Can't select atom with empty chain id

[goddard@…]

The following bug report has been submitted:
Platform:        macOS-10.15.7-x86_64-i386-64bit
ChimeraX Version: 1.2.dev202101290243 (2021-01-29 02:43:44 UTC)
Description
Ctrl-click to select an atom produces an invalid select command if the chain identifier is the empty string.  Also it produces an error if the serial number has not been set.  I was looking at a molecule made from a Gaussian cube file (small molecule) using a Python script.  I attach an mmCIF version that has serial numbers but no chain id.

Log:
UCSF ChimeraX version: 1.2.dev202101290243 (2021-01-29)  
© 2016-2020 Regents of the University of California. All rights reserved.  
How to cite UCSF ChimeraX  

> open /Users/goddard/Downloads/wfc_K001_B329wfc.cube

Opened wfc_K001_B329wfc.cube as #1, grid size 360,360,360, pixel 0.0321, shown
at level -0.00109,0.00109, step 2, values float32  

> open
> /Users/goddard/ucsf/chimerax/src/bundles/map_data/src/gaussian/make_atoms.py

Created 1 atomic models for 1 Gaussian Cube files  
executed make_atoms.py  

> select /:1@@serial_number=-1

Expected an objects specifier or a keyword  

> select /:1@@serial_number=-1

Expected an objects specifier or a keyword  

> select /:1@@serial_number=-1

Expected an objects specifier or a keyword  

> close #2

> open
> /Users/goddard/ucsf/chimerax/src/bundles/map_data/src/gaussian/make_atoms.py

Created 1 atomic models for 1 Gaussian Cube files  
executed make_atoms.py  
Drag select of 2 atoms  

> select /:1@@serial_number=90

Expected an objects specifier or a keyword  

> select /A:1@@serial_number=90

Nothing selected  
Drag select of 20 atoms  

> save /Users/goddard/Desktop/test.mmcif models #2

> open /Users/goddard/Desktop/test.mmcif format mmcif

Summary of feedback from opening /Users/goddard/Desktop/test.mmcif  
---  
warnings | Unable to infer polymer connectivity due to unspecified
label_seq_id for residue "UNK" near line 90  
Atom Al is not in the residue template for UNK /:1  
  

> hide #2 models

> select #3/:1@@serial_number=58

Expected an objects specifier or a keyword  




OpenGL version: 4.1 ATI-3.10.18
OpenGL renderer: AMD Radeon Pro Vega 20 OpenGL Engine
OpenGL vendor: ATI Technologies Inc.Hardware:

    Hardware Overview:

      Model Name: MacBook Pro
      Model Identifier: MacBookPro15,3
      Processor Name: 8-Core Intel Core i9
      Processor Speed: 2.4 GHz
      Number of Processors: 1
      Total Number of Cores: 8
      L2 Cache (per Core): 256 KB
      L3 Cache: 16 MB
      Hyper-Threading Technology: Enabled
      Memory: 32 GB
      Boot ROM Version: 1037.147.4.0.0 (iBridge: 17.16.16610.0.0,0)

Software:

    System Software Overview:

      System Version: macOS 10.15.7 (19H2)
      Kernel Version: Darwin 19.6.0
      Time since boot: 49 days 10:42

Graphics/Displays:

    Intel UHD Graphics 630:

      Chipset Model: Intel UHD Graphics 630
      Type: GPU
      Bus: Built-In
      VRAM (Dynamic, Max): 1536 MB
      Vendor: Intel
      Device ID: 0x3e9b
      Revision ID: 0x0002
      Automatic Graphics Switching: Supported
      gMux Version: 5.0.0
      Metal: Supported, feature set macOS GPUFamily2 v1

    Radeon Pro Vega 20:

      Chipset Model: Radeon Pro Vega 20
      Type: GPU
      Bus: PCIe
      PCIe Lane Width: x8
      VRAM (Total): 4 GB
      Vendor: AMD (0x1002)
      Device ID: 0x69af
      Revision ID: 0x00c0
      ROM Revision: 113-D2060I-087
      VBIOS Version: 113-D20601MA0T-016
      Option ROM Version: 113-D20601MA0T-016
      EFI Driver Version: 01.01.087
      Automatic Graphics Switching: Supported
      gMux Version: 5.0.0
      Metal: Supported, feature set macOS GPUFamily2 v1
      Displays:
        Color LCD:
          Display Type: Built-In Retina LCD
          Resolution: 2880 x 1800 Retina
          Framebuffer Depth: 24-Bit Color (ARGB8888)
          Main Display: Yes
          Mirror: Off
          Online: Yes
          Automatically Adjust Brightness: No
          Connection Type: Internal

Locale: ('en_US', 'UTF-8')
PyQt5 5.15.2, Qt 5.15.2
Installed Packages:
    alabaster: 0.7.12
    appdirs: 1.4.4
    appnope: 0.1.2
    Babel: 2.9.0
    backcall: 0.2.0
    biopython: 1.78
    blockdiag: 2.0.1
    certifi: 2020.12.5
    cftime: 1.3.1
    chardet: 3.0.4
    ChimeraX-AddCharge: 1.0
    ChimeraX-AddH: 2.1.3
    ChimeraX-AlignmentAlgorithms: 2.0
    ChimeraX-AlignmentHdrs: 3.2
    ChimeraX-AlignmentMatrices: 2.0
    ChimeraX-Alignments: 2.1
    ChimeraX-AmberInfo: 1.0
    ChimeraX-Arrays: 1.0
    ChimeraX-Atomic: 1.11
    ChimeraX-AtomicLibrary: 1.2
    ChimeraX-AtomSearch: 2.0
    ChimeraX-AtomSearchLibrary: 1.0
    ChimeraX-AxesPlanes: 2.0
    ChimeraX-BasicActions: 1.1
    ChimeraX-BILD: 1.0
    ChimeraX-BlastProtein: 1.1
    ChimeraX-BondRot: 2.0
    ChimeraX-BugReporter: 1.0
    ChimeraX-BuildStructure: 2.4
    ChimeraX-Bumps: 1.0
    ChimeraX-BundleBuilder: 1.1
    ChimeraX-ButtonPanel: 1.0
    ChimeraX-CageBuilder: 1.0
    ChimeraX-CellPack: 1.0
    ChimeraX-Centroids: 1.1
    ChimeraX-ChemGroup: 2.0
    ChimeraX-Clashes: 2.1
    ChimeraX-ColorActions: 1.0
    ChimeraX-ColorGlobe: 1.0
    ChimeraX-CommandLine: 1.1.3
    ChimeraX-ConnectStructure: 2.0
    ChimeraX-Contacts: 1.0
    ChimeraX-Core: 1.2.dev202101290243
    ChimeraX-CoreFormats: 1.0
    ChimeraX-coulombic: 1.0.3
    ChimeraX-Crosslinks: 1.0
    ChimeraX-Crystal: 1.0
    ChimeraX-DataFormats: 1.1
    ChimeraX-Dicom: 1.0
    ChimeraX-DistMonitor: 1.1
    ChimeraX-DistUI: 1.0
    ChimeraX-Dssp: 2.0
    ChimeraX-EMDB-SFF: 1.0
    ChimeraX-ExperimentalCommands: 1.0
    ChimeraX-FileHistory: 1.0
    ChimeraX-FunctionKey: 1.0
    ChimeraX-Geometry: 1.1
    ChimeraX-gltf: 1.0
    ChimeraX-Graphics: 1.0
    ChimeraX-Hbonds: 2.1
    ChimeraX-Help: 1.1
    ChimeraX-HKCage: 1.3
    ChimeraX-IHM: 1.0
    ChimeraX-ImageFormats: 1.1
    ChimeraX-IMOD: 1.0
    ChimeraX-IO: 1.0
    ChimeraX-Label: 1.0
    ChimeraX-ListInfo: 1.1
    ChimeraX-Log: 1.1.1
    ChimeraX-LookingGlass: 1.1
    ChimeraX-Maestro: 1.8.1
    ChimeraX-Map: 1.0.2
    ChimeraX-MapData: 2.0
    ChimeraX-MapEraser: 1.0
    ChimeraX-MapFilter: 2.0
    ChimeraX-MapFit: 2.0
    ChimeraX-MapSeries: 2.0
    ChimeraX-Markers: 1.0
    ChimeraX-Mask: 1.0
    ChimeraX-MatchMaker: 1.1
    ChimeraX-MDcrds: 2.2
    ChimeraX-MedicalToolbar: 1.0.1
    ChimeraX-Meeting: 1.0
    ChimeraX-MLP: 1.0
    ChimeraX-mmCIF: 2.2
    ChimeraX-MMTF: 2.0
    ChimeraX-Modeller: 1.0
    ChimeraX-ModelPanel: 1.0.1
    ChimeraX-ModelSeries: 1.0
    ChimeraX-Mol2: 2.0
    ChimeraX-Morph: 1.0
    ChimeraX-MouseModes: 1.0
    ChimeraX-Movie: 1.0
    ChimeraX-Neuron: 1.0
    ChimeraX-Nucleotides: 2.0
    ChimeraX-OpenCommand: 1.5
    ChimeraX-PDB: 2.2
    ChimeraX-PDBBio: 1.0
    ChimeraX-PDBLibrary: 1.0
    ChimeraX-PickBlobs: 1.0
    ChimeraX-Positions: 1.0
    ChimeraX-PresetMgr: 1.0.1
    ChimeraX-PubChem: 2.0.1
    ChimeraX-ReadPbonds: 1.0
    ChimeraX-Registration: 1.1
    ChimeraX-RemoteControl: 1.0
    ChimeraX-ResidueFit: 1.0
    ChimeraX-RestServer: 1.1
    ChimeraX-RNALayout: 1.0
    ChimeraX-RotamerLibMgr: 2.0
    ChimeraX-RotamerLibsDunbrack: 2.0
    ChimeraX-RotamerLibsDynameomics: 2.0
    ChimeraX-RotamerLibsRichardson: 2.0
    ChimeraX-SaveCommand: 1.4
    ChimeraX-SchemeMgr: 1.0
    ChimeraX-SDF: 2.0
    ChimeraX-Segger: 1.0
    ChimeraX-Segment: 1.0
    ChimeraX-SeqView: 2.3
    ChimeraX-Shape: 1.0.1
    ChimeraX-Shell: 1.0
    ChimeraX-Shortcuts: 1.0
    ChimeraX-ShowAttr: 1.0
    ChimeraX-ShowSequences: 1.0
    ChimeraX-SideView: 1.0
    ChimeraX-Smiles: 2.0.1
    ChimeraX-SmoothLines: 1.0
    ChimeraX-SpaceNavigator: 1.0
    ChimeraX-StdCommands: 1.3
    ChimeraX-STL: 1.0
    ChimeraX-Storm: 1.0
    ChimeraX-Struts: 1.0
    ChimeraX-Surface: 1.0
    ChimeraX-SwapAA: 2.0
    ChimeraX-SwapRes: 2.1
    ChimeraX-TapeMeasure: 1.0
    ChimeraX-Test: 1.0
    ChimeraX-Toolbar: 1.0
    ChimeraX-ToolshedUtils: 1.1
    ChimeraX-Tug: 1.0
    ChimeraX-UI: 1.6
    ChimeraX-uniprot: 2.1
    ChimeraX-ViewDockX: 1.0
    ChimeraX-Vive: 1.1
    ChimeraX-VolumeMenu: 1.0
    ChimeraX-VTK: 1.0
    ChimeraX-WavefrontOBJ: 1.0
    ChimeraX-WebCam: 1.0
    ChimeraX-WebServices: 1.0
    ChimeraX-Zone: 1.0
    colorama: 0.4.3
    comtypes: 1.1.7
    cxservices: 1.0
    cycler: 0.10.0
    Cython: 0.29.21
    decorator: 4.4.2
    distlib: 0.3.1
    docutils: 0.16
    filelock: 3.0.12
    flake8: 3.8.3
    flake8-polyfill: 1.0.2
    funcparserlib: 0.3.6
    grako: 3.16.5
    h5py: 2.10.0
    html2text: 2020.1.16
    idna: 2.10
    ihm: 0.17
    imagecodecs: 2020.5.30
    imagesize: 1.2.0
    ipykernel: 5.3.4
    ipython: 7.18.1
    ipython-genutils: 0.2.0
    jedi: 0.17.2
    Jinja2: 2.11.2
    jupyter-client: 6.1.7
    jupyter-core: 4.7.0
    kiwisolver: 1.3.1
    line-profiler: 2.1.2
    lxml: 4.6.2
    lz4: 3.1.0
    MarkupSafe: 1.1.1
    matplotlib: 3.3.2
    mccabe: 0.6.1
    MolecularDynamicsViewer: 1.1
    msgpack: 1.0.0
    netCDF4: 1.5.4
    networkx: 2.5
    numexpr: 2.7.2
    numpy: 1.19.2
    numpydoc: 1.1.0
    openvr: 1.14.1501
    packaging: 20.8
    ParmEd: 3.2.0
    parso: 0.7.1
    pep8: 1.7.1
    pep8-naming: 0.10.0
    pexpect: 4.8.0
    pickleshare: 0.7.5
    Pillow: 7.2.0
    pip: 20.3.1
    pkginfo: 1.5.0.1
    prompt-toolkit: 3.0.14
    psutil: 5.7.2
    ptyprocess: 0.7.0
    pycodestyle: 2.6.0
    pycollada: 0.7.1
    pydicom: 2.0.0
    pyflakes: 2.2.0
    Pygments: 2.7.1
    PyOpenGL: 3.1.5
    PyOpenGL-accelerate: 3.1.5
    pyparsing: 2.4.7
    PyQt5: 5.15.2
    PyQt5-sip: 12.8.1
    PyQtWebEngine: 5.15.2
    python-dateutil: 2.8.1
    pytz: 2020.1
    pyzmq: 22.0.0
    qtconsole: 4.7.7
    QtPy: 1.9.0
    RandomWords: 0.3.0
    requests: 2.24.0
    scipy: 1.5.2
    Send2Trash: 1.5.0
    setuptools: 50.3.2
    sfftk-rw: 0.6.7.dev1
    six: 1.15.0
    snowballstemmer: 2.1.0
    sortedcontainers: 2.2.2
    Sphinx: 3.2.1
    sphinxcontrib-applehelp: 1.0.2
    sphinxcontrib-blockdiag: 2.0.0
    sphinxcontrib-devhelp: 1.0.2
    sphinxcontrib-htmlhelp: 1.0.3
    sphinxcontrib-jsmath: 1.0.1
    sphinxcontrib-qthelp: 1.0.3
    sphinxcontrib-serializinghtml: 1.1.4
    suds-jurko: 0.6
    tables: 3.6.1
    tifffile: 2020.9.3
    tinyarray: 1.2.3
    tornado: 6.1
    traitlets: 5.0.5
    urllib3: 1.25.11
    wcwidth: 0.2.5
    webcolors: 1.11.1
    wheel: 0.36.0
    wheel-filename: 1.2.0
File attachment: test.mmcif

test.mmcif​

[goddard@…]

Added by email2trac

[Tom Goddard]

The problem here is that Atom.string(style='command') is returning an illegal specifier when the chain id is an empty string.

For model in this bug had no way of identifying the atoms by a specifier because it did not have atom serial numbers and lots of atoms had the same name in the same residue (from an inorganic crystal unit cell). I fixed the script that created the atoms from a Gaussian cube file so it assigned serial numbers and also used chain id A.

[Eric Pettersen]

The real underlying problem is that there is no way to specify a blank chain ID in a legal atom specifier, including various uses of quotation marks. Allowing the space character as a chain ID doesn't play well with the lexer/parser because unquoted spaces are ignored (and you can't quote a chain ID because unfortunately quotation marks themselves are legal chain IDs).

What I can do is use '?' instead of space. Hopefully structures like these only have spaces and not a mix (I have never seen a file with a mix). Though not perfect, it would certainly be a step forward.

File readers need to assign serial numbers, particularly if there are atoms of the same name in the same residue. Otherwise there simply is no atom spec to specify a single atom. You have fixed your script so it's moot.

[Eric Pettersen]

FYI, if you had used atomic.struct_edit.add_atom to add your atoms, the serial numbering would have been handled automatically.

[Eric Pettersen]

Okay, made it so that if the chain ID is a blank, then the atom spec uses "/?". Unfortunately, your example file doesn't set the chain ID to a blank, it sets it to the empty string. Not even "/?" matches an empty chain ID. I changed atomic to reject empty chain IDs.

I unwittingly put the changes on my color-key branch, so it'll be a day or two before they actually get pushed.

[goddard@…]

Ok, all sounds reasonable.  This was of course a perverse case with empty chain id.