CodeBuilder: do not rely on type of input_plugin_name

The `CodeBuilder` could receive the `input_plugin_name` keyword argument
as an `EntryPoint` from the `verdi code setup/duplicate` commands, so it
included a switch to get the entry point name from it.

Due to a bug in setuptools, the type of the `EntryPoint` can change
under certain circumstances and so the `isinstance` check on the entry
point does not hit. This causes the `EntryPoint` to be passed to the
`Code.set_input_plugin_name` method, which does not check the type and
casts the argument to `str`. However, the `__str__` of `EntryPoint` does
not return just the name, but a more verbose representation. This will
cause the `Code` to be unusable.

The conversion of the `EntryPoint` to its name in the `CodeBuilder is
removed and instead the CLI commands are responsible for passing the
string entry point name.

Ideally, `Code.set_input_plugin_name` is updated to only accept `str`
arguments and remove the cast. But this would be a breaking change and
so is not done for now.

aiida/cmdline/commands/cmd_code.py

@@ -89,6 +89,9 @@ def setup_code(ctx, non_interactive, **kwargs):
     else:
         kwargs['code_type'] = CodeBuilder.CodeType.STORE_AND_UPLOAD
 
+    # Convert entry point to its name
+    kwargs['input_plugin'] = kwargs['input_plugin'].name
+
     code_builder = CodeBuilder(**kwargs)
 
     try:
@@ -160,6 +163,9 @@ def code_duplicate(ctx, code, non_interactive, **kwargs):
     if kwargs.pop('hide_original'):
         code.hide()
 
+    # Convert entry point to its name
+    kwargs['input_plugin'] = kwargs['input_plugin'].name
+
     code_builder = ctx.code_builder
     for key, value in kwargs.items():
         setattr(code_builder, key, value)

aiida/orm/utils/builders/code.py

@@ -11,8 +11,6 @@
 import enum
 import os
 
-import importlib_metadata
-
 from aiida.cmdline.utils.decorators import with_dbenv
 from aiida.common.utils import ErrorAccumulator
 
@@ -155,9 +153,6 @@ def _set_code_attr(self, key, value):
 
         Checks compatibility with other code attributes.
         """
-        if key == 'input_plugin' and isinstance(value, importlib_metadata.EntryPoint):
-            value = value.name
-
         if key == 'description' and value is None:
             value = ''