ref(tracing): Simplify backwards-compat code

With this change, we aim to simplify the backwards-compatibility code
for POTel tracing.

We do this as follows:
  - Remove `start_*` functions from `tracing`
  - Remove unused parameters from `tracing.POTelSpan.__init__`
  - Completely remove `start_inactive_span`, since inactive spans can
    be created by setting `active=False` when constructing a
    `POTelSpan`.
  - Handle backwards-compatibility in top-level API by stripping any
    invalid `kwargs` before calling the `POTelSpan` constructor.

sentry_sdk/api.py

@@ -78,13 +78,15 @@ def overload(x):
     "set_tags",
     "set_user",
     "start_span",
-    "start_inactive_span",
     "start_transaction",
     "trace",
     "monitor",
 ]
 
 
+_potel_span_init_kwargs = None
+
+
 def scopemethod(f):
     # type: (F) -> F
     f.__doc__ = "%s\n\n%s" % (
@@ -339,14 +341,16 @@ def start_span(
     **kwargs,  # type: Any
 ):
     # type: (...) -> POTelSpan
-    return tracing.start_span(**kwargs)
+    global _potel_span_init_kwargs
 
+    if _potel_span_init_kwargs is None:
+        _potel_span_init_kwargs = inspect.signature(tracing.POTelSpan).parameters.keys()
 
-def start_inactive_span(
-    **kwargs,  # type: Any
-):
-    # type: (...) -> POTelSpan
-    return tracing.start_inactive_span(**kwargs)
+    filtered_kwargs = {
+        kwarg: kwargs[kwarg] for kwarg in _potel_span_init_kwargs if kwarg in kwargs
+    }
+
+    return tracing.POTelSpan(**filtered_kwargs)
 
 
 def start_transaction(
@@ -388,7 +392,7 @@ def start_transaction(
         constructor. See :py:class:`sentry_sdk.tracing.Transaction` for
         available arguments.
     """
-    return tracing.start_transaction(transaction, custom_sampling_context, **kwargs)
+    return start_span(**kwargs)
 
 
 def set_measurement(name, value, unit=""):

sentry_sdk/tracing.py

@@ -1249,18 +1249,10 @@ class POTelSpan:
 
     def __init__(
         self,
+        *,
         active=True,  # type: bool
-        trace_id=None,  # type: Optional[str]
-        span_id=None,  # type: Optional[str]
-        parent_span_id=None,  # type: Optional[str]
-        same_process_as_parent=True,  # type: bool
-        sampled=None,  # type: Optional[bool]
         op=None,  # type: Optional[str]
         description=None,  # type: Optional[str]
-        status=None,  # type: Optional[str]
-        containing_transaction=None,  # type: Optional[Transaction]
-        start_timestamp=None,  # type: Optional[Union[datetime, float]]
-        scope=None,  # type: Optional[sentry_sdk.Scope]
         origin="manual",  # type: str
     ):
         # type: (...) -> None
@@ -1443,19 +1435,6 @@ async def my_async_function():
         return start_child_span_decorator
 
 
-def start_span(*args, **kwargs):
-    return POTelSpan(*args, active=True, **kwargs)
-
-
-def start_inactive_span(*args, **kwargs):
-    return POTelSpan(*args, active=False, **kwargs)
-
-
-def start_transaction(*args, **kwargs):
-    # XXX force_transaction?
-    return POTelSpan(*args, active=True, **kwargs)
-
-
 # Circular imports
 
 from sentry_sdk.tracing_utils import (