result_callback in Click 8.x not working anymore?

Question

I spend almost my whole day to troubleshoot one of my scripts giving me a big headache. It ended up with the problem, that is seems that in version 8.x the result_callback isn't executed anymore in my case.

Sample:

@click.command(cls=PluginCommands) # PluginCommands is inherited from click.MultiCommand)
@click.pass_context
def foo(ctx):
   pass

@foo.command('bar')
def bar(ctx):
   do_stuff()

foo.result_callback = some_mailing_function

This used to work pretty well with version 7.1.2, but not with the accidentally installed 8.1.3. It seems that the registered function in result_callback is never executed.

Has someone else came across this problem?

Many thanks in advance, regards, Thomas

Answer 1

result_callback may be used in two ways:

1. It can be provided as an argument by the initialization of the MultiCommand class or
2. It can be used as a decorator later.

If we use the second approach, your code should be similar to this:

@click.command(cls=PluginCommands) # PluginCommands is inherited from click.MultiCommand)
@click.pass_context
def foo(ctx):
   pass

@foo.result_callback()
def some_mailing_function():
    pass

@foo.command('bar')
def bar(ctx):
   do_stuff()