Resolves Issue #136

ChangeLog

@@ -44,7 +44,10 @@ Incompatible Changes:
           live in the same file (i.e. hooks won't be registered just because
           you imported an extension to sub-class a handler, etc).
     * cement.utils.test_helper moved to cement.utils.test.
-
+    * By default, command line arguments no longer override config settings.
+      This is now configurable by the CementApp.Meta.arguments_override_config
+      boolean.
+      
 
 1.9.12 - Thu Jul 05, 2012
 ------------------------------------------------------------------------------

cement/core/foundation.py

@@ -75,6 +75,13 @@ class CementApp(meta.MetaMixin):
             and options.
             
             Default: sys.argv[1:]
+          
+        arguments_override_config
+            A boolean to toggle whether command line arguments should 
+            override configuration values if the argument name matches the
+            config key.  I.e. --foo=bar would override config['myapp']['foo'].
+            
+            Default: False
             
         config_section
             The base configuration section for the application.
@@ -310,6 +317,7 @@ class CementApp(meta.MetaMixin):
         plugin_bootstrap = None
         plugin_dir = None
         argv = list(sys.argv[1:])
+        arguments_override_config = False
         config_section = None
         config_defaults = None
         catch_signals = [signal.SIGTERM, signal.SIGINT]
@@ -585,19 +593,20 @@ class CementApp(meta.MetaMixin):
     def _parse_args(self):
         self.args.parse(self.argv)
         
-        for member in dir(self.args.parsed_args):
-            if member and member.startswith('_'):
-                continue
+        if self._meta.arguments_override_config is True:
+            for member in dir(self.args.parsed_args):
+                if member and member.startswith('_'):
+                    continue
             
-            # don't override config values for options that weren't passed
-            # or in otherwords are None
-            elif getattr(self.args.parsed_args, member) is None:
-                continue
+                # don't override config values for options that weren't passed
+                # or in otherwords are None
+                elif getattr(self.args.parsed_args, member) is None:
+                    continue
                 
-            for section in self.config.get_sections():
-                if member in self.config.keys(section):
-                    self.config.set(section, member, 
-                                    getattr(self.args.parsed_args, member))
+                for section in self.config.get_sections():
+                    if member in self.config.keys(section):
+                        self.config.set(section, member, 
+                                        getattr(self.args.parsed_args, member))
             
     def _setup_signals(self):
         if not self._meta.catch_signals:

doc/source/dev/configuration.rst

@@ -32,7 +32,8 @@ is the order in which configurations are discovered:
     * Extended by any handler Meta.config_defaults (not overridden)
     * Overridden by a config_defaults dict passed to foundation.CementApp()
     * Overridden by the configuration files
-    * Overridden by command line options that match the same key name
+    * Overridden by command line options that match the same key name (only
+      if CementApp.Meta.arguments_override_config=True)
 
 
 Application Default Settings
@@ -213,8 +214,9 @@ If no config_files meta data is provided, Cement will set the defaults to:
 Overriding Configurations with Command Line Options
 ---------------------------------------------------
 
-Config settings are automatically overridden if a passed command line option
-matches the name.  Note that this happens in *all* sections:
+Config settings can be automatically overridden by a passed command line 
+option if the argument name matches a configuration key.  Note that this will
+happen in *all* config sections:
 
 .. code-block:: python
 
@@ -223,7 +225,10 @@ matches the name.  Note that this happens in *all* sections:
     defaults = backend.defaults('base')
     defaults['base']['foo'] = 'bar'
     
-    app = foundation.CementApp('myapp', config_defaults=defaults)
+    app = foundation.CementApp('myapp', 
+        config_defaults=defaults,
+        arguments_override_config=True,
+        )
     try:
         # First setup the application
         app.setup()

tests/core/config_tests.py

@@ -27,11 +27,42 @@ class ConfigTestCase(test.CementTestCase):
         defaults = dict()
         defaults['test'] = dict()
         defaults['test']['debug'] = False
-        self.app = self.make_app(config_defaults=defaults, argv=['--debug'])
+        defaults['test']['foo'] = 'bar'
+        
+        # first test that it doesn't override the config with the default
+        # setting of arguments_override_config=False
+        self.app = self.make_app(
+            config_defaults=defaults, 
+            argv=['--foo=not_bar'],
+            arguments_override_config=False
+            )
         self.app.setup()
+        self.app.args.add_argument('--foo', action='store')
         self.app.run()
-        self.eq(self.app.config.get('test', 'debug'), True)
-
+        self.eq(self.app.config.get('test', 'foo'), 'bar')
+        
+        # then make sure that it does
+        self.app = self.make_app(
+            config_defaults=defaults, 
+            argv=['--foo=not_bar'],
+            arguments_override_config=True
+            )
+        self.app.setup()
+        self.app.args.add_argument('--foo', action='store')
+        self.app.run()
+        self.eq(self.app.config.get('test', 'foo'), 'not_bar')
+                
+        # one last test just for code coverage
+        self.app = self.make_app(
+            config_defaults=defaults, 
+            argv=['--debug'],
+            arguments_override_config=True
+            )
+        self.app.setup()
+        self.app.args.add_argument('--foo', action='store')
+        self.app.run()
+        self.eq(self.app.config.get('test', 'foo'), 'bar')
+        
     def test_parse_file_bad_path(self):
         self.app._meta.config_files = ['./some_bogus_path']
         self.app.setup()