utils.serialize: lazy imports (#5224)

dvc/utils/serialize/_common.py

@@ -6,7 +6,6 @@ from typing import TYPE_CHECKING, Any, Callable, ContextManager, Dict, Union
 from typing_extensions import Protocol
 
 from dvc.exceptions import DvcException
-from dvc.utils import relpath
 
 if TYPE_CHECKING:
     from dvc.tree.base import BaseTree
@@ -40,6 +39,8 @@ class ParseError(DvcException):
     """Errors while parsing files"""
 
     def __init__(self, path: "AnyPath", message: str):
+        from dvc.utils import relpath
+
         path = relpath(path)
         super().__init__(f"unable to read: '{path}', {message}")
 

dvc/utils/serialize/_toml.py

@@ -1,6 +1,5 @@
 from contextlib import contextmanager
 
-import toml
 from funcy import reraise
 
 from ._common import ParseError, _dump_data, _load_data, _modify_data
@@ -16,8 +15,10 @@ def load_toml(path, tree=None):
 
 
 def parse_toml(text, path, decoder=None):
-    with reraise(toml.TomlDecodeError, TOMLFileCorruptedError(path)):
-        return toml.loads(text, decoder=decoder)
+    from toml import TomlDecodeError, loads
+
+    with reraise(TomlDecodeError, TOMLFileCorruptedError(path)):
+        return loads(text, decoder=decoder)
 
 
 def parse_toml_for_update(text, path):
@@ -27,11 +28,15 @@ def parse_toml_for_update(text, path):
     keys may be re-ordered between load/dump, but this function will at
     least preserve comments.
     """
-    decoder = toml.TomlPreserveCommentDecoder()
+    from toml import TomlPreserveCommentDecoder
+
+    decoder = TomlPreserveCommentDecoder()
     return parse_toml(text, path, decoder=decoder)
 
 
 def _dump(data, stream):
+    import toml
+
     return toml.dump(data, stream, encoder=toml.TomlPreserveCommentEncoder())
 
 

dvc/utils/serialize/_yaml.py

@@ -3,9 +3,6 @@ from collections import OrderedDict
 from contextlib import contextmanager
 
 from funcy import reraise
-from ruamel.yaml import YAML
-from ruamel.yaml.constructor import DuplicateKeyError
-from ruamel.yaml.error import YAMLError as _YAMLError
 
 from ._common import ParseError, _dump_data, _load_data, _modify_data
 
@@ -24,6 +21,10 @@ def load_yaml(path, tree=None):
 
 
 def parse_yaml(text, path, typ="safe"):
+    from ruamel.yaml import YAML
+    from ruamel.yaml import YAMLError as _YAMLError
+    from ruamel.yaml.constructor import DuplicateKeyError
+
     yaml = YAML(typ=typ)
     try:
         with reraise(_YAMLError, YAMLFileCorruptedError(path)):
@@ -48,6 +49,8 @@ def parse_yaml_for_update(text, path):
 
 
 def _get_yaml():
+    from ruamel.yaml import YAML
+
     yaml = YAML()
     yaml.default_flow_style = False
 
@@ -67,6 +70,8 @@ def dump_yaml(path, data, tree=None):
 
 
 def loads_yaml(s, typ="safe"):
+    from ruamel.yaml import YAML
+
     return YAML(typ=typ).load(s)