Dict with length 1 loses its key after self.load() about gokart HOT 2 OPEN

@naokimaejima @nersonu

Thank you for raising interesting issue.

Is it conceivable to eliminate the L235-236 and L265-266 process?

I agree with your idea.

As @naokimaejima mentioned, this behavior is caused because of following code.

if target is None and isinstance(data, dict) and len(data) == 1: 
     return list(data.values())[0] 

This is implemented to make loading easier when using default requires().

class A(gokart.TaskOnKart):
    task = gokart.TaskInstanceParameter()

    def run(self):
        a = self.load()

In the above example, self.load() is possible because of the default requires() inherited from TaskOnKart.
https://github.com/m3dev/gokart/blob/master/gokart/task.py#L92

The default requires() will return a dict of gokart.TaskInstanceParameter().
Therefore, when single task is declared, loading it should be done as list(self.load())[0].
When single task is declared, the mentioned code snippet will work and return single task instead the dict which will allow loading with self.load().

However, I think the benefit of this implementation is very limited and disadvantage caused by confusion is more significant.
So I think removing this implementation is good idea.

PR is welcome!

from gokart.

@hirosassa @Hi-king
When parsing JSON, it is often the case that the dict root key has a length of 1.
It seems to me that if you want to include a process to distinguish between a dict that is the result of a task and a dict specified in requires, you would have to change luigi.
Is it conceivable to eliminate the L235-236 and L265-266 process?

from gokart.