chirality command: UnboundLocalError

[goddard@…]

The following bug report has been submitted:
Platform:        macOS-26.2-arm64-arm-64bit
ChimeraX Version: 1.12.dev202602142240 (2026-02-14 22:40:36 UTC)
Description
Chirality command fails with this small molecule generated from a SMILES string.

Log:
UCSF ChimeraX version: 1.12.dev202602142240 (2026-02-14)  
© 2016-2026 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open
> smiles:C[C@H]([C@@H](C(=O)N1CCC[C@H]1C2=NC3=C(N2)C=C(C(=C3)F)[C@H]4CC[C@@H](N4C5=CC(=C(C(=C5)F)N6CCC(CC6)C7=CC=C(C=C7)F)F)C8=CC9=C(C=C8F)N=C(N9)[C@@H]1CCCN1C(=O)[C@H]([C@@H](C)OC)NC(=O)OC)NC(=O)OC)OC

Translated SMILES to 3D structure via NCI web service (SMILES:
C[C@H]([C@@H](C(=O)N1CCC[C@H]1C2=NC3=C(N2)C=C(C(=C3)F)[C@H]4CC[C@@H](N4C5=CC(=C(C(=C5)F)N6CCC(CC6)C7=CC=C(C=C7)F)F)C8=CC9=C(C=C8F)N=C(N9)[C@@H]1CCCN1C(=O)[C@H]([C@@H](C)OC)NC(=O)OC)NC(=O)OC)OC)  

> chirality #1

Traceback (most recent call last):  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/cmd_line/tool.py", line 322, in execute  
cmd.run(cmd_text)  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/core/commands/cli.py", line 3237, in run  
result = ci.function(session, **kw_args)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/cmd.py", line 42, in chirality_cmd  
chiralities = [chirality(atom) for atom in centers]  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/cmd.py", line 42, in <listcomp>  
chiralities = [chirality(atom) for atom in centers]  
^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/chirality.py", line 46, in chirality  
if branches_distinct(branches, visited):  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/chirality.py", line 117, in branches_distinct  
return branches_distinct(branches, visited)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/chirality.py", line 117, in branches_distinct  
return branches_distinct(branches, visited)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/chirality.py", line 117, in branches_distinct  
return branches_distinct(branches, visited)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^  
[Previous line repeated 2 more times]  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/chirality.py", line 86, in branches_distinct  
check_double = wa_info.geometry == 3 and not wa.already_double  
^^^^^^^  
UnboundLocalError: cannot access local variable 'wa_info' where it is not
associated with a value  
  
UnboundLocalError: cannot access local variable 'wa_info' where it is not
associated with a value  
  
File
"/Users/goddard/ucsf/chimerax/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-
packages/chimerax/atomic/chirality.py", line 86, in branches_distinct  
check_double = wa_info.geometry == 3 and not wa.already_double  
^^^^^^^  
  
See log for complete Python traceback.  
  




OpenGL version: 4.1 Metal - 90.5
OpenGL renderer: Apple M1 Max
OpenGL vendor: Apple

Python: 3.11.9
Locale: en_US.UTF-8
Qt version: PySide6 6.10.1, Qt 6.10.1
Qt runtime version: 6.10.1
Qt platform: cocoa
Hardware:

    Hardware Overview:

      Model Name: MacBook Pro
      Model Identifier: MacBookPro18,2
      Model Number: MK1H3LL/A
      Chip: Apple M1 Max
      Total Number of Cores: 10 (8 performance and 2 efficiency)
      Memory: 32 GB
      System Firmware Version: 13822.61.10
      OS Loader Version: 13822.61.10

Software:

    System Software Overview:

      System Version: macOS 26.2 (25C56)
      Kernel Version: Darwin 25.2.0
      Time since boot: 8 days, 22 hours, 41 minutes

Graphics/Displays:

    Apple M1 Max:

      Chipset Model: Apple M1 Max
      Type: GPU
      Bus: Built-In
      Total Number of Cores: 32
      Vendor: Apple (0x106b)
      Metal Support: Metal 4
      Displays:
        Color LCD:
          Display Type: Built-in Liquid Retina XDR Display
          Resolution: 3456 x 2234 Retina
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Automatically Adjust Brightness: No
          Connection Type: Internal


Installed Packages:
    accessible-pygments: 0.0.5
    aiohappyeyeballs: 2.6.1
    aiohttp: 3.13.1
    aiosignal: 1.4.0
    alabaster: 1.0.0
    annotated-types: 0.7.0
    anyio: 4.12.1
    appdirs: 1.4.4
    appnope: 0.1.4
    asttokens: 3.0.1
    attrs: 25.4.0
    babel: 2.18.0
    beautifulsoup4: 4.13.5
    blockdiag: 3.0.0
    blosc2: 4.0.0
    build: 1.3.0
    certifi: 2025.8.3
    cftime: 1.6.5
    charset-normalizer: 3.4.4
    ChimeraX-AddCharge: 1.5.20
    ChimeraX-AddH: 2.2.8
    ChimeraX-AlignmentAlgorithms: 2.0.2
    ChimeraX-AlignmentHdrs: 3.6.2
    ChimeraX-AlignmentMatrices: 2.1
    ChimeraX-Alignments: 3.2
    ChimeraX-AlphaFold: 1.0.1
    ChimeraX-AltlocExplorer: 1.2
    ChimeraX-AmberInfo: 1.0
    ChimeraX-Animations: 1.0
    ChimeraX-Aniso: 1.3.2
    ChimeraX-Arrays: 1.1
    ChimeraX-Atomic: 1.63.0
    ChimeraX-AtomicLibrary: 14.2.3
    ChimeraX-AtomSearch: 2.0.1
    ChimeraX-AxesPlanes: 2.4
    ChimeraX-BasicActions: 1.1.3
    ChimeraX-BILD: 1.0
    ChimeraX-BlastProtein: 3.0.0
    ChimeraX-Boltz: 1.1
    ChimeraX-BondRot: 2.0.4
    ChimeraX-BugReporter: 1.0.2
    ChimeraX-BuildStructure: 2.13.1
    ChimeraX-Bumps: 1.0
    ChimeraX-BundleBuilder: 1.6.0
    ChimeraX-ButtonPanel: 1.0.1
    ChimeraX-CageBuilder: 1.0.1
    ChimeraX-CellPack: 1.0
    ChimeraX-Centroids: 1.4.1
    ChimeraX-ChangeChains: 1.1
    ChimeraX-CheckWaters: 1.5
    ChimeraX-ChemGroup: 2.0.2
    ChimeraX-Clashes: 2.3
    ChimeraX-ColorActions: 1.0.5
    ChimeraX-ColorGlobe: 1.0
    ChimeraX-ColorKey: 1.5.8
    ChimeraX-CommandLine: 1.3.1
    ChimeraX-ConnectStructure: 2.0.1
    ChimeraX-Contacts: 1.0.1
    ChimeraX-Core: 1.12.dev202602142240
    ChimeraX-CoreFormats: 1.2
    ChimeraX-coulombic: 1.4.5
    ChimeraX-Crosslinks: 1.0
    ChimeraX-Crystal: 1.0
    ChimeraX-CrystalContacts: 1.0.1
    ChimeraX-DataFormats: 1.2.4
    ChimeraX-Dicom: 1.2.7
    ChimeraX-DistMonitor: 1.4.2
    ChimeraX-DockPrep: 1.2
    ChimeraX-Dssp: 2.0
    ChimeraX-EMDB-SFF: 1.0
    ChimeraX-ESMFold: 1.0
    ChimeraX-FileHistory: 1.0.1
    ChimeraX-FunctionKey: 1.0.1
    ChimeraX-Geometry: 1.3
    ChimeraX-gltf: 1.0
    ChimeraX-Graphics: 1.4.1
    ChimeraX-Hbonds: 2.5.3
    ChimeraX-Help: 1.3
    ChimeraX-HKCage: 1.3
    ChimeraX-IHM: 1.1
    ChimeraX-ImageFormats: 1.2
    ChimeraX-IMOD: 1.0
    ChimeraX-IO: 1.0.4
    ChimeraX-ItemsInspection: 1.0.1
    ChimeraX-IUPAC: 1.0
    ChimeraX-KVFinder: 1.8.2
    ChimeraX-Label: 1.3
    ChimeraX-LightingGUI: 1.0
    ChimeraX-ListInfo: 1.3.1
    ChimeraX-Log: 1.2.2
    ChimeraX-LookingGlass: 1.1
    ChimeraX-Maestro: 1.9.2
    ChimeraX-Map: 1.3
    ChimeraX-MapData: 2.0
    ChimeraX-MapEraser: 1.0.1
    ChimeraX-MapFilter: 2.0.1
    ChimeraX-MapFit: 2.0
    ChimeraX-MapSeries: 2.1.1
    ChimeraX-Markers: 1.0.1
    ChimeraX-Mask: 1.0.2
    ChimeraX-MatchMaker: 2.2.2
    ChimeraX-MCopy: 1.0
    ChimeraX-MCPServer: 0.2.0
    ChimeraX-MDcrds: 2.17.2
    ChimeraX-MedicalToolbar: 1.1
    ChimeraX-Meeting: 1.0.1
    ChimeraX-Minimize: 1.3.5
    ChimeraX-MLP: 1.1.1
    ChimeraX-mmCIF: 2.16
    ChimeraX-MMTF: 2.2
    ChimeraX-ModelArchive: 1.0
    ChimeraX-Modeller: 1.5.23
    ChimeraX-ModelPanel: 1.6.1
    ChimeraX-ModelSeries: 1.0.1
    ChimeraX-Mol2: 2.0.3
    ChimeraX-Mole: 1.0
    ChimeraX-Morph: 1.0.2
    ChimeraX-MouseModes: 1.2
    ChimeraX-Movie: 1.0.1
    ChimeraX-MutationScores: 1.0
    ChimeraX-Neuron: 1.0
    ChimeraX-Nifti: 1.2
    ChimeraX-NMRSTAR: 1.0.2
    ChimeraX-NRRD: 1.2
    ChimeraX-Nucleotides: 2.0.3
    ChimeraX-OpenCommand: 1.15.2
    ChimeraX-OpenFold: 1.0
    ChimeraX-OrthoPick: 1.0.1
    ChimeraX-PDB: 2.7.12
    ChimeraX-PDBBio: 1.0.1
    ChimeraX-PDBLibrary: 1.0.5
    ChimeraX-PDBMatrices: 1.0
    ChimeraX-PickBlobs: 1.0.1
    ChimeraX-Positions: 1.0
    ChimeraX-PresetMgr: 1.1.4
    ChimeraX-ProfileGrids: 1.5.1
    ChimeraX-PubChem: 2.2
    ChimeraX-ReadPbonds: 1.0.1
    ChimeraX-Registration: 1.1.2
    ChimeraX-RemoteControl: 1.0
    ChimeraX-RenderByAttr: 1.8
    ChimeraX-RenumberResidues: 1.1
    ChimeraX-ResidueFit: 1.0.1
    ChimeraX-RestServer: 1.3.3
    ChimeraX-RNALayout: 1.0
    ChimeraX-RotamerLibMgr: 4.0
    ChimeraX-RotamerLibsDunbrack: 2.0
    ChimeraX-RotamerLibsDynameomics: 2.0
    ChimeraX-RotamerLibsRichardson: 2.0
    ChimeraX-SaveCommand: 1.5.2
    ChimeraX-Scenes: 0.3.1
    ChimeraX-SchemeMgr: 1.0
    ChimeraX-SDF: 2.0.3
    ChimeraX-Segger: 1.0
    ChimeraX-Segment: 1.0.1
    ChimeraX-Segmentations: 3.5.12
    ChimeraX-SelInspector: 1.0
    ChimeraX-SeqView: 2.17.5
    ChimeraX-Shape: 1.1
    ChimeraX-Shell: 1.0.1
    ChimeraX-Shortcuts: 1.2.1
    ChimeraX-ShowSequences: 1.0.3
    ChimeraX-SideView: 1.0.1
    ChimeraX-SimilarStructures: 1.0.1
    ChimeraX-Smiles: 2.1.2
    ChimeraX-SmoothLines: 1.0
    ChimeraX-SNFG: 1.0
    ChimeraX-SpaceNavigator: 1.0
    ChimeraX-StdCommands: 1.19.3
    ChimeraX-STL: 1.0.1
    ChimeraX-Storm: 1.0
    ChimeraX-StructMeasure: 1.2.1
    ChimeraX-Struts: 1.0.1
    ChimeraX-Surface: 1.0.1
    ChimeraX-SwapAA: 2.0.1
    ChimeraX-SwapRes: 2.5.2
    ChimeraX-TapeMeasure: 1.0
    ChimeraX-TaskManager: 1.0
    ChimeraX-Test: 1.0
    ChimeraX-Toolbar: 1.2.3
    ChimeraX-ToolshedUtils: 1.2.4
    ChimeraX-Topography: 1.0
    ChimeraX-ToQuest: 1.0
    ChimeraX-Tug: 1.0.1
    ChimeraX-UI: 1.50.1
    ChimeraX-Umap: 1.0
    ChimeraX-uniprot: 2.3.2
    ChimeraX-UnitCell: 1.0.1
    ChimeraX-ViewDock: 1.6
    ChimeraX-VIPERdb: 1.0
    ChimeraX-Vive: 1.1
    ChimeraX-VolumeMenu: 1.0.1
    ChimeraX-vrml: 1.0
    ChimeraX-VTK: 1.0
    ChimeraX-WavefrontOBJ: 1.0
    ChimeraX-WebCam: 1.0.2
    ChimeraX-WebServices: 1.1.5
    ChimeraX-Zone: 1.0.1
    click: 8.3.1
    colorama: 0.4.6
    comm: 0.2.3
    contourpy: 1.3.3
    coverage: 7.13.4
    cxservices: 1.2.3
    cycler: 0.12.1
    Cython: 3.1.4
    debugpy: 1.8.20
    decorator: 5.2.1
    docutils: 0.21.2
    executing: 2.2.1
    filelock: 3.19.1
    fonttools: 4.61.1
    frozenlist: 1.8.0
    funcparserlib: 2.0.0a0
    glfw: 2.10.0
    grako: 3.16.5
    h11: 0.16.0
    h5py: 3.15.1
    html2text: 2025.4.15
    httpcore: 1.0.9
    httpx: 0.28.1
    httpx-sse: 0.4.3
    idna: 3.11
    ihm: 2.2
    imagecodecs: 2024.6.1
    imagesize: 1.4.1
    iniconfig: 2.3.0
    ipykernel: 7.1.0
    ipython: 9.9.0
    ipython_pygments_lexers: 1.1.1
    ipywidgets: 8.1.8
    jedi: 0.19.2
    Jinja2: 3.1.6
    jsonschema: 4.26.0
    jsonschema-specifications: 2025.9.1
    jupyter_client: 8.8.0
    jupyter_core: 5.9.1
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    lz4: 4.3.2
    Markdown: 3.8.2
    MarkupSafe: 3.0.3
    matplotlib: 3.10.7
    matplotlib-inline: 0.2.1
    mcp: 1.18.0
    msgpack: 1.1.1
    multidict: 6.7.1
    ndindex: 1.10.1
    nest-asyncio: 1.6.0
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    nibabel: 5.2.0
    nptyping: 2.5.0
    numexpr: 2.14.1
    numpy: 1.26.4
    OpenMM: 8.4.0
    openvr: 1.26.701
    packaging: 25.0
    ParmEd: 4.2.2
    parso: 0.8.6
    pep517: 0.13.1
    pexpect: 4.9.0
    pickleshare: 0.7.5
    pillow: 11.3.0
    pip: 25.2
    pkginfo: 1.12.1.2
    platformdirs: 4.9.1
    pluggy: 1.6.0
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    ptyprocess: 0.7.0
    pure_eval: 0.2.3
    py-cpuinfo: 9.0.0
    pybind11: 3.0.1
    pycollada: 0.8
    pydantic: 2.12.5
    pydantic-settings: 2.12.0
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    pydicom: 2.4.4
    Pygments: 2.18.0
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    pynrrd: 1.0.0
    PyOpenGL: 3.1.10
    PyOpenGL-accelerate: 3.1.10
    pyopenxr: 1.1.4501
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    PySide6: 6.10.1
    PySide6_Addons: 6.10.1
    PySide6_Essentials: 6.10.1
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    pytest-cov: 7.0.0
    python-dateutil: 2.9.0.post0
    python-dotenv: 1.2.1
    python-multipart: 0.0.22
    pyzmq: 27.1.0
    qtconsole: 5.7.0
    QtPy: 2.4.3
    qtshim: 1.2.1
    RandomWords: 0.4.0
    referencing: 0.37.0
    requests: 2.32.5
    roman-numerals: 4.1.0
    rpds-py: 0.30.0
    scipy: 1.14.0
    setuptools: 80.9.0
    sfftk-rw: 0.8.1
    shiboken6: 6.10.1
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    soupsieve: 2.8.3
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    tcia_utils: 1.5.1
    tifffile: 2025.3.13
    tinyarray: 1.2.5
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