Delayed task is never executed if basename is set

[smheidrich]

Description

If I set the "basename" option of a task that has been created via doit.create_after, this task is never executed.

Minimal example to reproduce

Here is a minimal dodo.py file to reproduce the error. You can see from the output to sys.stderr that this is not merely a case of not reporting the task's run, but it actually doesn't run at all.
Note that removing either the "basename" option or the create_after decorator produces the "correct" behaviour; it is only when used together that they cause trouble.

dodo.py:

from doit import create_after
import sys

def say_hello(your_name):
  sys.stderr.write("Hello from {}!\n".format(your_name))

def task_a():
  return {
    "actions": [ (say_hello, [ "a" ] ) ]
  }

@create_after("a")
def task_b():
  return {
    "actions": [ (say_hello, [ "b" ] ) ],
    "basename": "B saying hello"
  }

Expected behaviour

Terminal log:

$ doit
.  a
Hello from a!
.  B saying hello
Hello from b!
$ 

Actual behaviour

Terminal log:

$ doit
.  a
Hello from a!
$ 

System information

• doit version: 0.27.0
• Python version: 3.4.2

[schettino72]

The best bug report I ever got 👍

I forgot to write a note on docs about this... Since the metadata of a delayed task is only created on demand it is currently not possible to set a basename. doit needs to know which task-creator function needs to be execute the get the metadata of the requested task.

What I thought before was to extend the decorator to accept a creates argument, something like

@create_after("a", creates=['B saying hello'])
def task_b():
   ...

[schettino72]

I added a note in docs about this limitation: 7fd9f9a

[smheidrich]

That was fast - thank you!