fix: fix incorrect matching env var strings with dollar sign

Author: diogosilva30

pyconfigparser.py

@@ -97,7 +97,7 @@ def _extract_env_variable_key(variable):
  return variable
 
 
-_VARIABLE_PATTERN = r'\$([a-zA-Z][\w]+|\{[a-zA-Z][\w]+\})$'
+_VARIABLE_PATTERN = r'^\$([a-zA-Z][\w]+|\{[a-zA-Z][\w]+\})$'
 _DEFAULT_CONFIG_FILES = ('config.json', 'config.yaml', 'config.yml')
 _ENTITY_NAME_PATTERN = r'^[a-zA-Z][\w]+$'
 _SUPPORTED_EXTENSIONS = {

test_configparser.py

@@ -1,4 +1,4 @@
-from pyconfigparser import ConfigParser, ConfigError, ConfigFileNotFoundError
+from pyconfigparser import ConfigParser, ConfigError, ConfigFileNotFoundError,_is_variable
 from config.schemas import SIMPLE_SCHEMA_CONFIG, UNSUPPORTED_OBJECT_KEYS_SCHEMA
 import unittest
 import os
@@ -92,6 +92,33 @@ def assign_a_bad_type_ignore_unsetted_env_vars():
  self.assertIs(configparser.ignore_unset_env_vars, True)
  self.assertIsInstance(configparser.ignore_unset_env_vars, bool)
 
+ def test_variable_pattern_matching(self) -> None:
+ """Test the regex pattern for environment variable matching."""
+
+ valid_env_vars = [
+ "$FOO",
+ "${FOO}",
+ "$My_Var123"
+ ]
+
+ invalid_env_vars = [
+ "FOO", # no $
+ "$", # missing name
+ "${}", # empty braces
+ "$1VAR", # starts with number
+ "${1VAR}", # starts with number in braces
+ "foo$VAR", # not at start
+ "<L/f\\U<Uj2{.S95@^$Rx" # random password
+ ]
+
+ for var in valid_env_vars:
+ with self.subTest(var=var):
+ self.assertTrue(_is_variable(var), f"{var} should match")
+
+ for var in invalid_env_vars:
+ with self.subTest(var=var):
+ self.assertFalse(_is_variable(var), f"{var} should not match")
+
 
 if __name__ == '__main__':
  unittest.main()