func.fillet / func.chamfer segfault instead of raising when the operation fails #2114

cadquery.func.fillet and cadquery.func.chamfer call builder.Build() and then builder.Shape(). If the build failed, BRepBuilderAPI_MakeShape::Shape() calls Build() again, and the second build of BRepFilletAPI_MakeFillet / MakeChamfer segfaults inside OCCT. So a fillet that should raise StdFail_NotDone kills the process. The method Solid.fillet builds only once and raises correctly.

To Reproduce

from cadquery.func import box, fillet

b = box(10, 10, 10)
fillet(b, b.edges(), 5)  # segfault; b.fillet(5, b.Edges()) raises StdFail_NotDone

chamfer(b, b.edges(), 5) crashes the same way.

Backtrace

Python (python -X faulthandler; this is the complete stack):

Fatal Python error: Segmentation fault

Current thread 0x00007ba959a21780 [python] (most recent call first):
  File ".../site-packages/cadquery/occ_impl/shapes.py", line 7225 in fillet
  File "mre_fillet_crash.py", line 4 in <module>

Native (C stack printed by faulthandler; no gdb/lldb available; Python interpreter frames omitted, symbols demangled):

libTKFillet.so.8.0.1   ChFi3d_Builder::UpdateTolesp()+0x28
libTKFillet.so.8.0.1   ChFi3d_Builder::Compute()+0x1e
libTKFillet.so.8.0.1   BRepFilletAPI_MakeFillet::Build(Message_ProgressRange const&)+0x1a
libTKTopAlgo.so.8.0.1  BRepBuilderAPI_MakeShape::Shape()+0x3b
OCP.cpython-314-x86_64-linux-gnu.so +0x141afcb

Suggested fix

Check the result before anything else touches the builder:

     builder.Build()
 
+    if not builder.IsDone():
+        raise ValueError("Fillet failed")
+
     _update_history(history, name, [s, edges], builder)

and the same in chamfer (the same kind of guard as #2106 adds for n_sided). With this change the example raises ValueError, and tests/test_free_functions.py passes (apart from two font tests that fail without Arial installed). I can open a PR if that helps.

Environment

OS:

Ubuntu 26.04.1 LTS, x86_64

Was CadQuery installed using Conda?: No. Fresh virtual environment created with uv (uv venv --python 3.14, uv-managed CPython 3.14.8), then uv pip install of a git checkout of master (5f5bc62), which pulls the cadquery-ocp 8.0.1.1 wheel from PyPI. The same crash occurs with the release: cadquery 2.8.0 and cadquery-ocp 7.9.3.1.1 from PyPI.

Output of uv pip list from the active environment:

Package            Version
------------------ -----------
aiohappyeyeballs   2.7.1
aiohttp            3.14.5
aiosignal          1.4.0
attrs              26.1.0
cadquery           2.9.0.dev0
cadquery-ocp       8.0.1.1.0
cadquery-ocp-proxy 8.0.1.1.0
casadi             3.8.1
contourpy          1.4.0
cycler             0.12.1
ezdxf              1.4.5
fonttools          4.67.0
frozenlist         1.8.0
idna               3.20
iniconfig          2.3.1
kiwisolver         1.5.1
llvmlite           0.50.0
matplotlib         3.11.2
more-itertools     11.2.1
msgpack            1.2.3
multidict          7.1.0
multimethod        2.1
nlopt              2.11.0
numba              0.68.0
numpy              2.5.4
packaging          26.3
pillow             13.0.0
pluggy             1.7.0
propcache          0.5.4
pygments           2.21.0
pyparsing          3.3.3
pytest             9.1.1
python-dateutil    2.9.0.post0
pyyaml             6.0.3
runtype            0.5.3
scipy              1.18.1
six                1.17.0
trame              4.0.0
trame-client       4.1.4
trame-common       1.2.9
trame-components   2.5.0
trame-server       4.1.0
trame-vtk          2.11.17
trame-vuetify      3.3.0
typing-extensions  4.16.0
vtk                9.6.2
wslink             2.6.0
yarl               1.25.1

Using:

Python interpreter