Fix summary when optimizer is None

[mattdangerw]

Optimizer can be None (e.g. for just running inference). We should be careful not to assume it is always set when printing out model summary.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (beba6f1) 76.49% compared to head (060560c) 76.49%.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #879   +/-   ##
=======================================
  Coverage   76.49%   76.49%           
=======================================
  Files         329      329           
  Lines       31334    31334           
  Branches     6100     6100           
=======================================
  Hits        23970    23970           
  Misses       5785     5785           
  Partials     1579     1579           

Flag	Coverage Δ
keras_core	76.40% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
keras_core/utils/summary_utils.py	72.72% <100.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[fchollet]

LGTM, thanks for the fix!

[fchollet]

FAILED keras_core/utils/summary_utils_test.py::SummaryUtilsTest::test_print_model_summary0 - NotImplementedError: fit not implemented for NumPy backend.

We should exclude the Numpy backend in the test.

[fchollet]

LGTM