From ced719ea18a56f6c4075e08dbe05f0e77eac1866 Mon Sep 17 00:00:00 2001
From: Hendrik Makait <hendrik.makait@googlemail.com>
Date: Mon, 22 May 2017 12:30:18 -0700
Subject: [PATCH] Auto-detect create_app and make_app factory functions

---
 flask/cli.py      | 15 +++++++++++++++
 tests/test_cli.py | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/flask/cli.py b/flask/cli.py
index 3d361be8..cdb7f094 100644
--- a/flask/cli.py
+++ b/flask/cli.py
@@ -46,6 +46,21 @@ def find_best_app(module):
 
     if len(matches) == 1:
         return matches[0]
+
+    # Search for app factory callables.
+    for attr_name in 'create_app', 'make_app':
+        app_factory = getattr(module, attr_name, None)
+        if app_factory is not None and callable(app_factory):
+            try:
+                app = app_factory()
+                if app is not None and isinstance(app, Flask):
+                    return app
+            except TypeError:
+                raise NoAppException('Auto-detected "%s()" in module "%s", '
+                                     'but could not call it without '
+                                     'specifying arguments.'
+                                     % (attr_name, module.__name__))
+
     raise NoAppException('Failed to find application in module "%s".  Are '
                          'you sure it contains a Flask application?  Maybe '
                          'you wrapped it in a WSGI middleware or you are '
diff --git a/tests/test_cli.py b/tests/test_cli.py
index ab875cef..bbb6fe58 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -51,6 +51,34 @@ def test_find_best_app(test_apps):
         myapp = Flask('appname')
     assert find_best_app(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'
+
+    class Module:
+        @staticmethod
+        def make_app():
+            return Flask('appname')
+    assert isinstance(find_best_app(Module), Flask)
+    assert find_best_app(Module).name == 'appname'
+
+    class Module:
+        myapp = Flask('appname1')
+        @staticmethod
+        def create_app():
+            return Flask('appname2')
+    assert find_best_app(Module) == Module.myapp
+
+    class Module:
+        myapp = Flask('appname1')
+        @staticmethod
+        def create_app(foo):
+            return Flask('appname2')
+    assert find_best_app(Module) == Module.myapp
+
     class Module:
         pass
     pytest.raises(NoAppException, find_best_app, Module)
@@ -60,6 +88,12 @@ def test_find_best_app(test_apps):
         myapp2 = Flask('appname2')
     pytest.raises(NoAppException, find_best_app, Module)
 
+    class Module:
+        @staticmethod
+        def create_app(foo):
+            return Flask('appname2')
+    pytest.raises(NoAppException, find_best_app, Module)
+
 
 def test_prepare_exec_for_file(test_apps):
     """Expect the correct path to be set and the correct module name to be returned.