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Preserve NameError/AttributeError suggestions in traceback formatting #15263

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Preserve NameError/AttributeError suggestions in traceback formatting #15263

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7952602
Preserve NameError suggestions in traceback formatting
shincho-1000 Jun 15, 2026
894d7f8
Merge branch 'main' into fix-nameerror-suggestions
Carreau Jun 26, 2026
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31 changes: 25 additions & 6 deletions IPython/core/ultratb.py
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Original file line number Diff line number Diff line change
Expand Up @@ -210,7 +210,7 @@ def structured_traceback(
)
out_list.extend(self._format_list(elist))
# The exception info should be a single entry in the list.
lines = "".join(self._format_exception_only(etype, evalue))
lines = "".join(self._format_exception_only(etype, evalue, etb))
out_list.append(lines)

# Find chained exceptions if we have a traceback (not for exception-only mode)
Expand Down Expand Up @@ -288,7 +288,7 @@ def _format_list(self, extracted_list: list[Any]) -> list[str]:
return output_list

def _format_exception_only(
self, etype: type[BaseException], value: BaseException | None
self, etype: type[BaseException], value: BaseException | None, etb: TracebackType | None
) -> list[str]:
"""Format the exception part of a traceback.

Expand Down Expand Up @@ -372,7 +372,14 @@ def _format_exception_only(
)
s = value.msg
else:
s = self._some_str(value)
if isinstance(etb, TracebackType):
last_line = traceback.format_exception(etype, value, etb)[-1]
if ": " in last_line:
s = last_line.split(": ", 1)[1].rstrip()
else:
s = last_line.rstrip()
else:
s = self._some_str(value)
if s:
output_list.append(
theme_table[self._theme_name].format(
Expand Down Expand Up @@ -748,10 +755,22 @@ def prepare_header(self, etype: str, long_version: bool = False) -> str:

return head

def format_exception(self, etype, evalue):
def format_exception(self, etype, evalue, etb=None):
# Get (safely) a string form of the exception info
try:
etype_str, evalue_str = map(str, (etype, evalue))
etype_str = str(etype)

if isinstance(etb, TracebackType):
last_line = traceback.format_exception(
etype, evalue, etb
)[-1]

if ": " in last_line:
evalue_str = last_line.split(": ", 1)[1].rstrip()
else:
evalue_str = last_line.rstrip()
else:
evalue_str = str(evalue)
except:
# User exception is improperly defined.
etype, evalue = str, sys.exc_info()[:2]
Expand Down Expand Up @@ -840,7 +859,7 @@ def format_exception_as_a_whole(
)
)

formatted_exception = self.format_exception(etype, evalue)
formatted_exception = self.format_exception(etype, evalue, etb)
if records:
frame_info = records[-1]
ipinst = get_ipython()
Expand Down
19 changes: 19 additions & 0 deletions tests/test_ultratb.py
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Original file line number Diff line number Diff line change
Expand Up @@ -465,6 +465,25 @@ def test_jsondecodeerror_message(self):
ip.run_cell(cell)
ip.run_cell("%xmode context")

class NameErrorSuggestionTest(unittest.TestCase):
def test_verbose_nameerror_suggestion(self):
ip.run_cell("%xmode Verbose")
with tt.AssertPrints(
["NameError", "Did you mean", "print"],
suppress=False,
):
ip.run_cell("printn('hello')")

def test_plain_nameerror_suggestion(self):
ip.run_cell("%xmode Plain")
try:
with tt.AssertPrints(
["NameError", "Did you mean", "print"],
suppress=False,
):
ip.run_cell("printn('hello')")
finally:
ip.run_cell("%xmode Verbose")

# ----------------------------------------------------------------------------

Expand Down
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