(cloudwatch): mypy going crazy around types in cdk >= 2.21.0

[kornicameister]

Describe the bug

monitoring/ses_stack.py: note: In member "__init__" of class "SESStack":
monitoring/ses_stack.py:146:19: error: List item 0 has incompatible type "Metric"; expected "IMetric"  [list-item]
monitoring/ses_stack.py:146:19: note: "Metric" is missing following "IMetric" protocol member:
monitoring/ses_stack.py:146:19: note:     warnings
monitoring/ses_stack.py:150:20: error: List item 0 has incompatible type "Metric"; expected "IMetric"  [list-item]
monitoring/ses_stack.py:150:20: note: "Metric" is missing following "IMetric" protocol member:
monitoring/ses_stack.py:150:20: note:     warnings
monitoring/ses_stack.py:157:19: error: List item 0 has incompatible type "Metric"; expected "IMetric"  [list-item]
monitoring/ses_stack.py:157:19: note: "Metric" is missing following "IMetric" protocol member:
monitoring/ses_stack.py:157:19: note:     warnings
monitoring/ses_stack.py:161:20: error: List item 0 has incompatible type "Metric"; expected "IMetric"  [list-item]
monitoring/ses_stack.py:161:20: note: "Metric" is missing following "IMetric" protocol member:
monitoring/ses_stack.py:161:20: note:     warnings
monitoring/ses_stack.py:168:19: error: List item 0 has incompatible type "Metric"; expected "IMetric"  [list-item]
monitoring/ses_stack.py:168:19: note: "Metric" is missing following "IMetric" protocol member:
monitoring/ses_stack.py:168:19: note:     warnings
monitoring/ses_stack.py:172:20: error: List item 0 has incompatible type "Metric"; expected "IMetric"  [list-item]
monitoring/ses_stack.py:172:20: note: "Metric" is missing following "IMetric" protocol member:
monitoring/ses_stack.py:172:20: note:     warnings
monitoring/ses_stack.py: note: In member "widgets" of class "SESStack":
monitoring/ses_stack.py:182:13: error: List item 0 has incompatible type "Row"; expected "IWidget"  [list-item]
monitoring/ses_stack.py:182:13: note: "Row" is missing following "IWidget" protocol member:
monitoring/ses_stack.py:182:13: note:     warnings
monitoring/ses_stack.py:196:13: error: List item 1 has incompatible type "Row"; expected "IWidget"  [list-item]
monitoring/ses_stack.py:196:13: note: "Row" is missing following "IWidget" protocol member:
monitoring/ses_stack.py:196:13: note:     warnings

Expected Behavior

mypy reports no errors as it was doing in cdk==2.20.0

Current Behavior

Without any changes, code that previously checked out correctly, now throws a bunch of errors around types.

Reproduction Steps

1. install latest cdk (2.22.0)
2. install mypy 0.950
3. run mypy over python sources

Possible Solution

🤷

Additional Information/Context

No response

CDK CLI Version

2.22.0

Framework Version

No response

Node.js Version

14.17.5

OS

MacOs BigSur

Language

Python

Language Version

3.10.1

Other information

No response

[gavllew]

The problem here is that #19825 added a warnings property to the IMetric interface, but failed to add it to the Metric class that implements that interface. This is causing mypy to complain about assignments/parameters that should be valid, as it thinks Metric and IMetric are not compatible.

[kornicameister]

@gavllew so the fix is to change type of Metric ti hold warnings? But it doesn't make sense if Metric implements IMetric, right?

[kornicameister]

@gavllew @madeline-k would that #20369 be a proper starting point to fix that?

[gavllew]

@kornicameister Yes, I think that is all that should be necessary.

[kornicameister]

That also pops around cw.Row being not compatible with cw.IWidget :/

[kornicameister]

@madeline-k @gavllew I changed the type of linked PR to ready to review, awaiting feedback.
I will try to find out what's wrong around cw.Row

[github-actions]

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