Config: make the configparser always defined to allow to set options at any moment

mylib/config.py

@@ -70,7 +70,7 @@ class BaseOption:  # pylint: disable=too-many-instance-attributes
     def _isset_in_config_file(self):
         """ Check if option is defined in the loaded configuration file """
         return (
-            self.config.config_parser
+            self.config.config_filepath
             and self.config.config_parser.has_option(self.section.name, self.name)
         )
 
@@ -100,26 +100,23 @@ class BaseOption:  # pylint: disable=too-many-instance-attributes
         return self.default
 
     def set(self, value):
-        """ Set option value to config file """
-        assert self.config.config_parser or (self.config.options and not self.no_arg), (
-            "Can't set option value: configuration file not configured, not options (or no argument)")
+        """ Set option value to config file and options """
         if value == '':
             value = None
 
-        if self.config.config_parser:
-            if value == self.default or value is None:
-                # Remove option from config (is section exists)
-                if self.config.config_parser.has_section(self.section.name):
-                    self.config.config_parser.remove_option(
-                        self.section.name, self.name)
-            else:
-                # Store option to config
-                if not self.config.config_parser.has_section(self.section.name):
-                    self.config.config_parser.add_section(self.section.name)
+        if value == self.default or value is None:
+            # Remove option from config (is section exists)
+            if self.config.config_parser.has_section(self.section.name):
+                self.config.config_parser.remove_option(
+                    self.section.name, self.name)
+        else:
+            # Store option to config
+            if not self.config.config_parser.has_section(self.section.name):
+                self.config.config_parser.add_section(self.section.name)
 
-                self.config.config_parser.set(
-                    self.section.name, self.name, self.to_config(value)
-                )
+            self.config.config_parser.set(
+                self.section.name, self.name, self.to_config(value)
+            )
 
         if self.config.options and not self.no_arg:
             setattr(self.config.options, self.parser_dest, value)
@@ -622,6 +619,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
         self._filepath = None
         self.config_file_env_variable = config_file_env_variable
         self.default_config_dirpath = default_config_dirpath
+        self._init_config_parser()
 
     def add_section(self, name, loaded_callback=None, **kwargs):
         """
@@ -638,7 +636,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
         if loaded_callback:
             self._loaded_callbacks.append(loaded_callback)
             # If configuration is already loaded, execute callback immediatly
-            if self.config_parser or self.options:
+            if self._filepath or self.options:
                 self._loaded()
         return self.sections[name]
 
@@ -652,7 +650,6 @@ class Config:  # pylint: disable=too-many-instance-attributes
 
     def get(self, section, option):
         """ Get option value """
-        assert self.config_parser or self.options, 'Unconfigured options parser'
         assert self.defined(
             section, option), f'Unknown option {section}.{option}'
         value = self.sections[section].get(option)
@@ -666,21 +663,24 @@ class Config:  # pylint: disable=too-many-instance-attributes
         return default
 
     def __getitem__(self, key):
-        assert self.config_parser or self.options, 'Unconfigured options parser'
         assert key in self.sections, f'Unknown section {key}'
         return ConfigSectionAsDictWrapper(self.sections[key])
 
     def set(self, section, option, value):
         """ Set option value """
-        assert self.config_parser, 'Unconfigured options parser'
         assert self.defined(
             section, option), f'Unknown option {section}.{option}'
+        self._init_config_parser()
         self.sections[section].set(option, value)
 
+    def _init_config_parser(self, force=False):
+        """ Initialize ConfigParser object """
+        if not self.config_parser or force:
+            self.config_parser = ConfigParser(defaults={'hash': '#'})
+
     def load_file(self, filepath, execute_callback=True):
         """ Read configuration file """
-
-        self.config_parser = ConfigParser(defaults={'hash': '#'})
+        self._init_config_parser(force=True)
         self._filepath = filepath
 
         # Checking access of configuration file
@@ -693,7 +693,7 @@ class Config:  # pylint: disable=too-many-instance-attributes
         try:
             self.config_parser.read(filepath, encoding=self.encoding)
         except Exception:  # pylint: disable=broad-except
-            self.config_parser = None
+            self._init_config_parser(force=True)
             log.exception('Failed to read configuration file %s', filepath)
             return False
 
@@ -953,9 +953,6 @@ class Config:  # pylint: disable=too-many-instance-attributes
         section and their options value.
         :rtype: bool of dict
         """
-        # On set it mode, ensure configuration file parser is initialized
-        if set_it and not self.config_parser:
-            self.config_parser = ConfigParser()
         result = {}
         error = False
         for name, section in self.sections.items():