Make _metadata regular JSONType field

[mvdbeek]

What did you do?

• Make _metadata regular JSONType field

Why did you make this change?

#11885 made it very obvious that there is a lot of overhead with the nested mutable json tracking. I believe setting metadata doesn't really require the nested tracking that the MutableJSONType field gives us.

How to test the changes?

(select the most appropriate option; if the latter, provide steps for testing below)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these contributions under Galaxy's current license.
• I agree to allow the Galaxy committers to license these and all my past contributions to the core galaxy codebase under the MIT license. If this condition is an issue, uncheck and just let us know why with an e-mail to galaxy-committers@lists.galaxyproject.org.

For UI Components

• I've included a screenshot of the changes

[mvdbeek]

This is together with #11901, closing and expanding the test dataset 6 times from #11885. :

make_html_table (lib/galaxy/datatypes/tabular.py:131)
function called 6 times

         12132 function calls in 0.011 seconds

   Ordered by: cumulative time, internal time, call count

   ncalls  tottime  percall  cumtime  percall filename:lineno(function)
        6    0.000    0.000    0.011    0.002 tabular.py:131(make_html_table)
        6    0.002    0.000    0.008    0.001 tabular.py:191(make_html_peek_rows)
     1800    0.003    0.000    0.005    0.000 {built-in method markupsafe._speedups.escape}
        6    0.001    0.000    0.003    0.001 tabular.py:144(make_html_peek_header)
       54    0.001    0.000    0.003    0.000 metadata.py:119(__getattr__)
     1800    0.001    0.000    0.002    0.000 __init__.py:70(__new__)
      114    0.000    0.000    0.001    0.000 metadata.py:87(spec)
      114    0.000    0.000    0.001    0.000 __init__.py:2838(datatype)
      114    0.000    0.000    0.001    0.000 __init__.py:2720(datatype_for_extension)
     1800    0.000    0.000    0.000    0.000 {built-in method __new__ of type object at 0x10fdea420}
       54    0.000    0.000    0.000    0.000 session.py:3453(object_session)
     2490    0.000    0.000    0.000    0.000 {method 'append' of 'list' objects}
       60    0.000    0.000    0.000    0.000 __init__.py:2842(get_metadata)
      336    0.000    0.000    0.000    0.000 metadata.py:75(get_parent)
      234    0.000    0.000    0.000    0.000 attributes.py:286(__get__)
     1860    0.000    0.000    0.000    0.000 {built-in method builtins.hasattr}
       54    0.000    0.000    0.000    0.000 session.py:45(_state_session)
      300    0.000    0.000    0.000    0.000 {method 'format' of 'str' objects}
       54    0.000    0.000    0.000    0.000 metadata.py:364(wrap)
       30    0.000    0.000    0.000    0.000 {method 'split' of 'str' objects}
      114    0.000    0.000    0.000    0.000 registry.py:579(get_datatype_by_extension)
       54    0.000    0.000    0.000    0.000 weakref.py:131(__getitem__)
      114    0.000    0.000    0.000    0.000 __init__.py:132(_get_datatypes_registry)
       12    0.000    0.000    0.000    0.000 __init__.py:2779(peek)
       18    0.000    0.000    0.000    0.000 {method 'join' of 'str' objects}
      120    0.000    0.000    0.000    0.000 {method 'get' of 'dict' objects}
       48    0.000    0.000    0.000    0.000 {built-in method builtins.min}
      114    0.000    0.000    0.000    0.000 {method 'lower' of 'str' objects}
        6    0.000    0.000    0.000    0.000 {method 'splitlines' of 'str' objects}
       30    0.000    0.000    0.000    0.000 {method 'startswith' of 'str' objects}
      102    0.000    0.000    0.000    0.000 {built-in method builtins.len}
       54    0.000    0.000    0.000    0.000 metadata.py:320(wrap)
       42    0.000    0.000    0.000    0.000 {built-in method builtins.isinstance}
        6    0.000    0.000    0.000    0.000 {method 'extend' of 'list' objects}
        6    0.000    0.000    0.000    0.000 {method 'items' of 'collections.OrderedDict' objects}
        6    0.000    0.000    0.000    0.000 {method 'disable' of '_lsprof.Profiler' objects}

and in the UI there is no noticeable delay when expanding the dataset.

[mvdbeek]

Well, that's a nice set of unrelated errors ... really need to clean up those failing tests. But looks like none of these are related to this PR.