iris.util.broadcast_to_shape does not work with lazy data #5295
Description
🐛 Bug Report
How To Reproduce
Steps to reproduce the behaviour:
Run the following code:
>>> import dask.array as da
>>> from iris.util import broadcast_to_shape
>>> a = da.array([[1, 2, 3], [4, 5, 6]])
>>> b = broadcast_to_shape(a, (5, 2, 6, 3), (1, 3))
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/bandela/mambaforge/envs/test/lib/python3.11/site-packages/iris/util.py", line 98, in broadcast_to_shape
array_view = _broadcast_helper(array)
^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/bandela/mambaforge/envs/test/lib/python3.11/site-packages/iris/util.py", line 95, in _broadcast_helper
strides[dim] = a.strides[idim]
^^^^^^^^^
AttributeError: 'Array' object has no attribute 'strides'Expected behaviour
The function documentation mentions that "This function maintains laziness when called; it does not realise data.", so I would expect the function to return a Dask array instead of crash when following the example from the docstring with a dask array as input.
Screenshots
Environment
- OS & Version: Ubuntu 23.04
- Iris Version: 3.5
$ mamba env export
gives
name: test
channels:
- conda-forge
dependencies:
- _libgcc_mutex=0.1=conda_forge
- _openmp_mutex=4.5=2_gnu
- antlr-python-runtime=4.7.2=py311h38be061_1003
- brotli=1.0.9=h166bdaf_8
- brotli-bin=1.0.9=h166bdaf_8
- brotlipy=0.7.0=py311hd4cff14_1005
- bzip2=1.0.8=h7f98852_4
- c-ares=1.18.1=h7f98852_0
- ca-certificates=2022.12.7=ha878542_0
- cartopy=0.21.1=py311hd88b842_1
- certifi=2022.12.7=pyhd8ed1ab_0
- cf-units=3.2.0=py311hcb2cf0a_0
- cffi=1.15.1=py311h409f033_3
- cftime=1.6.2=py311h4c7f6c3_1
- charset-normalizer=3.1.0=pyhd8ed1ab_0
- click=8.1.3=unix_pyhd8ed1ab_2
- cloudpickle=2.2.1=pyhd8ed1ab_0
- contourpy=1.0.7=py311ha3edf6b_0
- cryptography=40.0.2=py311h9b4c7bb_0
- curl=8.0.1=h588be90_0
- cycler=0.11.0=pyhd8ed1ab_0
- dask-core=2023.4.1=pyhd8ed1ab_0
- expat=2.5.0=hcb278e6_1
- fonttools=4.39.3=py311h2582759_0
- freetype=2.12.1=hca18f0e_1
- fsspec=2023.4.0=pyh1a96a4e_0
- geos=3.11.2=hcb278e6_0
- hdf4=4.2.15=h9772cbc_5
- hdf5=1.12.2=nompi_h4df4325_101
- icu=72.1=hcb278e6_0
- idna=3.4=pyhd8ed1ab_0
- importlib-metadata=6.6.0=pyha770c72_0
- importlib_metadata=6.6.0=hd8ed1ab_0
- iris=3.5.0=pyhd8ed1ab_0
- jinja2=3.1.2=pyhd8ed1ab_1
- jpeg=9e=h0b41bf4_3
- keyutils=1.6.1=h166bdaf_0
- kiwisolver=1.4.4=py311h4dd048b_1
- krb5=1.20.1=h81ceb04_0
- lcms2=2.15=hfd0df8a_0
- ld_impl_linux-64=2.40=h41732ed_0
- lerc=4.0.0=h27087fc_0
- libaec=1.0.6=hcb278e6_1
- libblas=3.9.0=16_linux64_openblas
- libbrotlicommon=1.0.9=h166bdaf_8
- libbrotlidec=1.0.9=h166bdaf_8
- libbrotlienc=1.0.9=h166bdaf_8
- libcblas=3.9.0=16_linux64_openblas
- libcurl=8.0.1=h588be90_0
- libdeflate=1.17=h0b41bf4_0
- libedit=3.1.20191231=he28a2e2_2
- libev=4.33=h516909a_1
- libexpat=2.5.0=hcb278e6_1
- libffi=3.4.2=h7f98852_5
- libgcc-ng=12.2.0=h65d4601_19
- libgfortran-ng=12.2.0=h69a702a_19
- libgfortran5=12.2.0=h337968e_19
- libgomp=12.2.0=h65d4601_19
- libiconv=1.17=h166bdaf_0
- liblapack=3.9.0=16_linux64_openblas
- libnetcdf=4.8.1=nompi_h261ec11_106
- libnghttp2=1.52.0=h61bc06f_0
- libnsl=2.0.0=h7f98852_0
- libopenblas=0.3.21=pthreads_h78a6416_3
- libpng=1.6.39=h753d276_0
- libsqlite=3.40.0=h753d276_1
- libssh2=1.10.0=hf14f497_3
- libstdcxx-ng=12.2.0=h46fd767_19
- libtiff=4.5.0=h6adf6a1_2
- libuuid=2.38.1=h0b41bf4_0
- libwebp-base=1.3.0=h0b41bf4_0
- libxcb=1.13=h7f98852_1004
- libxml2=2.10.4=hfdac1af_0
- libzip=1.9.2=hc929e4a_1
- libzlib=1.2.13=h166bdaf_4
- locket=1.0.0=pyhd8ed1ab_0
- markupsafe=2.1.2=py311h2582759_0
- matplotlib-base=3.7.1=py311h8597a09_0
- munkres=1.1.4=pyh9f0ad1d_0
- ncurses=6.3=h27087fc_1
- netcdf4=1.6.2=nompi_py311hc6fcf29_100
- numpy=1.24.3=py311h64a7726_0
- openjpeg=2.5.0=hfec8fc6_2
- openssl=3.1.0=hd590300_2
- packaging=23.1=pyhd8ed1ab_0
- partd=1.4.0=pyhd8ed1ab_0
- pillow=9.4.0=py311h50def17_1
- pip=23.1.2=pyhd8ed1ab_0
- platformdirs=3.5.0=pyhd8ed1ab_0
- pooch=1.7.0=pyha770c72_3
- proj=9.2.0=h8ffa02c_0
- pthread-stubs=0.4=h36c2ea0_1001
- pycparser=2.21=pyhd8ed1ab_0
- pyopenssl=23.1.1=pyhd8ed1ab_0
- pyparsing=3.0.9=pyhd8ed1ab_0
- pyproj=3.5.0=py311h1850bce_1
- pyshp=2.3.1=pyhd8ed1ab_0
- pysocks=1.7.1=pyha2e5f31_6
- python=3.11.3=h2755cc3_0_cpython
- python-dateutil=2.8.2=pyhd8ed1ab_0
- python-xxhash=3.2.0=py311h2582759_0
- python_abi=3.11=3_cp311
- pyyaml=6.0=py311hd4cff14_5
- readline=8.2=h8228510_1
- requests=2.29.0=pyhd8ed1ab_0
- scipy=1.10.1=py311h8e6699e_0
- setuptools=67.7.2=pyhd8ed1ab_0
- shapely=2.0.1=py311h54d622a_1
- six=1.16.0=pyh6c4a22f_0
- sqlite=3.40.0=h4ff8645_1
- tk=8.6.12=h27826a3_0
- toolz=0.12.0=pyhd8ed1ab_0
- typing-extensions=4.5.0=hd8ed1ab_0
- typing_extensions=4.5.0=pyha770c72_0
- tzdata=2023c=h71feb2d_0
- udunits2=2.2.28=hc3e0081_0
- urllib3=1.26.15=pyhd8ed1ab_0
- wheel=0.40.0=pyhd8ed1ab_0
- xorg-libxau=1.0.9=h7f98852_0
- xorg-libxdmcp=1.1.3=h7f98852_0
- xxhash=0.8.1=h0b41bf4_0
- xz=5.2.6=h166bdaf_0
- yaml=0.2.5=h7f98852_2
- zipp=3.15.0=pyhd8ed1ab_0
- zlib=1.2.13=h166bdaf_4
- zstd=1.5.2=h3eb15da_6
Additional context
Click to expand this section...
Please add additional verbose information in this section e.g., code, output, tracebacks, screenshots etc