return shallow copy in build_const_args (#1103)

Co-authored-by: Matthew Avaylon <[email protected]>

CHANGELOG.md

@@ -12,6 +12,7 @@
 dataset based on the shape of the dataset data and the dimension names in the spec for the data type. This attribute
 is available on build (during the write process), but not on read of a dataset from a file. @rly [#1081](https://github.com/hdmf-dev/hdmf/pull/1081)
 - Speed up loading namespaces by skipping register_type when already registered. @magland [#1102](https://github.com/hdmf-dev/hdmf/pull/1102)
+- Speed up namespace loading: return a shallow copy rather than a deep copy in build_const_args. @magland [#1103](https://github.com/hdmf-dev/hdmf/pull/1103)
 
 ## HDMF 3.14.2 (July 7, 2024)
 

src/hdmf/spec/spec.py

@@ -1,7 +1,6 @@
 import re
 from abc import ABCMeta
 from collections import OrderedDict
-from copy import deepcopy
 from warnings import warn
 
 from ..utils import docval, getargs, popargs, get_docval
@@ -84,7 +83,7 @@ class ConstructableDict(dict, metaclass=ABCMeta):
     def build_const_args(cls, spec_dict):
         ''' Build constructor arguments for this ConstructableDict class from a dictionary '''
         # main use cases are when spec_dict is a ConstructableDict or a spec dict read from a file
-        return deepcopy(spec_dict)
+        return spec_dict.copy()
 
     @classmethod
     def build_spec(cls, spec_dict):