I gang

venv/lib/python3.12/site-packages/pydantic_settings/sources/providers/yaml.py

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+"""YAML file settings source."""
+
+from __future__ import annotations as _annotations
+
+from pathlib import Path
+from typing import (
+    TYPE_CHECKING,
+    Any,
+)
+
+from ..base import ConfigFileSourceMixin, InitSettingsSource
+from ..types import DEFAULT_PATH, PathType
+
+if TYPE_CHECKING:
+    import yaml
+
+    from pydantic_settings.main import BaseSettings
+else:
+    yaml = None
+
+
+def import_yaml() -> None:
+    global yaml
+    if yaml is not None:
+        return
+    try:
+        import yaml
+    except ImportError as e:
+        raise ImportError('PyYAML is not installed, run `pip install pydantic-settings[yaml]`') from e
+
+
+class YamlConfigSettingsSource(InitSettingsSource, ConfigFileSourceMixin):
+    """
+    A source class that loads variables from a yaml file
+    """
+
+    def __init__(
+        self,
+        settings_cls: type[BaseSettings],
+        yaml_file: PathType | None = DEFAULT_PATH,
+        yaml_file_encoding: str | None = None,
+        yaml_config_section: str | None = None,
+        deep_merge: bool = False,
+    ):
+        self.yaml_file_path = yaml_file if yaml_file != DEFAULT_PATH else settings_cls.model_config.get('yaml_file')
+        self.yaml_file_encoding = (
+            yaml_file_encoding
+            if yaml_file_encoding is not None
+            else settings_cls.model_config.get('yaml_file_encoding')
+        )
+        self.yaml_config_section = (
+            yaml_config_section
+            if yaml_config_section is not None
+            else settings_cls.model_config.get('yaml_config_section')
+        )
+        self.yaml_data = self._read_files(self.yaml_file_path, deep_merge=deep_merge)
+
+        if self.yaml_config_section is not None:
+            self.yaml_data = self._traverse_nested_section(
+                self.yaml_data, self.yaml_config_section, self.yaml_config_section
+            )
+        super().__init__(settings_cls, self.yaml_data)
+
+    def _read_file(self, file_path: Path) -> dict[str, Any]:
+        import_yaml()
+        with file_path.open(encoding=self.yaml_file_encoding) as yaml_file:
+            return yaml.safe_load(yaml_file) or {}
+
+    def _traverse_nested_section(
+        self, data: dict[str, Any], section_path: str, original_path: str | None = None
+    ) -> dict[str, Any]:
+        """
+        Traverse nested YAML sections using dot-notation path.
+
+        This method tries to match the longest possible key first before splitting on dots,
+        allowing access to YAML keys that contain literal dot characters.
+
+        For example, with section_path="a.b.c", it will try:
+        1. "a.b.c" as a literal key
+        2. "a.b" as a key, then traverse to "c"
+        3. "a" as a key, then traverse to "b.c"
+        4. "a" as a key, then "b" as a key, then "c" as a key
+        """
+        # Track the original path for error messages
+        if original_path is None:
+            original_path = section_path
+
+        # Only reject truly empty paths
+        if not section_path:
+            raise ValueError('yaml_config_section cannot be empty')
+
+        # Try the full path as a literal key first (even with leading/trailing/consecutive dots)
+        try:
+            return data[section_path]
+        except KeyError:
+            pass  # Not a literal key, try splitting
+        except TypeError:
+            raise TypeError(
+                f'yaml_config_section path "{original_path}" cannot be traversed in {self.yaml_file_path}. '
+                f'An intermediate value is not a dictionary.'
+            )
+
+        # If path contains no dots, we already tried it as a literal key above
+        if '.' not in section_path:
+            raise KeyError(f'yaml_config_section key "{original_path}" not found in {self.yaml_file_path}')
+
+        # Try progressively shorter prefixes (greedy left-to-right approach)
+        parts = section_path.split('.')
+        for i in range(len(parts) - 1, 0, -1):
+            prefix = '.'.join(parts[:i])
+            suffix = '.'.join(parts[i:])
+
+            if prefix in data:
+                # Found the prefix as a literal key, now recursively traverse the suffix
+                try:
+                    return self._traverse_nested_section(data[prefix], suffix, original_path)
+                except TypeError:
+                    raise TypeError(
+                        f'yaml_config_section path "{original_path}" cannot be traversed in {self.yaml_file_path}. '
+                        f'An intermediate value is not a dictionary.'
+                    )
+
+        # If we get here, no match was found
+        raise KeyError(f'yaml_config_section key "{original_path}" not found in {self.yaml_file_path}')
+
+    def __repr__(self) -> str:
+        return f'{self.__class__.__name__}(yaml_file={self.yaml_file_path})'
+
+
+__all__ = ['YamlConfigSettingsSource']