[Feature] Pretty Pydantic `ValidationError` exceptions (#6130)

* fix validator in fmp IndexHistorical model

* make ValidationError pretty

* modify arg error

* linting fmp IndexHistorical

* black

* remove unused code

2 files changed, 32 insertions, 7 deletions

diff --git a/openbb_platform/core/openbb_core/app/static/utils/decorators.py b/openbb_platform/core/openbb_core/app/static/utils/decorators.py
index 3c20559d475..7a9af5ead87 100644
--- a/openbb_platform/core/openbb_core/app/static/utils/decorators.py
+++ b/openbb_platform/core/openbb_core/app/static/utils/decorators.py
@@ -5,7 +5,7 @@ from typing import Any, Callable, Optional, TypeVar, overload
 
 from openbb_core.app.model.abstract.error import OpenBBError
 from openbb_core.env import Env
-from pydantic import validate_call
+from pydantic import ValidationError, validate_call
 from typing_extensions import ParamSpec
 
 P = ParamSpec("P")
@@ -44,14 +44,36 @@ def exception_handler(func: Callable[P, R]) -> Callable[P, R]:
     """Handle exceptions, attempting to focus on the last call from the traceback."""
 
     @wraps(func)
-    def wrapper(*args, **kwargs):
+    def wrapper(*f_args, **f_kwargs):
         try:
-            return func(*args, **kwargs)
-        except Exception as e:
+            return func(*f_args, **f_kwargs)
+        except (ValidationError, Exception) as e:
             if Env().DEBUG_MODE:
                 raise
+            if isinstance(e, ValidationError):
+                error_list = []
+
+                validation_error = f"{e.error_count()} validations errors in {e.title}"
+                for error in e.errors():
+                    arg_error = f"Arg {error['loc'][0]} ->\n"
+                    error_details = (
+                        f"  {error['msg']} "
+                        f"[validation_error_type={error['type']}, "
+                        f"input_type={type(error['input']).__name__}, "
+                        f"input_value={error['input']}]\n"
+                    )
+                    error_info = f"    For further information visit {error['url']}\n"
+                    error_list.append(arg_error + error_details + error_info)
+
+                error_list.insert(0, validation_error)
+                error_str = "\n".join(error_list)
+                raise OpenBBError(
+                    f"\nType -> ValidationError \n\nDetails -> {error_str}"
+                ) from None
+
+            # If the error is not a ValidationError, then it is a generic exception
             raise OpenBBError(
-                f"\nType -> {e.__class__.__name__}\n\nDetail -> {str(e)}"
+                f"\nType -> {e.original.original.__class__.__name__}\n\nDetail -> {str(e)}"
             ) from None
 
     return wrapper
diff --git a/openbb_platform/providers/fmp/openbb_fmp/models/index_historical.py b/openbb_platform/providers/fmp/openbb_fmp/models/index_historical.py
index 8ebf3db2f38..087f6fa15f7 100644
--- a/openbb_platform/providers/fmp/openbb_fmp/models/index_historical.py
+++ b/openbb_platform/providers/fmp/openbb_fmp/models/index_historical.py
@@ -30,7 +30,7 @@ class FMPIndexHistoricalQueryParams(IndexHistoricalQueryParams):
         Field(default="1day", description="Data granularity.")
     )
 
-    @field_validator("interval")
+    @field_validator("interval", mode="before", check_fields=True)
     @classmethod
     def map_interval(cls, v):
         """Map the interval from standard to the FMP format."""
@@ -104,9 +104,12 @@ class FMPIndexHistoricalFetcher(
 
         return await get_data_many(url, "historical", **kwargs)
 
+    # pylint: disable=unused-argument
     @staticmethod
     def transform_data(
-        query: FMPIndexHistoricalQueryParams, data: List[Dict], **kwargs: Any
+        query: FMPIndexHistoricalQueryParams,
+        data: List[Dict],
+        **kwargs: Any,
     ) -> List[FMPIndexHistoricalData]:
         """Return the transformed data."""
         return [