set TEMPLATE_AUTO_RELOAD default value to None

CHANGES

@@ -23,9 +23,9 @@ Version 1.0
 - Added :meth:`flask.Config.from_json`.
 - Added :attr:`flask.Flask.config_class`.
 - Added :meth:`flask.config.Config.get_namespace`.
-- Added ``TEMPLATES_AUTO_RELOAD`` config key. If disabled the
+- Added ``TEMPLATES_AUTO_RELOAD`` config key. Now by default templates will be
-  templates will be reloaded only if the application is running in
+  reloaded every time a template is requested only if the application is
-  debug mode. For higher performance it’s possible to disable that.
+  running in debug mode.
 - Added a workaround for a limitation in Python 3.3's namespace loader.
 - Added support for explicit root paths when using Python 3.3's namespace
   packages.

docs/config.rst

@@ -182,12 +182,12 @@ The following configuration values are used internally by Flask:
                                   if they are not requested by an
                                   XMLHttpRequest object (controlled by
                                   the ``X-Requested-With`` header)
-``TEMPLATES_AUTO_RELOAD``         Flask checks if template was modified each
+``TEMPLATES_AUTO_RELOAD``         If this is set to `True` every time a template
-                                  time it is requested and reloads it if
+                                  is requested Flask checks if the template was
-                                  necessary. But disk I/O is costly and it may
+                                  modified and if yes, it will reload the
-                                  be viable to disable this feature by setting
+                                  template. By default the value is ``None``
-                                  this key to ``False``. This option does not
+                                  which means that Flask checks template
-                                  affect debug mode.
+                                  sources only in debug mode.
 ``EXPLAIN_TEMPLATE_LOADING``      If this is enabled then every attempt to
                                   load a template will write an info
                                   message to the logger explaining the

flask/app.py

@@ -297,7 +297,7 @@ class Flask(_PackageBoundObject):
         'JSON_AS_ASCII':                        True,
         'JSON_SORT_KEYS':                       True,
         'JSONIFY_PRETTYPRINT_REGULAR':          True,
-        'TEMPLATES_AUTO_RELOAD':                True,
+        'TEMPLATES_AUTO_RELOAD':                None,
     })
 
     #: The rule object to use for URL rules created.  This is used by
@@ -673,8 +673,10 @@ class Flask(_PackageBoundObject):
         if 'autoescape' not in options:
             options['autoescape'] = self.select_jinja_autoescape
         if 'auto_reload' not in options:
-            options['auto_reload'] = self.debug \
+            if self.config['TEMPLATES_AUTO_RELOAD'] is not None:
-                or self.config['TEMPLATES_AUTO_RELOAD']
+                options['auto_reload'] = self.config['TEMPLATES_AUTO_RELOAD']
+            else:
+                options['auto_reload'] = self.debug
         rv = Environment(self, **options)
         rv.globals.update(
             url_for=url_for,

tests/test_templating.py

@@ -296,12 +296,36 @@ def test_iterable_loader():
     assert rv.data == b'<h1>Jameson</h1>'
 
 def test_templates_auto_reload():
+    # debug is False, config option is None
     app = flask.Flask(__name__)
-    assert app.config['TEMPLATES_AUTO_RELOAD']
+    assert app.debug is False
-    assert app.jinja_env.auto_reload
+    assert app.config['TEMPLATES_AUTO_RELOAD'] is None
+    assert app.jinja_env.auto_reload is False
+    # debug is False, config option is False
     app = flask.Flask(__name__)
     app.config['TEMPLATES_AUTO_RELOAD'] = False
-    assert not app.jinja_env.auto_reload
+    assert app.debug is False
+    assert app.jinja_env.auto_reload is False
+    # debug is False, config option is True
+    app = flask.Flask(__name__)
+    app.config['TEMPLATES_AUTO_RELOAD'] = True
+    assert app.debug is False
+    assert app.jinja_env.auto_reload is True
+    # debug is True, config option is None
+    app = flask.Flask(__name__)
+    app.config['DEBUG'] = True
+    assert app.config['TEMPLATES_AUTO_RELOAD'] is None
+    assert app.jinja_env.auto_reload is True
+    # debug is True, config option is False
+    app = flask.Flask(__name__)
+    app.config['DEBUG'] = True
+    app.config['TEMPLATES_AUTO_RELOAD'] = False
+    assert app.jinja_env.auto_reload is False
+    # debug is True, config option is True
+    app = flask.Flask(__name__)
+    app.config['DEBUG'] = True
+    app.config['TEMPLATES_AUTO_RELOAD'] = True
+    assert app.jinja_env.auto_reload is True
 
 def test_template_loader_debugging(test_apps):
     from blueprintapp import app