[Bug] String interpolation in instantiate is broken in hydra 1.0.2

[cmnrd]

🐛 Bug

Description

String interpolation does not work when the config node is used in instantiate().

Checklist

• I checked on the latest version of Hydra
• I created a minimal repro

To reproduce

** Minimal Code/Config snippet to reproduce **

demo.py:

import hydra

class Test:

    def __init__(self, string):
        print("init: " + string)

@hydra.main(config_path='conf', config_name='test')
def main(cfg):
    print("main: " + cfg['test']['string'])
    hydra.utils.instantiate(cfg['test'])

if __name__ == "__main__":
    main()

conf/test.yaml:

# @package _global_
foo: 42
test:
  _target_: demo.Test
  string: "21 * 2 = ${foo}"
conf/test.yaml (END)

** Stack trace/error message **

No error is produced, but the output printed by the code above is erroneous when using hydra 1.0.2 or the latest master.

main: 21 * 2 = 42
init: 21 * 2 = ${foo}

When referencing test.string directly from the python code, foo gets resolved correctly to 42 (first line). However, when passing the interpolated string via instantiate() to the class Test, ${foo} does not get resolved (second line).

Expected Behavior

The expected output is:

main: 21 * 2 = 42
init: 21 * 2 = 42

This output was produced with hydra 1.0.1.

System information

• Hydra Version : 1.0.2
• Python version : 3.8.5
• Virtual environment type and version : virtualenv 20.0.23
• Operating system : Linux (Manjaro)

Additional context

Add any other context about the problem here.

[omry]

Thanks for reporting, is this a regression in 1.0.2? (does it work with 1.0.1)?
I saw you created a PR and closed, what's going on with that?

[cmnrd]

Yes, it is a regression in 1.0.2. It works perfectly in 1.0.1. The 'Expected Behavior' above is the output from hydra 1.0.1.

I have no idea about this PR. It was opened and closed by someone else (@mipo57).

[omry]

Yes, it is a regression in 1.0.2. It works perfectly in 1.0.1. The 'Expected Behavior' above is the output from hydra 1.0.1.

Thanks.

I have no idea about this PR. It was opened and closed by someone else (@mipo57).

Interesting :)

[omry]

There was a nasty bug in the tests that allowed this regression to happen, sorry about it.

[omry]

@cmnrd , can you confirm that master works for you?

[cmnrd]

Yes, it works. Thanks!