Send build failure notifications to build definition .yml file synthetic sibling CODEOWNERS owners, instead of the owners of the .yml file itself.

[konrad-jamrozik]

This PR implements capability as described in:

• Add support for sending build failure notifications to different CODEOWNERS owners than the origin build definition owners. #5181

plus does a little bit of related message output changes and code refactoring.

Copy-pasting here the relevant paragraph for convenience:

We will make the notification-configuration tool search for owners not of the pipeline definition file it originated from (e.g. /foo/ci.yml), but a made-up sibling file named e.g. PipelineOwner, e.g. /foo/PipelineOwner. This way if there is a CODEOWNERS path that matches to /foo/ci.yml it is not going to be used to determine where to route build failure notifications, but as a CODEOWNERS path that matches /foo/PipelineOwner, e.g. /foo/, will. You can find the details of this approach, and preceding discussion, here:

• Remove CODEOWNERS rules /**/ci.yml and /**/tests.yml azure-sdk-for-net#33595 (comment)

Testing done

I did some manual testing with C# snippets to confirm the introduced method GetSiblingFilePath behaves as expected. All other changes are done via automated IDE refactorings so should be safe.

Expected behavior change

Once this change goes in effect via PR similar to this one:

• Update Azure.Sdk.Tools.NotificationConfiguration in globals.yml from 20230108.1 to 20230119.1 #5177

I expect there will be some changes to whom the build failure notifications are routed.

I reviewed the CODEOWNERS files targeted by the automation - build-failure-notification-subscriptions pipeline. Below I list the files and cases where owners who receive build failure notifications will change.

File	Expected changes
https://github.com/Azure/azure-dev/blob/main/.github/CODEOWNERS	None
https://github.com/Azure/azure-sdk-for-c/blob/main/.github/CODEOWNERS	None
https://github.com/Azure/azure-sdk-for-cpp/blob/main/.github/CODEOWNERS	None
https://github.com/Azure/azure-sdk-for-go/blob/main/.github/CODEOWNERS	None
https://github.com/Azure/azure-sdk-for-java/blob/main/.github/CODEOWNERS	aggregate-reports.yml, build
https://github.com/Azure/azure-sdk-for-js/blob/main/.github/CODEOWNERS	Over 100 .yml files
https://github.com/Azure/azure-sdk-for-net/blob/main/.github/CODEOWNERS	4 .yml files
https://github.com/Azure/azure-sdk-for-python/blob/main/.github/CODEOWNERS	7 .yml files

Most likely we want to modify the CODEOWNERS files before applying the effects of this PR, to keep the recipients of build failure notifications unchanged. This can be achieved by adding relevant paths to the CODEOWNERS file.

E.g. a block like:

# PRLabel: %Mgmt
/sdk/appplatform/arm-appplatform @qiaozha @dw511214992 @MaryGao
/sdk/appplatform/ci.mgmt.yml @qiaozha @dw511214992 @MaryGao

Can be replaced with:

/sdk/appplatform/ @qiaozha @dw511214992 @MaryGao
# PRLabel: %Mgmt
/sdk/appplatform/arm-appplatform @qiaozha @dw511214992 @MaryGao
/sdk/appplatform/ci.mgmt.yml @qiaozha @dw511214992 @MaryGao

Additional design notes

Currently I assume the proposed PipelineOwnerSyntheticFileName is not present in the repository nor in CODEOWNERS file. But we might actually want to consider adding this file path to CODEOWNERS a valid approach, to fine-tune who gets the build notifications. Then the example above would become, for example:

# PRLabel: %Mgmt
/sdk/appplatform/arm-appplatform @qiaozha @dw511214992 @MaryGao
/sdk/appplatform/__PipelineOwner__ @qiaozha @dw511214992 @MaryGao
/sdk/appplatform/ci.mgmt.yml @qiaozha @dw511214992 @MaryGao

However, in such case, we would need to add special case that such file should not actually exist, in our validation spec:

• Implement CODEOWNERS file changes validation (gating), with baselining #4859 (comment)

[konrad-jamrozik]

@weshaggard I need your input before I can proceed with this PR. Please see the description, sections "Expected behavior change" and "Additional design notes".

Should I go ahead with adjusting all the language repo CODEOWNERS files to ensure this PR doesn't change any recipients of build failure notifications? If so, which approach would you prefer? I like the approach that adds the synthetic file name to CODEOWNERS just above the .yml file, like: /sdk/appplatform/__PipelineOwner__.

[weshaggard]

As I mentioned in the original PR lets not go after this right now. @benbp will look into other workflows for monitoring all the yml files in the repo.

[konrad-jamrozik]

Closing this PR per Wes' comment above. Instead, I submitted a PR that incorporates refactorings made in this PR, and more:

• Extract Contacts class + related refactorings to NotificationConfigurator class. #5214