google / google/python-fire

**kwargs unexpectedly parses flags for later chained method

Open
#659 1 comment 0 reactions 0 assignees View on GitHub
Dominant language
Python
Stars
28.2k
Forks
1.5k
PR merge metrics
No merged PRs in 30d

Description

Suppose we have the following program

```python
from dataclasses import dataclass

@dataclass
class MyClass:
x: int

def transform(self, **kwargs):
return MyClass(self.x * kwargs.get("multiplier", 2))

def do_something(self, msg):
print(f"{msg}: {self.x}")

my_obj = MyClass(3)
```

And we call it with `python -m fire my_module my_obj transform --multiplier=3 do_something --msg="test"`, then the `--msg` is parsed when calling `transform` into the `kwargs` dict. Then it errors saying `--msg` is missing. Can we instead support parsing flags before the next chained method call? The kwargs is useful for example, to transform the object in ways that only implementation classes know what to do.

My current workarounds are (1) pass msg as positional arg to `do_something`, (2) have `do_something` take `**kwargs` and call `transform` within it. Neither is ideal as (1) would surprise anyone who uses my code and (2) adds extra plumbing that could be avoided.

Contributor guide

Open the contributing guide

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.