fix: restore the trimmed execution trace

marimo/_messaging/tracebacks.py

@@ -49,10 +49,8 @@ def write_traceback(traceback: str) -> None:
         # In run mode, only forward to the frontend if show_tracebacks is on.
         if in_run_mode and not _show_tracebacks_enabled():
             return
-        # Strip marimo's internal executor.py frame and highlight for the UI
-        trimmed = _trim_traceback(traceback)
         sys.stderr._write_with_mimetype(
-            _highlight_traceback(trimmed),
+            _highlight_traceback(traceback),
             mimetype="application/vnd.marimo+traceback",
         )
     else:
@@ -64,16 +62,15 @@ def write_traceback(traceback: str) -> None:
             if in_run_mode and not _show_tracebacks_enabled():
                 sys.stderr.write(traceback)
                 return
-            trimmed = _trim_traceback(traceback)
             broadcast_notification(
                 CellNotification(
                     cell_id=ctx.cell_id,
                     console=CellOutput(
                         channel=CellChannel.STDERR,
                         mimetype="application/vnd.marimo+traceback",
-                        data=trimmed
+                        data=traceback
                         if code_mode
-                        else _highlight_traceback(trimmed),
+                        else _highlight_traceback(traceback),
                     ),
                 ),
                 ctx.stream,
@@ -83,27 +80,5 @@ def write_traceback(traceback: str) -> None:
             sys.stderr.write(traceback)
 
 
-def _trim_traceback(traceback: str) -> str:
-    """
-    Skip first DefaultExecutor.execute_cell traceback item which all traces start with.
-    """
-
-    lines = traceback.split("\n")
-    if (
-        len(lines) > 2
-        and lines[0] == "Traceback (most recent call last):"
-        and (
-            '/marimo/_runtime/executor.py", line ' in lines[1]
-            or '\\marimo\\_runtime\\executor.py", line ' in lines[1]
-        )
-        and lines[1].endswith(", in execute_cell")
-    ):
-        for i in range(2, len(lines)):
-            if lines[i].startswith("  File "):
-                return "\n".join(lines[:1] + lines[i:])
-
-    return traceback
-
-
 def is_code_highlighting(value: str) -> bool:
     return 'class="codehilite"' in value

marimo/_runtime/executor/executor.py

@@ -40,8 +40,10 @@ def execute_cell(self, cell: CellImpl, glbls: dict[str, Any]) -> Any:
             exec(cell.body, glbls)
             return eval(cell.last_expr, glbls)
         except BaseException as e:
-            # Raising from BaseException folds in the stack trace prior
-            # to execution; the Runner classifies via ``__cause__``.
+            # Strip our own frame so user-facing tracebacks start at user
+            # code. Runners classify via ``__cause__``.
+            if e.__traceback__ is not None:
+                e.__traceback__ = e.__traceback__.tb_next
             raise MarimoRuntimeException from e
 
     async def execute_cell_async(
@@ -59,4 +61,6 @@ async def execute_cell_async(
                 return await eval(cell.last_expr, glbls)
             return eval(cell.last_expr, glbls)
         except BaseException as e:
+            if e.__traceback__ is not None:
+                e.__traceback__ = e.__traceback__.tb_next
             raise MarimoRuntimeException from e

marimo/_runtime/runner/hooks_post_execution.py

@@ -35,7 +35,6 @@
 )
 from marimo._messaging.tracebacks import (
     _highlight_traceback,
-    _trim_traceback,
     write_traceback,
 )
 from marimo._messaging.variables import create_variable_value
@@ -426,9 +425,7 @@ def _broadcast_outputs(
             and run_result.exception.__traceback__
         ):
             tb_lines = tb.format_exception(run_result.exception)
-            formatted_traceback = _highlight_traceback(
-                _trim_traceback("".join(tb_lines))
-            )
+            formatted_traceback = _highlight_traceback("".join(tb_lines))
 
         CellNotificationUtils.broadcast_error(
             data=[

tests/_messaging/test_tracebacks.py

@@ -6,7 +6,6 @@
 from marimo._messaging.context import HTTP_REQUEST_CTX, is_code_mode_request
 from marimo._messaging.tracebacks import (
     _highlight_traceback,
-    _trim_traceback,
     is_code_highlighting,
     write_traceback,
 )
@@ -221,11 +220,3 @@ def test_empty_url(self) -> None:
             assert is_code_mode_request() is False
         finally:
             HTTP_REQUEST_CTX.reset(token)
-
-    def test_trim(self) -> None:
-        prefix = "Traceback (most recent call last):\n"
-        head = '  File ".../marimo/_runtime/executor.py", line 139, in execute_cell\n    return eval(cell.last_expr, glbls)\n           ^^^^^^^^^^^^^^^^^^^^^^^^^^^\n'
-        rest = (
-            '  File ".../__marimo__cell_Hbol_.py", line 2, in <module>\n...\n'
-        )
-        assert _trim_traceback(f"{prefix}{head}{rest}") == f"{prefix}{rest}"

tests/_runtime/test_executor_evaluator.py

@@ -15,6 +15,8 @@
 import asyncio
 from typing import Any
 
+import pytest
+
 from marimo._runtime.exceptions import MarimoRuntimeException
 from marimo._runtime.executor import (
     DefaultExecutor,
@@ -203,6 +205,53 @@ def is_coroutine(self) -> bool:
     assert isinstance(a.last_run_result.exception, MarimoRuntimeException)
 
 
+def _cause_traceback_filenames(exc: BaseException) -> list[str]:
+    cause = exc.__cause__
+    assert cause is not None
+    tb = cause.__traceback__
+    files: list[str] = []
+    while tb is not None:
+        files.append(tb.tb_frame.f_code.co_filename)
+        tb = tb.tb_next
+    return files
+
+
+def test_default_executor_strips_own_frame_from_cause_sync() -> None:
+    """``DefaultExecutor.execute_cell`` must not leave its own frame on
+    the cause's ``__traceback__`` — user-facing tracebacks should begin
+    at user code (the compiled ``<test>`` source)."""
+
+    class _FakeCell:
+        cell_id = "0"
+        body = compile("raise ValueError('user bomb')", "<test>", "exec")
+        last_expr = compile("None", "<test>", "eval")
+
+    with pytest.raises(MarimoRuntimeException) as exc_info:
+        DefaultExecutor().execute_cell(_FakeCell(), {})  # type: ignore[arg-type]
+
+    files = _cause_traceback_filenames(exc_info.value)
+    assert files, "cause traceback unexpectedly empty"
+    assert not any("executor/executor.py" in f for f in files), files
+    assert files[0] == "<test>"
+
+
+async def test_default_executor_strips_own_frame_from_cause_async() -> None:
+    """Same as the sync variant, for ``execute_cell_async``."""
+
+    class _FakeCell:
+        cell_id = "0"
+        body = compile("raise ValueError('user bomb')", "<test>", "exec")
+        last_expr = compile("None", "<test>", "eval")
+
+    with pytest.raises(MarimoRuntimeException) as exc_info:
+        await DefaultExecutor().execute_cell_async(_FakeCell(), {})  # type: ignore[arg-type]
+
+    files = _cause_traceback_filenames(exc_info.value)
+    assert files, "cause traceback unexpectedly empty"
+    assert not any("executor/executor.py" in f for f in files), files
+    assert files[0] == "<test>"
+
+
 async def test_teardown_runs_for_completed_setups_when_later_setup_raises() -> (
     None
 ):

tests/_server/test_scratchpad_integration.py

@@ -671,7 +671,7 @@ def test_ctx_create_cell_multiply_defined(session: _Session) -> None:
     assert lines == snapshot(
         [
             "event: stderr",
-            'data: {"data": "Traceback (most recent call last):\\n  File \\"<marimo>/marimo/_runtime/executor.py\\", line N, in execute_cell_async\\n    await eval(cell.body, glbls)\\n  File \\"<tmp>\\", line 2, in <module>\\n    async with cm.get_context() as ctx:\\n  File \\"<marimo>/marimo/_code_mode/_context.py\\", line N, in __aexit__\\n    self._dry_run_compile(ops)\\n  File \\"<marimo>/marimo/_code_mode/_context.py\\", line N, in _dry_run_compile\\n    raise RuntimeError(\\nRuntimeError: Multiply-defined names:\\n  - \'x\' is already defined in cell \'cell_a\' (cell_a)\\n\\nTo skip validation, use: async with cm.get_context(skip_validation=True) as ctx\\n"}',
+            'data: {"data": "Traceback (most recent call last):\\n  File \\"<tmp>\\", line 2, in <module>\\n    async with cm.get_context() as ctx:\\n  File \\"<marimo>/marimo/_code_mode/_context.py\\", line N, in __aexit__\\n    self._dry_run_compile(ops)\\n  File \\"<marimo>/marimo/_code_mode/_context.py\\", line N, in _dry_run_compile\\n    raise RuntimeError(\\nRuntimeError: Multiply-defined names:\\n  - \'x\' is already defined in cell \'cell_a\' (cell_a)\\n\\nTo skip validation, use: async with cm.get_context(skip_validation=True) as ctx\\n"}',
             "",
             "event: done",
             'data: {"success": false, "output": {"mimetype": "text/plain", "data": ""}}',