From 112b07ef9036d826c234ed92b9b19c8370ac0b52 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 14:05:43 -0500
Subject: [PATCH 01/15] optionally gather line_errors from each source

---
 pydantic_settings/main.py | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index 9a139d1e..1b1a22f1 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -2,6 +2,7 @@
 
 import asyncio
 import inspect
+import json
 import threading
 from argparse import Namespace
 from types import SimpleNamespace
@@ -13,6 +14,7 @@
 from pydantic._internal._utils import deep_update, is_model_class
 from pydantic.dataclasses import is_pydantic_dataclass
 from pydantic.main import BaseModel
+from pydantic_core import ValidationError, InitErrorDetails
 
 from .sources import (
     ENV_FILE_SENTINEL,
@@ -32,7 +34,6 @@
 
 T = TypeVar('T')
 
-
 class SettingsConfigDict(ConfigDict, total=False):
     case_sensitive: bool
     nested_model_default_partial_update: bool | None
@@ -58,6 +59,7 @@ class SettingsConfigDict(ConfigDict, total=False):
     cli_ignore_unknown_args: bool | None
     cli_kebab_case: bool | None
     secrets_dir: PathType | None
+    validate_each_source: bool | None
     json_file: PathType | None
     json_file_encoding: str | None
     yaml_file: PathType | None
@@ -257,6 +259,7 @@ def _settings_build_values(
         _cli_ignore_unknown_args: bool | None = None,
         _cli_kebab_case: bool | None = None,
         _secrets_dir: PathType | None = None,
+        _validate_each_source: bool | None = None
     ) -> dict[str, Any]:
         # Determine settings config values
         case_sensitive = _case_sensitive if _case_sensitive is not None else self.model_config.get('case_sensitive')
@@ -332,6 +335,8 @@ def _settings_build_values(
 
         secrets_dir = _secrets_dir if _secrets_dir is not None else self.model_config.get('secrets_dir')
 
+        validate_each_source = _validate_each_source if _validate_each_source is not None else self.model_config.get("validate_each_source")
+
         # Configure built-in sources
         default_settings = DefaultSettingsSource(
             self.__class__, nested_model_default_partial_update=nested_model_default_partial_update
@@ -400,6 +405,7 @@ def _settings_build_values(
         if sources:
             state: dict[str, Any] = {}
             states: dict[str, dict[str, Any]] = {}
+            all_line_errors: list[dict[str, Any]] = []
             for source in sources:
                 if isinstance(source, PydanticBaseSettingsSource):
                     source._set_current_state(state)
@@ -410,6 +416,26 @@ def _settings_build_values(
 
                 states[source_name] = source_state
                 state = deep_update(source_state, state)
+
+                if validate_each_source:
+                    if not source_state:
+                        continue
+                    try:
+                        _ = super(BaseSettings, self).__init__(**source_state)
+                    except ValidationError as e:
+                        line_errors = json.loads(e.json())
+                        for line in line_errors:
+                            ctx = line.get("ctx", {})
+                            ctx = {"source": source_name}
+                            line['ctx'] = ctx
+                        all_line_errors.extend(line_errors)
+
+            if all_line_errors and validate_each_source:
+                raise ValidationError.from_exception_data(
+                    title=self.__class__.__name__,
+                    line_errors=[InitErrorDetails(**l) for l in  all_line_errors],
+                    input_type="python"
+                )
             return state
         else:
             # no one should mean to do this, but I think returning an empty dict is marginally preferable

From 12d5537078f0e164b0ac63acbe6ccd26063eabf6 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 14:06:22 -0500
Subject: [PATCH 02/15] test source included in line_error context

---
 tests/test_settings.py | 26 +++++++++++++++++++++++++-
 1 file changed, 25 insertions(+), 1 deletion(-)

diff --git a/tests/test_settings.py b/tests/test_settings.py
index ba793a8e..917693b0 100644
--- a/tests/test_settings.py
+++ b/tests/test_settings.py
@@ -44,7 +44,7 @@
     NoDecode,
     PydanticBaseSettingsSource,
     SecretsSettingsSource,
-    SettingsConfigDict,
+    SettingsConfigDict
 )
 from pydantic_settings.sources import DefaultSettingsSource, SettingsError
 
@@ -1103,6 +1103,30 @@ class Settings(BaseSettings):
     ]
 
 
+def test_env_file_with_env_prefix_invalid_with_sources(tmp_path):
+    p = tmp_path / '.env'
+    p.write_text(prefix_test_env_invalid_file)
+
+    class Settings(BaseSettings):
+        a: str
+        b: str
+        c: str
+
+        model_config = SettingsConfigDict(env_file=p, env_prefix='prefix_', validate_each_source=True)
+
+    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',
+            'ctx': {'source': 'DotEnvSettingsSource'}
+        }
+    ]
+
+
 def test_ignore_env_file_with_env_prefix_invalid(tmp_path):
     p = tmp_path / '.env'
     p.write_text(prefix_test_env_invalid_file)

From fcc2329b135ee028490ebe258f350b96ad770da6 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 14:15:25 -0500
Subject: [PATCH 03/15] fix appending source to context

---
 pydantic_settings/main.py |  4 ++--
 tests/test_settings.py    | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index 1b1a22f1..974882c3 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -426,14 +426,14 @@ def _settings_build_values(
                         line_errors = json.loads(e.json())
                         for line in line_errors:
                             ctx = line.get("ctx", {})
-                            ctx = {"source": source_name}
+                            ctx["source"] = source_name
                             line['ctx'] = ctx
                         all_line_errors.extend(line_errors)
 
             if all_line_errors and validate_each_source:
                 raise ValidationError.from_exception_data(
                     title=self.__class__.__name__,
-                    line_errors=[InitErrorDetails(**l) for l in  all_line_errors],
+                    line_errors=[InitErrorDetails(**l) for l in all_line_errors],
                     input_type="python"
                 )
             return state
diff --git a/tests/test_settings.py b/tests/test_settings.py
index 917693b0..1a850cd7 100644
--- a/tests/test_settings.py
+++ b/tests/test_settings.py
@@ -472,6 +472,28 @@ class AnnotatedComplexSettings(BaseSettings):
     ]
 
 
+def test_annotated_list_with_error_source(env):
+    class AnnotatedComplexSettings(BaseSettings, validate_each_source=True):
+        apples: Annotated[List[str], MinLen(2)] = []
+
+    env.set('apples', '["russet", "granny smith"]')
+    s = AnnotatedComplexSettings()
+    assert s.apples == ['russet', 'granny smith']
+
+    env.set('apples', '["russet"]')
+    with pytest.raises(ValidationError) as exc_info:
+        AnnotatedComplexSettings()
+    assert exc_info.value.errors(include_url=False) == [
+        {
+            'ctx': {'actual_length': 1, 'field_type': 'List', 'min_length': 2, 'source': 'EnvSettingsSource'},
+            'input': ['russet'],
+            'loc': ('apples',),
+            'msg': 'List should have at least 2 items after validation, not 1',
+            'type': 'too_short',
+        }
+    ]
+
+
 def test_set_dict_model(env):
     env.set('bananas', '[1, 2, 3, 3]')
     env.set('CARROTS', '{"a": null, "b": 4}')

From 38e94de216b8a7d093c3d93ed8b500131926562c Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 14:40:21 -0500
Subject: [PATCH 04/15] validate for missing using full state

---
 pydantic_settings/main.py | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index 974882c3..c18bb9b0 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -405,7 +405,7 @@ def _settings_build_values(
         if sources:
             state: dict[str, Any] = {}
             states: dict[str, dict[str, Any]] = {}
-            all_line_errors: list[dict[str, Any]] = []
+            all_line_errors: list[InitErrorDetails] = []
             for source in sources:
                 if isinstance(source, PydanticBaseSettingsSource):
                     source._set_current_state(state)
@@ -425,16 +425,29 @@ def _settings_build_values(
                     except ValidationError as e:
                         line_errors = json.loads(e.json())
                         for line in line_errors:
+                            if line.get("type", "") == "missing":
+                                continue
                             ctx = line.get("ctx", {})
                             ctx["source"] = source_name
                             line['ctx'] = ctx
-                        all_line_errors.extend(line_errors)
+                            details = InitErrorDetails(**line)
+                            all_line_errors.append(details)
+
+            if validate_each_source:
+                try:
+                    _ = super(BaseSettings, self).__init__(**state)
+                except ValidationError as e:
+                    line_errors = json.loads(e.json())
+                    for line in line_errors:
+                        if line.get("type", "") != "missing":
+                            continue
+                        details = InitErrorDetails(**line)
+                        all_line_errors.append(details)
 
             if all_line_errors and validate_each_source:
                 raise ValidationError.from_exception_data(
                     title=self.__class__.__name__,
-                    line_errors=[InitErrorDetails(**l) for l in all_line_errors],
-                    input_type="python"
+                    line_errors=all_line_errors
                 )
             return state
         else:

From 6232d4d58a453542c6d873e305ddde1eb6fe9b86 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 14:40:39 -0500
Subject: [PATCH 05/15] test multi-source validation

and include missing fields
---
 tests/test_multi_source.py | 87 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 tests/test_multi_source.py

diff --git a/tests/test_multi_source.py b/tests/test_multi_source.py
new file mode 100644
index 00000000..616cbe09
--- /dev/null
+++ b/tests/test_multi_source.py
@@ -0,0 +1,87 @@
+"""
+Integration tests with multiple sources
+"""
+
+from typing import Tuple, Type, Union
+
+from pydantic import BaseModel, ValidationError
+import pytest
+
+from pydantic_settings import (
+    BaseSettings,
+    JsonConfigSettingsSource,
+    PydanticBaseSettingsSource,
+    SettingsConfigDict,
+)
+
+def test_line_errors_from_source(monkeypatch, tmp_path):
+    monkeypatch.setenv("SETTINGS_NESTED__NESTED_FIELD", "a")
+    p = tmp_path / 'settings.json'
+    p.write_text(
+        """
+    {"foobar": 0, "null_field": null}
+    """
+    )
+
+    class Nested(BaseModel):
+        nested_field: int
+
+    class Settings(BaseSettings):
+        model_config = SettingsConfigDict(
+            json_file=p,
+            env_prefix="SETTINGS_",
+            env_nested_delimiter="__",
+            validate_each_source=True
+        )
+        foobar: str
+        nested: Nested
+        null_field: Union[str, None]
+        extra: bool
+
+        @classmethod
+        def settings_customise_sources(
+            cls,
+            settings_cls: Type[BaseSettings],
+            init_settings: PydanticBaseSettingsSource,
+            env_settings: PydanticBaseSettingsSource,
+            dotenv_settings: PydanticBaseSettingsSource,
+            file_secret_settings: PydanticBaseSettingsSource,
+        ) -> Tuple[PydanticBaseSettingsSource, ...]:
+            return (
+                JsonConfigSettingsSource(settings_cls),
+                env_settings,
+                init_settings
+            )
+
+    with pytest.raises(ValidationError) as exc_info:
+        _ = Settings(null_field=0)
+
+    assert exc_info.value.errors(include_url=False) == [
+        {
+            'ctx': {'source': 'JsonConfigSettingsSource'},
+            'input': 0,
+            'loc': ('foobar',),
+            'msg': 'Input should be a valid string',
+            'type': 'string_type',
+        },
+        {
+            'ctx': {'source': 'EnvSettingsSource'},
+            'input': 'a',
+            'loc': ('nested', 'nested_field'),
+            'msg': 'Input should be a valid integer, unable to parse string as an integer',
+            'type': 'int_parsing'
+        },
+        {
+            'ctx': {'source': 'InitSettingsSource'},
+            'input': 0,
+            'loc': ('null_field',),
+            'msg': 'Input should be a valid string',
+            'type': 'string_type'
+        },
+        {
+            'input': {'foobar': 0, 'nested': {'nested_field': 'a'}, 'null_field': None},
+            'loc': ('extra',),
+            'msg': 'Field required',
+            'type': 'missing'
+        }
+    ]

From 590525f04c8e7ecbc8097fc6ebd42a1e2017159c Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:16:57 -0500
Subject: [PATCH 06/15] prepend source to loc field

---
 pydantic_settings/main.py  | 4 +---
 tests/test_multi_source.py | 9 +++------
 tests/test_settings.py     | 9 ++++-----
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index c18bb9b0..774d3e6a 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -427,9 +427,7 @@ def _settings_build_values(
                         for line in line_errors:
                             if line.get("type", "") == "missing":
                                 continue
-                            ctx = line.get("ctx", {})
-                            ctx["source"] = source_name
-                            line['ctx'] = ctx
+                            line['loc'] = [source_name] + line['loc']
                             details = InitErrorDetails(**line)
                             all_line_errors.append(details)
 
diff --git a/tests/test_multi_source.py b/tests/test_multi_source.py
index 616cbe09..ba796422 100644
--- a/tests/test_multi_source.py
+++ b/tests/test_multi_source.py
@@ -58,23 +58,20 @@ def settings_customise_sources(
 
     assert exc_info.value.errors(include_url=False) == [
         {
-            'ctx': {'source': 'JsonConfigSettingsSource'},
             'input': 0,
-            'loc': ('foobar',),
+            'loc': ('JsonConfigSettingsSource', 'foobar',),
             'msg': 'Input should be a valid string',
             'type': 'string_type',
         },
         {
-            'ctx': {'source': 'EnvSettingsSource'},
             'input': 'a',
-            'loc': ('nested', 'nested_field'),
+            'loc': ('EnvSettingsSource', 'nested', 'nested_field'),
             'msg': 'Input should be a valid integer, unable to parse string as an integer',
             'type': 'int_parsing'
         },
         {
-            'ctx': {'source': 'InitSettingsSource'},
             'input': 0,
-            'loc': ('null_field',),
+            'loc': ('InitSettingsSource', 'null_field',),
             'msg': 'Input should be a valid string',
             'type': 'string_type'
         },
diff --git a/tests/test_settings.py b/tests/test_settings.py
index 1a850cd7..6c921e83 100644
--- a/tests/test_settings.py
+++ b/tests/test_settings.py
@@ -485,9 +485,9 @@ class AnnotatedComplexSettings(BaseSettings, validate_each_source=True):
         AnnotatedComplexSettings()
     assert exc_info.value.errors(include_url=False) == [
         {
-            'ctx': {'actual_length': 1, 'field_type': 'List', 'min_length': 2, 'source': 'EnvSettingsSource'},
+            'ctx': {'actual_length': 1, 'field_type': 'List', 'min_length': 2},
             'input': ['russet'],
-            'loc': ('apples',),
+            'loc': ('EnvSettingsSource', 'apples',),
             'msg': 'List should have at least 2 items after validation, not 1',
             'type': 'too_short',
         }
@@ -1141,10 +1141,9 @@ class Settings(BaseSettings):
     assert exc_info.value.errors(include_url=False) == [
         {
             'type': 'extra_forbidden',
-            'loc': ('f',),
+            'loc': ('DotEnvSettingsSource', 'f',),
             'msg': 'Extra inputs are not permitted',
-            'input': 'random value',
-            'ctx': {'source': 'DotEnvSettingsSource'}
+            'input': 'random value'
         }
     ]
 

From 5497ab2857784deb39c4465f0f96088c3907f071 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:21:30 -0500
Subject: [PATCH 07/15] correction, let's keep source in ctx

---
 pydantic_settings/main.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index 774d3e6a..e6f9a83b 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -428,6 +428,9 @@ def _settings_build_values(
                             if line.get("type", "") == "missing":
                                 continue
                             line['loc'] = [source_name] + line['loc']
+                            ctx = line.get("ctx", {})
+                            ctx["source"] = source_name
+                            line['ctx'] = ctx
                             details = InitErrorDetails(**line)
                             all_line_errors.append(details)
 

From f90635271fe14331e3c6080ce210e96157104d32 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:23:25 -0500
Subject: [PATCH 08/15] and the tests

---
 tests/test_multi_source.py | 3 +++
 tests/test_settings.py     | 5 +++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/tests/test_multi_source.py b/tests/test_multi_source.py
index ba796422..9e47b8cb 100644
--- a/tests/test_multi_source.py
+++ b/tests/test_multi_source.py
@@ -58,18 +58,21 @@ def settings_customise_sources(
 
     assert exc_info.value.errors(include_url=False) == [
         {
+            'ctx': {'source': 'JsonConfigSettingsSource'},
             'input': 0,
             'loc': ('JsonConfigSettingsSource', 'foobar',),
             'msg': 'Input should be a valid string',
             'type': 'string_type',
         },
         {
+            'ctx': {'source': 'EnvSettingsSource'},
             'input': 'a',
             'loc': ('EnvSettingsSource', 'nested', 'nested_field'),
             'msg': 'Input should be a valid integer, unable to parse string as an integer',
             'type': 'int_parsing'
         },
         {
+            'ctx': {'source': 'InitSettingsSource'},
             'input': 0,
             'loc': ('InitSettingsSource', 'null_field',),
             'msg': 'Input should be a valid string',
diff --git a/tests/test_settings.py b/tests/test_settings.py
index 6c921e83..c5620c3c 100644
--- a/tests/test_settings.py
+++ b/tests/test_settings.py
@@ -485,7 +485,7 @@ class AnnotatedComplexSettings(BaseSettings, validate_each_source=True):
         AnnotatedComplexSettings()
     assert exc_info.value.errors(include_url=False) == [
         {
-            'ctx': {'actual_length': 1, 'field_type': 'List', 'min_length': 2},
+            'ctx': {'actual_length': 1, 'field_type': 'List', 'min_length': 2, 'source': 'EnvSettingsSource'},
             'input': ['russet'],
             'loc': ('EnvSettingsSource', 'apples',),
             'msg': 'List should have at least 2 items after validation, not 1',
@@ -1143,7 +1143,8 @@ class Settings(BaseSettings):
             'type': 'extra_forbidden',
             'loc': ('DotEnvSettingsSource', 'f',),
             'msg': 'Extra inputs are not permitted',
-            'input': 'random value'
+            'input': 'random value',
+            'ctx': {'source': 'DotEnvSettingsSource'}
         }
     ]
 

From 8a5e773f2873a79b11f7914edf07f5d4f5e2061a Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:31:56 -0500
Subject: [PATCH 09/15] fix super

---
 pydantic_settings/main.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index e6f9a83b..ca106fe6 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -421,7 +421,7 @@ def _settings_build_values(
                     if not source_state:
                         continue
                     try:
-                        _ = super(BaseSettings, self).__init__(**source_state)
+                        _ = super().__init__(**source_state)
                     except ValidationError as e:
                         line_errors = json.loads(e.json())
                         for line in line_errors:
@@ -436,7 +436,7 @@ def _settings_build_values(
 
             if validate_each_source:
                 try:
-                    _ = super(BaseSettings, self).__init__(**state)
+                    _ = super().__init__(**state)
                 except ValidationError as e:
                     line_errors = json.loads(e.json())
                     for line in line_errors:

From 063b71d9e5704d88746f12f880da11c500eec8e5 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:34:42 -0500
Subject: [PATCH 10/15] unnecessary use of initerrordetails

---
 pydantic_settings/main.py | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index ca106fe6..2aa17d45 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -431,8 +431,7 @@ def _settings_build_values(
                             ctx = line.get("ctx", {})
                             ctx["source"] = source_name
                             line['ctx'] = ctx
-                            details = InitErrorDetails(**line)
-                            all_line_errors.append(details)
+                            all_line_errors.append(line)
 
             if validate_each_source:
                 try:
@@ -442,8 +441,7 @@ def _settings_build_values(
                     for line in line_errors:
                         if line.get("type", "") != "missing":
                             continue
-                        details = InitErrorDetails(**line)
-                        all_line_errors.append(details)
+                        all_line_errors.append(line)
 
             if all_line_errors and validate_each_source:
                 raise ValidationError.from_exception_data(

From 8cf446231424ea25e8eede22c169d1b259ac0a39 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:36:53 -0500
Subject: [PATCH 11/15] single quotes

---
 pydantic_settings/main.py  | 8 ++++----
 tests/test_multi_source.py | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index 2aa17d45..b37cb288 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -425,11 +425,11 @@ def _settings_build_values(
                     except ValidationError as e:
                         line_errors = json.loads(e.json())
                         for line in line_errors:
-                            if line.get("type", "") == "missing":
+                            if line.get("type", "") == 'missing':
                                 continue
                             line['loc'] = [source_name] + line['loc']
-                            ctx = line.get("ctx", {})
-                            ctx["source"] = source_name
+                            ctx = line.get('ctx', {})
+                            ctx['source'] = source_name
                             line['ctx'] = ctx
                             all_line_errors.append(line)
 
@@ -439,7 +439,7 @@ def _settings_build_values(
                 except ValidationError as e:
                     line_errors = json.loads(e.json())
                     for line in line_errors:
-                        if line.get("type", "") != "missing":
+                        if line.get('type', '') != 'missing':
                             continue
                         all_line_errors.append(line)
 
diff --git a/tests/test_multi_source.py b/tests/test_multi_source.py
index 9e47b8cb..f8a60f24 100644
--- a/tests/test_multi_source.py
+++ b/tests/test_multi_source.py
@@ -15,7 +15,7 @@
 )
 
 def test_line_errors_from_source(monkeypatch, tmp_path):
-    monkeypatch.setenv("SETTINGS_NESTED__NESTED_FIELD", "a")
+    monkeypatch.setenv('SETTINGS_NESTED__NESTED_FIELD', 'a')
     p = tmp_path / 'settings.json'
     p.write_text(
         """
@@ -29,8 +29,8 @@ class Nested(BaseModel):
     class Settings(BaseSettings):
         model_config = SettingsConfigDict(
             json_file=p,
-            env_prefix="SETTINGS_",
-            env_nested_delimiter="__",
+            env_prefix='SETTINGS_',
+            env_nested_delimiter='__',
             validate_each_source=True
         )
         foobar: str

From e9467af90f87773469c6a4d8afe862efa4b4a1e2 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Wed, 19 Feb 2025 15:37:27 -0500
Subject: [PATCH 12/15] one more

---
 pydantic_settings/main.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index b37cb288..b66cc11e 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -335,7 +335,7 @@ def _settings_build_values(
 
         secrets_dir = _secrets_dir if _secrets_dir is not None else self.model_config.get('secrets_dir')
 
-        validate_each_source = _validate_each_source if _validate_each_source is not None else self.model_config.get("validate_each_source")
+        validate_each_source = _validate_each_source if _validate_each_source is not None else self.model_config.get('validate_each_source')
 
         # Configure built-in sources
         default_settings = DefaultSettingsSource(

From 577ca8e9129754026483fea38e75c2c5dd4b15a5 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Thu, 20 Feb 2025 09:30:32 -0500
Subject: [PATCH 13/15] lint and reduce complexity

---
 pydantic_settings/main.py | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index b66cc11e..fa6d0735 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -14,7 +14,7 @@
 from pydantic._internal._utils import deep_update, is_model_class
 from pydantic.dataclasses import is_pydantic_dataclass
 from pydantic.main import BaseModel
-from pydantic_core import ValidationError, InitErrorDetails
+from pydantic_core import InitErrorDetails, ValidationError
 
 from .sources import (
     ENV_FILE_SENTINEL,
@@ -417,15 +417,13 @@ def _settings_build_values(
                 states[source_name] = source_state
                 state = deep_update(source_state, state)
 
-                if validate_each_source:
-                    if not source_state:
-                        continue
+                if source_state and validate_each_source:
                     try:
                         _ = super().__init__(**source_state)
                     except ValidationError as e:
                         line_errors = json.loads(e.json())
                         for line in line_errors:
-                            if line.get("type", "") == 'missing':
+                            if line.get('type', '') == 'missing':
                                 continue
                             line['loc'] = [source_name] + line['loc']
                             ctx = line.get('ctx', {})
@@ -438,16 +436,14 @@ def _settings_build_values(
                     _ = super().__init__(**state)
                 except ValidationError as e:
                     line_errors = json.loads(e.json())
-                    for line in line_errors:
-                        if line.get('type', '') != 'missing':
-                            continue
-                        all_line_errors.append(line)
-
-            if all_line_errors and validate_each_source:
-                raise ValidationError.from_exception_data(
-                    title=self.__class__.__name__,
-                    line_errors=all_line_errors
-                )
+                    all_line_errors.extend([line for line in line_errors if line.get('type', '') == 'missing'])
+
+                if all_line_errors:
+                    raise ValidationError.from_exception_data(
+                        title=self.__class__.__name__,
+                        line_errors=all_line_errors
+                    )
+
             return state
         else:
             # no one should mean to do this, but I think returning an empty dict is marginally preferable

From 4d13cd7e108515144ac2a89104a59e1dcb262558 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Thu, 20 Feb 2025 09:31:34 -0500
Subject: [PATCH 14/15] lint tests

---
 tests/test_multi_source.py | 3 ++-
 tests/test_settings.py     | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/tests/test_multi_source.py b/tests/test_multi_source.py
index f8a60f24..49a670bd 100644
--- a/tests/test_multi_source.py
+++ b/tests/test_multi_source.py
@@ -4,8 +4,8 @@
 
 from typing import Tuple, Type, Union
 
-from pydantic import BaseModel, ValidationError
 import pytest
+from pydantic import BaseModel, ValidationError
 
 from pydantic_settings import (
     BaseSettings,
@@ -14,6 +14,7 @@
     SettingsConfigDict,
 )
 
+
 def test_line_errors_from_source(monkeypatch, tmp_path):
     monkeypatch.setenv('SETTINGS_NESTED__NESTED_FIELD', 'a')
     p = tmp_path / 'settings.json'
diff --git a/tests/test_settings.py b/tests/test_settings.py
index c5620c3c..301c09ef 100644
--- a/tests/test_settings.py
+++ b/tests/test_settings.py
@@ -44,7 +44,7 @@
     NoDecode,
     PydanticBaseSettingsSource,
     SecretsSettingsSource,
-    SettingsConfigDict
+    SettingsConfigDict,
 )
 from pydantic_settings.sources import DefaultSettingsSource, SettingsError
 

From 9842e13f4c339e6289d032ead4528fcb12567aa9 Mon Sep 17 00:00:00 2001
From: Albert DeFusco <adefusco@anaconda.com>
Date: Thu, 20 Feb 2025 09:35:28 -0500
Subject: [PATCH 15/15] formatting with ruff

---
 pydantic_settings/main.py    | 12 ++++++++----
 pydantic_settings/sources.py |  8 +++++---
 tests/test_multi_source.py   | 29 ++++++++++++++---------------
 tests/test_settings.py       | 15 ++++++++++-----
 4 files changed, 37 insertions(+), 27 deletions(-)

diff --git a/pydantic_settings/main.py b/pydantic_settings/main.py
index fa6d0735..8c716cc8 100644
--- a/pydantic_settings/main.py
+++ b/pydantic_settings/main.py
@@ -34,6 +34,7 @@
 
 T = TypeVar('T')
 
+
 class SettingsConfigDict(ConfigDict, total=False):
     case_sensitive: bool
     nested_model_default_partial_update: bool | None
@@ -259,7 +260,7 @@ def _settings_build_values(
         _cli_ignore_unknown_args: bool | None = None,
         _cli_kebab_case: bool | None = None,
         _secrets_dir: PathType | None = None,
-        _validate_each_source: bool | None = None
+        _validate_each_source: bool | None = None,
     ) -> dict[str, Any]:
         # Determine settings config values
         case_sensitive = _case_sensitive if _case_sensitive is not None else self.model_config.get('case_sensitive')
@@ -335,7 +336,11 @@ def _settings_build_values(
 
         secrets_dir = _secrets_dir if _secrets_dir is not None else self.model_config.get('secrets_dir')
 
-        validate_each_source = _validate_each_source if _validate_each_source is not None else self.model_config.get('validate_each_source')
+        validate_each_source = (
+            _validate_each_source
+            if _validate_each_source is not None
+            else self.model_config.get('validate_each_source')
+        )
 
         # Configure built-in sources
         default_settings = DefaultSettingsSource(
@@ -440,8 +445,7 @@ def _settings_build_values(
 
                 if all_line_errors:
                     raise ValidationError.from_exception_data(
-                        title=self.__class__.__name__,
-                        line_errors=all_line_errors
+                        title=self.__class__.__name__, line_errors=all_line_errors
                     )
 
             return state
diff --git a/pydantic_settings/sources.py b/pydantic_settings/sources.py
index bd4f4315..c929fe86 100644
--- a/pydantic_settings/sources.py
+++ b/pydantic_settings/sources.py
@@ -1785,11 +1785,13 @@ def _add_parser_args(
                         if isinstance(group, dict):
                             group = self._add_group(parser, **group)
                         added_args += list(arg_names)
-                        self._add_argument(group, *(f'{flag_prefix[:len(name)]}{name}' for name in arg_names), **kwargs)
+                        self._add_argument(
+                            group, *(f'{flag_prefix[: len(name)]}{name}' for name in arg_names), **kwargs
+                        )
                     else:
                         added_args += list(arg_names)
                         self._add_argument(
-                            parser, *(f'{flag_prefix[:len(name)]}{name}' for name in arg_names), **kwargs
+                            parser, *(f'{flag_prefix[: len(name)]}{name}' for name in arg_names), **kwargs
                         )
 
         self._add_parser_alias_paths(parser, alias_path_args, added_args, arg_prefix, subcommand_prefix, group)
@@ -2246,7 +2248,7 @@ def _load_env_vars(self) -> Mapping[str, Optional[str]]:
         return AzureKeyVaultMapping(secret_client)
 
     def __repr__(self) -> str:
-        return f'{self.__class__.__name__}(url={self._url!r}, ' f'env_nested_delimiter={self.env_nested_delimiter!r})'
+        return f'{self.__class__.__name__}(url={self._url!r}, env_nested_delimiter={self.env_nested_delimiter!r})'
 
 
 def _get_env_var_key(key: str, case_sensitive: bool = False) -> str:
diff --git a/tests/test_multi_source.py b/tests/test_multi_source.py
index 49a670bd..5e2a800c 100644
--- a/tests/test_multi_source.py
+++ b/tests/test_multi_source.py
@@ -29,10 +29,7 @@ class Nested(BaseModel):
 
     class Settings(BaseSettings):
         model_config = SettingsConfigDict(
-            json_file=p,
-            env_prefix='SETTINGS_',
-            env_nested_delimiter='__',
-            validate_each_source=True
+            json_file=p, env_prefix='SETTINGS_', env_nested_delimiter='__', validate_each_source=True
         )
         foobar: str
         nested: Nested
@@ -48,11 +45,7 @@ def settings_customise_sources(
             dotenv_settings: PydanticBaseSettingsSource,
             file_secret_settings: PydanticBaseSettingsSource,
         ) -> Tuple[PydanticBaseSettingsSource, ...]:
-            return (
-                JsonConfigSettingsSource(settings_cls),
-                env_settings,
-                init_settings
-            )
+            return (JsonConfigSettingsSource(settings_cls), env_settings, init_settings)
 
     with pytest.raises(ValidationError) as exc_info:
         _ = Settings(null_field=0)
@@ -61,7 +54,10 @@ def settings_customise_sources(
         {
             'ctx': {'source': 'JsonConfigSettingsSource'},
             'input': 0,
-            'loc': ('JsonConfigSettingsSource', 'foobar',),
+            'loc': (
+                'JsonConfigSettingsSource',
+                'foobar',
+            ),
             'msg': 'Input should be a valid string',
             'type': 'string_type',
         },
@@ -70,19 +66,22 @@ def settings_customise_sources(
             'input': 'a',
             'loc': ('EnvSettingsSource', 'nested', 'nested_field'),
             'msg': 'Input should be a valid integer, unable to parse string as an integer',
-            'type': 'int_parsing'
+            'type': 'int_parsing',
         },
         {
             'ctx': {'source': 'InitSettingsSource'},
             'input': 0,
-            'loc': ('InitSettingsSource', 'null_field',),
+            'loc': (
+                'InitSettingsSource',
+                'null_field',
+            ),
             'msg': 'Input should be a valid string',
-            'type': 'string_type'
+            'type': 'string_type',
         },
         {
             'input': {'foobar': 0, 'nested': {'nested_field': 'a'}, 'null_field': None},
             'loc': ('extra',),
             'msg': 'Field required',
-            'type': 'missing'
-        }
+            'type': 'missing',
+        },
     ]
diff --git a/tests/test_settings.py b/tests/test_settings.py
index 301c09ef..190be2f9 100644
--- a/tests/test_settings.py
+++ b/tests/test_settings.py
@@ -487,7 +487,10 @@ class AnnotatedComplexSettings(BaseSettings, validate_each_source=True):
         {
             'ctx': {'actual_length': 1, 'field_type': 'List', 'min_length': 2, 'source': 'EnvSettingsSource'},
             'input': ['russet'],
-            'loc': ('EnvSettingsSource', 'apples',),
+            'loc': (
+                'EnvSettingsSource',
+                'apples',
+            ),
             'msg': 'List should have at least 2 items after validation, not 1',
             'type': 'too_short',
         }
@@ -1141,10 +1144,13 @@ class Settings(BaseSettings):
     assert exc_info.value.errors(include_url=False) == [
         {
             'type': 'extra_forbidden',
-            'loc': ('DotEnvSettingsSource', 'f',),
+            'loc': (
+                'DotEnvSettingsSource',
+                'f',
+            ),
             'msg': 'Extra inputs are not permitted',
             'input': 'random value',
-            'ctx': {'source': 'DotEnvSettingsSource'}
+            'ctx': {'source': 'DotEnvSettingsSource'},
         }
     ]
 
@@ -1925,8 +1931,7 @@ def test_builtins_settings_source_repr():
         == "EnvSettingsSource(env_nested_delimiter='__', env_prefix_len=0)"
     )
     assert repr(DotEnvSettingsSource(BaseSettings, env_file='.env', env_file_encoding='utf-8')) == (
-        "DotEnvSettingsSource(env_file='.env', env_file_encoding='utf-8', "
-        'env_nested_delimiter=None, env_prefix_len=0)'
+        "DotEnvSettingsSource(env_file='.env', env_file_encoding='utf-8', env_nested_delimiter=None, env_prefix_len=0)"
     )
     assert (
         repr(SecretsSettingsSource(BaseSettings, secrets_dir='/secrets'))