module)
+    pytest.raises(NoAppException, find_best_app, script_info, Module)
 
     class Module:
         @staticmethod
-        def create_app(foo):
+        def create_app(foo, bar):
             return Flask('appname2')
-    pytest.raises(NoAppException, find_best_app, Module)
+    pytest.raises(NoAppException, find_best_app, script_info, Module)
 
 
 def test_prepare_exec_for_file(test_apps):
@@ -117,13 +132,18 @@ def test_prepare_exec_for_file(test_apps):
 
 def test_locate_app(test_apps):
     """Test of locate_app."""
-    assert locate_app("cliapp.app").name == "testapp"
-    assert locate_app("cliapp.app:testapp").name == "testapp"
-    assert locate_app("cliapp.multiapp:app1").name == "app1"
-    pytest.raises(NoAppException, locate_app, "notanpp.py")
-    pytest.raises(NoAppException, locate_app, "cliapp/app")
-    pytest.raises(RuntimeError, locate_app, "cliapp.app:notanapp")
-    pytest.raises(NoAppException, locate_app, "cliapp.importerrorapp")
+    script_info = ScriptInfo()
+    assert locate_app(script_info, "cliapp.app").name == "testapp"
+    assert locate_app(script_info, "cliapp.app:testapp").name == "testapp"
+    assert locate_app(script_info, "cliapp.multiapp:app1").name == "app1"
+    pytest.raises(NoAppException, locate_app,
+                  script_info, "notanpp.py")
+    pytest.raises(NoAppException, locate_app,
+                  script_info, "cliapp/app")
+    pytest.raises(RuntimeError, locate_app,
+                  script_info, "cliapp.app:notanapp")
+    pytest.raises(NoAppException, locate_app,
+                  script_info, "cliapp.importerrorapp")
 
 
 def test_find_default_import_path(test_apps, monkeypatch, tmpdir):