drop(grouping): Drop hierarchical_grouping feature

This partially reverts #23861

A lot more code needs to be removed but this is the minimal removal which passes all tests.

src/sentry/grouping/strategies/configurations.py

@@ -53,10 +53,6 @@
         # newstyle: turns on falling back to exception values when there
         # is no stacktrace.
         "with_exception_value_fallback": False,
-        # Whether the strategy should produce special variants that are
-        # considered for hierarchical grouping (see HIERARCHICAL_VARIANTS
-        # constant)
-        "hierarchical_grouping": False,
         # Stacktrace is produced in the context of this exception
         "exception_data": None,
         # Whether to discard filenames of native events for grouping if
@@ -173,7 +169,6 @@ def register_strategy_config(id: str, **kwargs) -> type[StrategyConfiguration]:
           no longer result in different issues.
     """,
     initial_context={
-        "hierarchical_grouping": True,
         "discard_native_filename": True,
         "use_package_fallback": True,
         "native_fuzzing": True,

src/sentry/grouping/strategies/newstyle.py

@@ -14,7 +14,6 @@
     call_with_variants,
     strategy,
 )
-from sentry.grouping.strategies.hierarchical import get_stacktrace_hierarchy
 from sentry.grouping.strategies.message import normalize_message_for_grouping
 from sentry.grouping.strategies.utils import has_url_origin, remove_non_stacktrace_variants
 from sentry.grouping.utils import hash_from_values
@@ -465,20 +464,14 @@ def stacktrace(
 ) -> ReturnedVariants:
     assert context["variant"] is None
 
-    if context["hierarchical_grouping"]:
-        with context:
-            context["variant"] = "system"
-            return _single_stacktrace_variant(interface, event=event, context=context, meta=meta)
-
-    else:
-        return call_with_variants(
-            _single_stacktrace_variant,
-            ["!system", "app"],
-            interface,
-            event=event,
-            context=context,
-            meta=meta,
-        )
+    return call_with_variants(
+        _single_stacktrace_variant,
+        ["!system", "app"],
+        interface,
+        event=event,
+        context=context,
+        meta=meta,
+    )
 
 
 def _single_stacktrace_variant(
@@ -496,7 +489,7 @@ def _single_stacktrace_variant(
             context["is_recursion"] = is_recursion_v1(frame, prev_frame)
             frame_component = context.get_single_grouping_component(frame, event=event, **meta)
 
-        if not context["hierarchical_grouping"] and variant == "app" and not frame.in_app:
+        if variant == "app" and not frame.in_app:
             frame_component.update(contributes=False, hint="non app frame")
         values.append(frame_component)
         frames_for_filtering.append(frame.get_raw_data())
@@ -526,17 +519,7 @@ def _single_stacktrace_variant(
 
     inverted_hierarchy = bool(inverted_hierarchy)
 
-    if not context["hierarchical_grouping"]:
-        return {variant: main_variant}
-
-    all_variants = get_stacktrace_hierarchy(
-        main_variant, values, frames_for_filtering, inverted_hierarchy
-    )
-
-    # done for backwards compat to find old groups
-    all_variants["system"] = main_variant
-
-    return all_variants
+    return {variant: main_variant}
 
 
 @stacktrace.variant_processor