Fix dotenv source extra values parsing provided in dotenv file (#221)

Author: hramezani

pydantic_settings/sources.py

@@ -684,27 +684,19 @@ def _read_env_files(self) -> Mapping[str, str | None]:
     def __call__(self) -> dict[str, Any]:
         data: dict[str, Any] = super().__call__()
 
-        data_lower_keys: list[str] = []
-        is_extra_allowed = self.config.get('extra') != 'forbid'
-        if not self.case_sensitive:
-            data_lower_keys = [x.lower() for x in data.keys()]
         # As `extra` config is allowed in dotenv settings source, We have to
         # update data with extra env variabels from dotenv file.
         for env_name, env_value in self.env_vars.items():
-            if not is_extra_allowed and not env_name.startswith(self.env_prefix):
-                raise SettingsError(
-                    "unable to load environment variables from dotenv file "
-                    f"due to the presence of variables without the specified prefix - '{self.env_prefix}'"
-                )
-            if env_name.startswith(self.env_prefix) and env_value is not None:
-                env_name_without_prefix = env_name[self.env_prefix_len :]
-                first_key, *_ = env_name_without_prefix.split(self.env_nested_delimiter)
-
-                if (data_lower_keys and first_key not in data_lower_keys) or (
-                    not data_lower_keys and first_key not in data
-                ):
-                    data[first_key] = env_value
-
+            if not env_value:
+                continue
+            env_used = False
+            for field_name, field in self.settings_cls.model_fields.items():
+                for _, field_env_name, _ in self._extract_field_info(field, field_name):
+                    if env_name.startswith(field_env_name):
+                        env_used = True
+                        break
+            if not env_used:
+                data[env_name] = env_value
         return data
 
     def __repr__(self) -> str:

tests/test_settings.py

@@ -839,12 +839,11 @@ class Settings(BaseSettings):
 
         model_config = SettingsConfigDict(env_file=p, env_prefix='prefix_')
 
-    err_msg = (
-        "unable to load environment variables from dotenv file "
-        "due to the presence of variables without the specified prefix - 'prefix_'"
-    )
-    with pytest.raises(SettingsError, match=err_msg):
+    with pytest.raises(ValidationError) as exc_info:
         Settings()
+    assert exc_info.value.errors(include_url=False) == [
+        {'type': 'extra_forbidden', 'loc': ('f',), 'msg': 'Extra inputs are not permitted', 'input': 'random value'}
+    ]
 
 
 def test_ignore_env_file_with_env_prefix_invalid(tmp_path):
@@ -2310,3 +2309,48 @@ def settings_customise_sources(
 
     s = Settings()
     assert s.model_dump() == {'json5': 5, 'json6': 6}
+
+
+def test_dotenv_with_alias_and_env_prefix(tmp_path):
+    p = tmp_path / '.env'
+    p.write_text('xxx__foo=1\nxxx__bar=2')
+
+    class Settings(BaseSettings):
+        model_config = SettingsConfigDict(env_file=p, env_prefix='xxx__')
+
+        foo: str = ''
+        bar_alias: str = Field('', validation_alias='xxx__bar')
+
+    s = Settings()
+    assert s.model_dump() == {'foo': '1', 'bar_alias': '2'}
+
+    class Settings1(BaseSettings):
+        model_config = SettingsConfigDict(env_file=p, env_prefix='xxx__')
+
+        foo: str = ''
+        bar_alias: str = Field('', alias='bar')
+
+    with pytest.raises(ValidationError) as exc_info:
+        Settings1()
+    assert exc_info.value.errors(include_url=False) == [
+        {'type': 'extra_forbidden', 'loc': ('xxx__bar',), 'msg': 'Extra inputs are not permitted', 'input': '2'}
+    ]
+
+
+def test_dotenv_with_alias_and_env_prefix_nested(tmp_path):
+    p = tmp_path / '.env'
+    p.write_text('xxx__bar=0\nxxx__nested__a=1\nxxx__nested__b=2')
+
+    class NestedSettings(BaseModel):
+        a: str = 'a'
+        b: str = 'b'
+
+    class Settings(BaseSettings):
+        model_config = SettingsConfigDict(env_prefix='xxx__', env_nested_delimiter='__', env_file=p)
+
+        foo: str = ''
+        bar_alias: str = Field('', alias='xxx__bar')
+        nested_alias: NestedSettings = Field(default_factory=NestedSettings, alias='xxx__nested')
+
+    s = Settings()
+    assert s.model_dump() == {'foo': '', 'bar_alias': '0', 'nested_alias': {'a': '1', 'b': '2'}}