Ignore env_prefix if validation_alias is set (#25)

Author: hramezani

pydantic_settings/sources.py

@@ -129,9 +129,7 @@ def _extract_field_info(self, field: FieldInfo, field_name: str) -> List[Tuple[s
                             (alias[0], self._apply_case_sensitive(alias[0]), True if len(alias) > 1 else False)
                         )
             else:  # string validation alias
-                field_info.append(
-                    (v_alias, self._apply_case_sensitive(self.config.get('env_prefix', '') + v_alias), False)
-                )
+                field_info.append((v_alias, self._apply_case_sensitive(v_alias), False))
         else:
             field_info.append(
                 (field_name, self._apply_case_sensitive(self.config.get('env_prefix', '') + field_name), False)

tests/test_settings.py

@@ -418,7 +418,7 @@ def test_env_inheritance_config(env):
     env.set('foobar_parent_from_config', 'foobar_parent_from_config')
     env.set('foobar_child_from_config', 'foobar_child_from_config')
 
-    env.set('prefix_foobar_child_from_field', 'prefix_foobar_child_from_field')
+    env.set('foobar_child_from_field', 'foobar_child_from_field')
 
     # a. Child class config overrides prefix
     class Parent(BaseSettings):
@@ -429,7 +429,7 @@ class Parent(BaseSettings):
     class Child(Parent):
         model_config = ConfigDict(env_prefix='prefix_')
 
-    assert Child().foobar == 'prefix_foobar_parent_from_field'
+    assert Child().foobar == 'foobar_parent_from_field'
 
     # b. Child class overrides field
     class Parent(BaseSettings):
@@ -451,7 +451,7 @@ class Child(Parent):
 
         model_config = ConfigDict(env_prefix='prefix_')
 
-    assert Child().foobar == 'prefix_foobar_child_from_field'
+    assert Child().foobar == 'foobar_child_from_field'
 
 
 def test_invalid_validation_alias(env):
@@ -498,6 +498,21 @@ class Settings(BaseSettings):
     assert Settings().foobar == 'val3'
 
 
+def test_validation_alias_with_env_prefix(env):
+    class Settings(BaseSettings):
+        foobar: str = Field(validation_alias='foo')
+
+        model_config = ConfigDict(env_prefix='p_')
+
+    env.set('p_foo', 'bar')
+    with pytest.raises(ValidationError) as exc_info:
+        Settings()
+    assert exc_info.value.errors() == [{'type': 'missing', 'loc': ('foo',), 'msg': 'Field required', 'input': {}}]
+
+    env.set('foo', 'bar')
+    assert Settings().foobar == 'bar'
+
+
 def test_case_sensitive(monkeypatch):
     class Settings(BaseSettings):
         foo: str