[5.7] Fix ArgumentExtractor implementation bug (#4287)

[Kyle-Ye]

Fix ArgumentExtractor implementation bug

Motivation:

swift-docc-plugin uses the PackagePlugin API and support generate-documentation action.

If we run

swift package --allow-writing-to-directory ./docs \
    generate-documentation --target SymbolKit --output-path ./docs

It will be fine.
However if we run

swift package --allow-writing-to-directory ./docs \
    generate-documentation --target=SymbolKit --output-path ./docs

It will loop infinitely.

And the core reason seems to be the ArgumentExtractor implementation in PackagePlugin Package.

Modifications:

• Fix the ArgumentExtractor implementation bug
• Add testExtractOption for ArgumentExtractor

Result:

When using --<name>=<value> form to specify the argument, the Plugin will no long loop infinitely.

[Kyle-Ye]

@swift-ci please smoke test

[Kyle-Ye]

@swift-ci please smoke test Linux

[Kyle-Ye]

@swift-ci please smoke test Linux

[Kyle-Ye]

Looks like there is something wrong with “Swift Test Linux Platform(self hosted)”. Cc @abertelrud

[abertelrud]

Here is the error message:

Scripts not permitted to use staticMethod org.codehaus.groovy.runtime.DefaultGroovyMethods getAt java.lang.Object java.lang.String. Administrators can decide whether to approve or reject this signature.

I'll try one more time in case it was transient, otherwise will figure out who to talk to.

[abertelrud]

@swift-ci please smoke test

[abertelrud]

Looks like it failed in the same way. @shahmishal does that error look familiar to you? It isn't one that I have seen before.

[abertelrud]

Both the main and release/5.6 PRs passed, so perhaps this is specific to the 5.7 branch? (e.g. #4289 is the 5.6 branch PR)

[Kyle-Ye]

Here is the error message:

Scripts not permitted to use staticMethod org.codehaus.groovy.runtime.DefaultGroovyMethods getAt java.lang.Object java.lang.String. Administrators can decide whether to approve or reject this signature.

I'll try one more time in case it was transient, otherwise will figure out who to talk to.

This message are occurring in other PR too. (eg. swiftlang/swift-docc#136)
Seems to be a Linux CI bug. Could you help confirm it cc @shahmishal

[Kyle-Ye]

@swift-ci please smoke test Linux

[Kyle-Ye]

The Linux CI issue seems to be solved. Once the Linux test is passed, I think we could land it.