Alllowi the delimiter to be included in the env_name

Author: gsakkis

pydantic_settings/sources.py

@@ -749,6 +749,7 @@ def __init__(
         self.env_nested_depth = (
             env_nested_depth if env_nested_depth is not None else self.config.get('env_nested_depth', -1)
         )
+        self.maxsplit = self.env_nested_depth - 1 if self.env_nested_depth > 0 else self.env_nested_depth
         self.env_prefix_len = len(self.env_prefix)
 
         self.env_vars = self._load_env_vars()
@@ -914,11 +915,13 @@ def explode_env_vars(self, field_name: str, field: FieldInfo, env_vars: Mapping[
         ]
         result: dict[str, Any] = {}
         for env_name, env_val in env_vars.items():
-            if not any(env_name.startswith(prefix) for prefix in prefixes):
+            try:
+                prefix = next(prefix for prefix in prefixes if env_name.startswith(prefix))
+            except StopIteration:
                 continue
             # we remove the prefix before splitting in case the prefix has characters in common with the delimiter
-            env_name_without_prefix = env_name[self.env_prefix_len :]
-            _, *keys, last_key = env_name_without_prefix.split(self.env_nested_delimiter, self.env_nested_depth)
+            env_name_without_prefix = env_name[len(prefix) :]
+            *keys, last_key = env_name_without_prefix.split(self.env_nested_delimiter, self.maxsplit)
             env_var = result
             target_field: FieldInfo | None = field
             for key in keys:

tests/test_settings.py

@@ -407,6 +407,8 @@ class Person(BaseModel):
 
     class Cfg(BaseSettings):
         caregiver: Person
+        significant_other: Optional[Person] = None
+        next_of_kin: Optional[Person] = None
 
         model_config = SettingsConfigDict(env_nested_delimiter='_', env_nested_depth=1)
         if env_prefix is not None:
@@ -416,9 +418,17 @@ class Cfg(BaseSettings):
     env.set(env_prefix + 'caregiver_sex', 'M')
     env.set(env_prefix + 'caregiver_first_name', 'Joe')
     env.set(env_prefix + 'caregiver_date_of_birth', '1975-09-12')
+    env.set(env_prefix + 'significant_other_sex', 'F')
+    env.set(env_prefix + 'significant_other_first_name', 'Jill')
+    env.set(env_prefix + 'significant_other_date_of_birth', '1998-04-19')
+    env.set(env_prefix + 'next_of_kin_sex', 'M')
+    env.set(env_prefix + 'next_of_kin_first_name', 'Jack')
+    env.set(env_prefix + 'next_of_kin_date_of_birth', '1999-04-19')
 
     assert Cfg().model_dump() == {
         'caregiver': {'sex': 'M', 'first_name': 'Joe', 'date_of_birth': date(1975, 9, 12)},
+        'significant_other': {'sex': 'F', 'first_name': 'Jill', 'date_of_birth': date(1998, 4, 19)},
+        'next_of_kin': {'sex': 'M', 'first_name': 'Jack', 'date_of_birth': date(1999, 4, 19)},
     }