Add DeprecationError exception and migrate raise DeprecationWarning usages

ax/adapter/pairwise.py

@@ -9,12 +9,13 @@
 from typing import Any
 
 from ax.adapter.torch import TorchAdapter
+from ax.exceptions.core import DeprecationError
 
 
 # PairwiseAdapter was deprecated in Ax 1.1.0, so it should be reaped in Ax
 # 1.2.0+
 class PairwiseAdapter(TorchAdapter):
     def __init__(self, **kwargs: Any) -> None:
-        raise DeprecationWarning(
+        raise DeprecationError(
             "PairwiseAdapter is deprecated. Use TorchAdapter instead."
         )

ax/core/batch_trial.py

@@ -26,7 +26,12 @@
     TEvaluationOutcome,
     validate_evaluation_outcome,
 )
-from ax.exceptions.core import AxError, UnsupportedError, UserInputError
+from ax.exceptions.core import (
+    AxError,
+    DeprecationError,
+    UnsupportedError,
+    UserInputError,
+)
 from ax.utils.common.base import SortableBase
 from ax.utils.common.docutils import copy_doc
 from ax.utils.common.equality import datetime_equals, equality_typechecker
@@ -183,7 +188,7 @@ def arm_weights(self) -> MutableMapping[Arm, float]:
 
     @property
     def _status_quo_weight_override(self) -> None:
-        raise DeprecationWarning(
+        raise DeprecationError(
             "Status quo weight override is no longer supported. Please "
             "contact the Ax developers for help adjusting your application."
         )

ax/exceptions/core.py

@@ -41,6 +41,22 @@ class UnsupportedError(AxError):
     """
 
 
+class DeprecationError(AxError):
+    """Raised when deprecated functionality is accessed as a hard break.
+
+    Use this for deprecations that have reached the point of removal, where
+    accessing the deprecated API (e.g. reading a removed property) should fail
+    immediately with an actionable message rather than silently returning a
+    wrong value. Prefer this over ``raise DeprecationWarning(...)``:
+    ``DeprecationWarning`` is a warning *category*, not an exception type, so
+    raising it is semantically incorrect and is not suppressible via
+    ``warnings.simplefilter("ignore", DeprecationWarning)``.
+
+    For *soft* deprecations that should still work (just with a notice), use
+    ``warnings.warn(..., DeprecationWarning)`` instead of this error.
+    """
+
+
 class UnsupportedPlotError(AxError):
     """Raised when plotting functionality is not supported for the
     given configurations.

ax/service/utils/scheduler_options.py

@@ -8,9 +8,11 @@
 # Scheduler was deprecated in Ax 1.1.0, so it should be removed in Ax
 # Ax 1.2.0+.
 
+from ax.exceptions.core import DeprecationError
+
 
 class SchedulerOptions:
-    raise DeprecationWarning(
+    raise DeprecationError(
         "Scheduler is deprecated following renaming of the Scheduler to "
         "Orchestrator. Please use Orchestrator and OrchestratorOptions instead; "
         "import with: `from ax.orchestration.orchestrator import Orchestrator, "