next_ds changed to proxy and it cannot be used in ds_add macro function

[ShaharPotash1]

Apache Airflow version

2.2.0 (latest released)

Operating System

Ubuntu

Versions of Apache Airflow Providers

No response

Deployment

Docker-Compose

Deployment details

No response

What happened

Tried to use this this code:
some_variable='{{macros.ds_format(macros.ds_add(next_ds, ' '(ti.start_date - ti.execution_date).days), ' '"%Y-%m-%d", "%Y-%m-%d 21:00:00")}}')
but got this error:
strptime() argument 1 must be str, not Proxy
because the next_ds variable changed to proxy.

What you expected to happen

No response

How to reproduce

No response

Anything else

No response

Are you willing to submit PR?

• Yes I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct

[boring-cyborg]

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[ShaharPotash1]

@potiuk

[uranusjr]

I think we need to explicitly cast inputs with str() in airflow/macros/__init__.py. For example:

def ds_add(ds, days):
    ds = datetime.strptime(str(ds), '%Y-%m-%d')  # Note the extra str() call.
    ...

Fancy a pull request fixing this? Some tests to make sure this doesn't regress would probably be needed.