Migrate from Pydantic v1 to native Pydantic v2

.github/workflows-config/python-versions.txt

@@ -1,6 +1,6 @@
-3.8
 3.9
 3.10
 3.11
 3.12
-3.13
+3.13
+3.14

.github/workflows/regression-testing.yml

@@ -23,7 +23,7 @@ jobs:
             echo "python=$(jq -Rsc 'split("\n") | map(select(length > 0))' .github/workflows-config/python-versions.txt)" >> $GITHUB_OUTPUT
             echo "os=$(jq -Rsc 'split("\n") | map(select(length > 0))' .github/workflows-config/os-versions.txt)" >> $GITHUB_OUTPUT
           else
-            echo 'python=["3.13"]' >> $GITHUB_OUTPUT
+            echo 'python=["3.14"]' >> $GITHUB_OUTPUT
             echo 'os=["ubuntu-24.04","macos-15","windows-latest"]' >> $GITHUB_OUTPUT
           fi
 

lean/commands/optimize.py

@@ -267,8 +267,8 @@ def optimize(project: Path,
                 "target": optimization_target.target,
                 "extremum": optimization_target.extremum.value
             },
-            "parameters": [parameter.dict() for parameter in optimization_parameters],
-            "constraints": [constraint.dict(by_alias=True) for constraint in optimization_constraints]
+            "parameters": [parameter.model_dump() for parameter in optimization_parameters],
+            "constraints": [constraint.model_dump(by_alias=True) for constraint in optimization_constraints]
         }
 
     if max_concurrent_backtests is not None:

lean/components/api/live_client.py

@@ -97,7 +97,7 @@ def start(self,
 
             parameters["notification"] = {
                 "events": events,
-                "targets": [{x: y for x, y in method.dict().items() if y} for method in notify_methods]
+                "targets": [{x: y for x, y in method.model_dump().items() if y} for method in notify_methods]
             }
 
         data = self._api.post("live/create", parameters)

lean/components/util/library_manager.py

@@ -119,11 +119,10 @@ def add_lean_library_reference_to_project(self, project_dir: Path, library_dir:
             raise RuntimeError("Circular dependency detected between "
                                f"{project_relative_path} and {library_relative_path}")
 
-        from json import loads
-        project_libraries.append(loads(LeanLibraryReference(
+        project_libraries.append(LeanLibraryReference(
             name=library_dir.name,
             path=library_relative_path
-        ).json()))
+        ).model_dump(mode="json"))
         project_config.set("libraries", project_libraries)
 
         return False

lean/models/api.py

@@ -15,15 +15,15 @@
 from enum import Enum
 from typing import Any, Dict, List, Optional, Union
 
-from lean.models.pydantic import WrappedBaseModel, validator
+from lean.models.pydantic import WrappedBaseModel, field_validator
 
 
 # The models in this module are all parts of responses from the QuantConnect API
 # The keys of properties are not changed, so they don't obey the rest of the project's naming conventions
 
 
 class QCAuth0Authorization(WrappedBaseModel):
-    authorization: Optional[Dict[str, Any]]
+    authorization: Optional[Dict[str, Any]] = None
 
     def get_account_ids(self) -> List[str]:
         """
@@ -55,7 +55,7 @@ class ProjectEncryptionKey(WrappedBaseModel):
     name: str
 
 class QCCollaborator(WrappedBaseModel):
-    uid: Optional[int]
+    uid: Optional[int] = None
     liveControl: bool
     permission: str
     profileImage: str
@@ -66,10 +66,10 @@ class QCCollaborator(WrappedBaseModel):
 class QCParameter(WrappedBaseModel):
     key: str
     value: str
-    min: Optional[float]
-    max: Optional[float]
-    step: Optional[float]
-    type: Optional[str]
+    min: Optional[float] = None
+    max: Optional[float] = None
+    step: Optional[float] = None
+    type: Optional[str] = None
 
 
 class QCLanguage(str, Enum):
@@ -112,7 +112,8 @@ class QCProject(WrappedBaseModel):
     encrypted: Optional[bool] = False
     encryptionKey: Optional[ProjectEncryptionKey] = None
 
-    @validator("parameters", pre=True)
+    @field_validator("parameters", mode="before")
+    @classmethod
     def process_parameters_dict(cls, value: Any) -> Any:
         if isinstance(value, dict):
             return list(value.values())
@@ -181,9 +182,9 @@ class QCBacktest(WrappedBaseModel):
     result: Optional[Any] = None
     error: Optional[str] = None
     stacktrace: Optional[str] = None
-    runtimeStatistics: Optional[Dict[str, str]]
-    statistics: Optional[Union[Dict[str, str], List[Any]]]
-    totalPerformance: Optional[Any]
+    runtimeStatistics: Optional[Dict[str, str]] = None
+    statistics: Optional[Union[Dict[str, str], List[Any]]] = None
+    totalPerformance: Optional[Any] = None
 
     def is_complete(self) -> bool:
         """Returns whether the backtest has completed in the cloud.
@@ -271,7 +272,7 @@ class QCNode(WrappedBaseModel):
     cpu: int
     ram: float
     assets: int
-    host: Optional[str]
+    host: Optional[str] = None
 
 
 class QCNodeList(WrappedBaseModel):
@@ -297,7 +298,7 @@ class QCLiveAlgorithmStatus(str, Enum):
 
 class QCRestResponse(WrappedBaseModel):
     success: bool
-    error: Optional[List[str]]
+    error: Optional[List[str]] = None
 
 class QCMinimalLiveAlgorithm(WrappedBaseModel):
     projectId: int
@@ -317,7 +318,7 @@ class QCFullLiveAlgorithm(QCMinimalLiveAlgorithm):
     deployId: str
     status: Optional[QCLiveAlgorithmStatus] = None
     launched: datetime
-    stopped: Optional[datetime]
+    stopped: Optional[datetime] = None
     brokerage: str
 
 
@@ -389,7 +390,7 @@ class QCOrganizationProduct(WrappedBaseModel):
 
 
 class QCOrganizationData(WrappedBaseModel):
-    signedTime: Optional[int]
+    signedTime: Optional[int] = None
     current: bool
 
 
@@ -544,7 +545,8 @@ class QCOptimization(WrappedBaseModel):
     backtests: Dict[str, QCOptimizationBacktest] = {}
     runtimeStatistics: Dict[str, str] = {}
 
-    @validator("backtests", "runtimeStatistics", pre=True)
+    @field_validator("backtests", "runtimeStatistics", mode="before")
+    @classmethod
     def parse_empty_lists(cls, value: Any) -> Any:
         # If these fields have no data, they are assigned an array by default
         # For consistency we convert those empty arrays to empty dicts
@@ -576,9 +578,10 @@ class QCDataVendor(WrappedBaseModel):
     regex: Any
 
     # Price in QCC
-    price: Optional[float]
+    price: Optional[float] = None
 
-    @validator("regex", pre=True)
+    @field_validator("regex", mode="before")
+    @classmethod
     def parse_regex(cls, value: Any) -> Any:
         from re import compile
         if isinstance(value, str):
@@ -614,7 +617,7 @@ class QCDataset(WrappedBaseModel):
 class QCUser(WrappedBaseModel):
     name: str
     profile: str
-    badge: Optional[str]
+    badge: Optional[str] = None
 
 
 class QCTerminalNewsItem(WrappedBaseModel):
@@ -625,15 +628,15 @@ class QCTerminalNewsItem(WrappedBaseModel):
     content: str
     image: str
     link: str
-    year_deleted: Optional[Any]
-    week_deleted: Optional[Any]
+    year_deleted: Optional[Any] = None
+    week_deleted: Optional[Any] = None
     created: datetime
     date: datetime
 
 
 class QCLeanEnvironment(WrappedBaseModel):
     id: int
     name: str
-    path: Optional[str]
+    path: Optional[str] = None
     description: str
     public: bool

lean/models/data.py

@@ -14,15 +14,16 @@
 from abc import ABC
 from datetime import datetime
 from enum import Enum
-from typing import List, Any, Optional, Dict, Set, Tuple, Pattern
+import re
+from typing import List, Any, Optional, Dict, Set, Tuple
 
 from click import prompt
 
 from lean.click import DateParameter
 from lean.container import container
 from lean.models.api import QCDataVendor
 from lean.models.logger import Option
-from lean.models.pydantic import WrappedBaseModel, validator
+from lean.models.pydantic import WrappedBaseModel, field_validator
 
 class OptionResult(WrappedBaseModel):
     """The OptionResult class represents an option's result with an internal value and a display-friendly label."""
@@ -84,7 +85,8 @@ class DatasetOption(WrappedBaseModel, ABC):
     description: str
     condition: Optional[DatasetCondition] = None
 
-    @validator("condition", pre=True)
+    @field_validator("condition", mode="before")
+    @classmethod
     def parse_condition(cls, value: Optional[Any]) -> Any:
         if value is None or isinstance(value, DatasetCondition):
             return value
@@ -258,7 +260,8 @@ class DatasetPath(WrappedBaseModel):
     condition: Optional[DatasetCondition] = None
     templates: DatasetPathTemplates
 
-    @validator("condition", pre=True)
+    @field_validator("condition", mode="before")
+    @classmethod
     def parse_condition(cls, value: Optional[Any]) -> Any:
         if value is None or isinstance(value, DatasetCondition):
             return value
@@ -290,7 +293,8 @@ class Dataset(WrappedBaseModel):
     paths: List[DatasetPath]
     requirements: Dict[int, str]
 
-    @validator("options", pre=True)
+    @field_validator("options", mode="before")
+    @classmethod
     def parse_options(cls, values: List[Any]) -> List[Any]:
         option_types = {
             "text": DatasetTextOption,
@@ -358,7 +362,7 @@ def get_valid_files(self, files_with_prefix: Optional[List[str]]) -> Set[str]:
 
 
 class DataFileLatestGroup(DataFileGroup):
-    regex: Pattern
+    regex: re.Pattern
 
     def get_valid_files(self, files_with_prefix: Optional[List[str]]) -> Set[str]:
         if files_with_prefix is not None:

lean/models/market_hours_database.py

@@ -14,7 +14,7 @@
 from datetime import datetime
 from typing import List, Dict, Any
 
-from lean.models.pydantic import WrappedBaseModel, validator
+from lean.models.pydantic import WrappedBaseModel, field_validator
 
 class MarketHoursSegment(WrappedBaseModel):
     start: str
@@ -36,7 +36,8 @@ class MarketHoursDatabaseEntry(WrappedBaseModel):
     earlyCloses: Dict[str, str] = {}
     lateOpens: Dict[str, str] = {}
 
-    @validator("holidays", pre=True)
+    @field_validator("holidays", mode="before")
+    @classmethod
     def parse_holidays(cls, value: Any) -> Any:
         if isinstance(value, list):
             return [datetime.strptime(x, "%m/%d/%Y") for x in value]

lean/models/pydantic.py

@@ -11,26 +11,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from pydantic import __version__ as pydantic_version
-if pydantic_version.startswith("1."):
-    # We keep all this imports here, even if not used like validator, so other files can import them through this file
-    # to avoid having to check the pydantic version in every file.
-    # All imports should be done through this file to avoid pydantic version related errors.
-    from pydantic import BaseModel, ValidationError, Field, validator
-else:
-    from pydantic.v1 import BaseModel, ValidationError, Field, validator
+from pathlib import Path
+from typing import Annotated
+from pydantic import BaseModel, BeforeValidator, ConfigDict, ValidationError, Field, field_validator
+
+# Path field that accepts str | Path. Converts in Python before pydantic-core runs,
+# avoiding issues when pathlib is patched at runtime (e.g. pyfakefs).
+SafePath = Annotated[Path, BeforeValidator(lambda v: v if isinstance(v, Path) else Path(v))]
+
 
 class WrappedBaseModel(BaseModel):
     """A version of Pydantic's BaseModel which makes the input data accessible in case of a validation error."""
 
-    def __init__(self, *args, **kwargs) -> None:
-        """Creates a new WrappedBaseModel instance.
-
-        :param args: args to pass on to the BaseModel constructor
-        :param kwargs: kwargs to pass on to the BaseModel constructor
-        """
-        try:
-            super().__init__(*args, **kwargs)
-        except ValidationError as error:
-            error.input_value = kwargs
-            raise error
+    # Ensures backward compatibility: automatically converts numeric inputs to strings for string fields
+    model_config = ConfigDict(coerce_numbers_to_str=True)

lean/models/utils.py

@@ -12,9 +12,8 @@
 # limitations under the License.
 
 from enum import Enum
-from pathlib import Path
 
-from lean.models.pydantic import WrappedBaseModel
+from lean.models.pydantic import WrappedBaseModel, SafePath
 
 class DebuggingMethod(Enum):
     """The debugging methods supported by the CLI."""
@@ -47,4 +46,4 @@ class CSharpLibrary(WrappedBaseModel):
 class LeanLibraryReference(WrappedBaseModel):
     """The information of a library reference in a project's config.json file"""
     name: str
-    path: Path
+    path: SafePath

requirements.txt

@@ -1,12 +1,13 @@
 # This file contains development dependencies
 # Production dependencies are stored in setup.py
 
+setuptools==69.5.1
 -e .
 
 wheel
 pytest>=7.1.2,<8
 pyfakefs>=5.4.1,<6
 responses~=0.21
 lxml-stubs==0.4.0
-# Match pandas version to use same as Lean. Except that 2.1.* is only supported on Python 3.9+.
-pandas==2.2.3;python_version>='3.9'
+# Match pandas version used by LEAN. No prebuilt wheel for Python 3.14+, quantconnect-stubs will install a compatible version.
+pandas==2.2.3;python_version>='3.9' and python_version<'3.14'

setup.py

@@ -51,8 +51,9 @@ def get_stubs_version_range() -> str:
     "json5>=0.9.8",
     "docker>=6.0.0",
     "rich>=9.10.0",
-    "pydantic>=1.8.2",
+    "pydantic>=2.0.0",
     "python-dateutil>=2.8.2",
+    "pytz",
     "lxml>=4.9.0",
     "joblib>=1.1.0",
     "setuptools",
@@ -77,20 +78,19 @@ def get_stubs_version_range() -> str:
         "console_scripts": ["lean=lean.main:main"]
     },
     install_requires=install_requires,
-    python_requires=">= 3.7",
+    python_requires=">= 3.9",
     classifiers=[
         "Development Status :: 5 - Production/Stable",
         "Intended Audience :: Developers",
         "Intended Audience :: Financial and Insurance Industry",
         "License :: OSI Approved :: Apache Software License",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.7",
-        "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
-        "Programming Language :: Python :: 3.13"
+        "Programming Language :: Python :: 3.13",
+        "Programming Language :: Python :: 3.14"
     ],
     project_urls={
         "Documentation": "https://www.lean.io/docs/v2/lean-cli/key-concepts/getting-started",