Revert "[3.15] gh-156545: Fix flamegraph export RecursionError on dee…

…ply recursive programs (GH-156546) (#158851)" This reverts commit 0ac7217.
pablogsal · Oct 5, 2026 · Oct 5, 2026 · Oct 5, 2026 · Oct 5, 2026 · Oct 5, 2026
commit ebe784edaae37ea849975061f8712227b7e8ffb9
@@ -68,10 +68,6 @@ def export(self, filename):
         return True
 
 
-# Bounded by the unwinder's maximum captured stack depth (MAX_FRAMES).
-_FLAMEGRAPH_RECURSION_MARGIN = 2000
-
-
 class FlamegraphCollector(StackTraceCollector):
     def __init__(self, *args, **kwargs):
         super().__init__(*args, **kwargs)
@@ -170,41 +166,34 @@ def set_mode(self, mode):
         self.stats["mode"] = mode
 
     def export(self, filename):
-        # Converting the call tree recurses to the sampled stack depth.
-        old_limit = sys.getrecursionlimit()
-        sys.setrecursionlimit(old_limit + _FLAMEGRAPH_RECURSION_MARGIN)
-        try:
-            flamegraph_data = self._convert_to_flamegraph_format()
-
-            # Debug output with string table statistics
-            num_functions = len(flamegraph_data.get("children", []))
-            total_time = flamegraph_data.get("value", 0)
-            string_count = len(self._string_table)
-            s1 = "" if num_functions == 1 else "s"
-            s2 = "" if total_time == 1 else "s"
-            s3 = "" if string_count == 1 else "s"
+        flamegraph_data = self._convert_to_flamegraph_format()
+
+        # Debug output with string table statistics
+        num_functions = len(flamegraph_data.get("children", []))
+        total_time = flamegraph_data.get("value", 0)
+        string_count = len(self._string_table)
+        s1 = "" if num_functions == 1 else "s"
+        s2 = "" if total_time == 1 else "s"
+        s3 = "" if string_count == 1 else "s"
+        print(
+            f"Flamegraph data: {num_functions} root function{s1}, "
+            f"{total_time} total sample{s2}, "
+            f"{string_count} unique string{s3}"
+        )
+
+        if num_functions == 0:
             print(
-                f"Flamegraph data: {num_functions} root function{s1}, "
-                f"{total_time} total sample{s2}, "
-                f"{string_count} unique string{s3}"
+                "Warning: No functions found in profiling data. Check if sampling captured any data."
             )
+            return False
 
-            if num_functions == 0:
-                print(
-                    "Warning: No functions found in profiling data. "
-                    "Check if sampling captured any data."
-                )
-                return False
-
-            html_content = self._create_flamegraph_html(flamegraph_data)
+        html_content = self._create_flamegraph_html(flamegraph_data)
 
-            with open(filename, "w", encoding="utf-8") as f:
-                f.write(html_content)
+        with open(filename, "w", encoding="utf-8") as f:
+            f.write(html_content)
 
-            print(f"Flamegraph saved to: {filename}")
-            return True
-        finally:
-            sys.setrecursionlimit(old_limit)
+        print(f"Flamegraph saved to: {filename}")
+        return True
 
     @staticmethod
     @functools.lru_cache(maxsize=None)

@@ -4,11 +4,10 @@
 import marshal
 import opcode
 import os
-import sys
 import tempfile
 import unittest
 
-from test.support import is_emscripten, set_recursion_limit
+from test.support import is_emscripten
 
 try:
     import _remote_debugging  # noqa: F401
@@ -611,38 +610,6 @@ def test_flamegraph_collector_empty_export_fails(self):
         self.assertFalse(export_ok)
         self.assertEqual(os.path.getsize(flamegraph_out.name), 0)
 
-    def test_flamegraph_deep_stack_export(self):
-        flamegraph_out = tempfile.NamedTemporaryFile(
-            suffix=".html", delete=False
-        )
-        self.addCleanup(close_and_unlink, flamegraph_out)
-
-        collector = FlamegraphCollector(1000)
-        # Deeper than the default recursion limit.
-        frames = [MockFrameInfo("f.py", i + 1, f"f{i}") for i in range(1536)]
-        collector.collect(
-            [MockInterpreterInfo(0, [MockThreadInfo(1, frames)])])
-
-        with set_recursion_limit(1000), captured_stdout(), captured_stderr():
-            export_ok = collector.export(flamegraph_out.name)
-            self.assertEqual(sys.getrecursionlimit(), 1000)
-
-        self.assertTrue(export_ok)
-        self.assertGreater(os.path.getsize(flamegraph_out.name), 0)
-
-    def test_flamegraph_export_restores_recursion_limit(self):
-        collector = FlamegraphCollector(1000)
-        frame = MockFrameInfo("f.py", 1, "f")
-        with set_recursion_limit(500), captured_stdout(), captured_stderr():
-            self.assertFalse(collector.export(None))
-            self.assertEqual(sys.getrecursionlimit(), 500)
-            collector.collect([
-                MockInterpreterInfo(0, [MockThreadInfo(1, [
-                    frame, MockFrameInfo("f.py", 2, "caller")])])])
-            with self.assertRaises(TypeError):
-                collector.export(None)
-            self.assertEqual(sys.getrecursionlimit(), 500)
-
     def test_gecko_collector_basic(self):
         """Test basic GeckoCollector functionality."""
         collector = GeckoCollector(1000)

diff --git a/Misc/NEWS.d/next/Library/2026-08-29-11-37-40.gh-issue-156545.fLaMe1.rst b/Misc/NEWS.d/next/Library/2026-08-29-11-37-40.gh-issue-156545.fLaMe1.rst