[Core] Support multiple doc strings types with same content type (#2343)

[PostelnicuGeorge]

Is your pull request related to a problem? Please describe.
It's the implementation to: #2343

Describe the solution you have implemented
With this implementation is now possible to have DocStrings of default type ("") or a particular contentType like "application/json" to have multiple DocStringTypes (different return types). This gives leverage for users to take full advantage of Jackson ObjectMapper conversions.
Tests were implemented and updated to cover the new situations where it should be allowed to have multiple DocStringTypes per same contentType, this creates much more concise transformers but doesn't allow any more ambiguity around Object as a return type.

[mpkorstanje]

But given that I saw that the java8 project is marked for deprecation I'm awaiting further details on how to deal with this one.

We're planning for deprecation but the project hasn't been deprecated yet - due to a lack of replacement. Until it is removed cucumber-java8 should remain functioning in the same way as cucumber-java.

[PostelnicuGeorge]

But given that I saw that the java8 project is marked for deprecation I'm awaiting further details on how to deal with this one.

We're planning for deprecation but the project hasn't been deprecated yet - due to a lack of replacement. Until it is removed cucumber-java8 should remain functioning in the same way as cucumber-java.

Got it, will investigate that method and see if I manage to make it return the actual GenericReturnType of DocStringType lambdas.

[PostelnicuGeorge]

Fixed the "type erasure" issue, all test pass, I'm able to do a "clean install" at the project level.

[mpkorstanje]

Heya, looks really good!

I've pushed some changes to resolve some of nitpicks I had with the DocStringTypeRegistry and DocStringTypeRegistryDocStringConverter. By making docStringTypeRegistry.lookup return a list it is possible to handle all error cases at once.

I've got some questions about the other changes.

[mpkorstanje]

Btw, don't worry about force pushing. The default is squash merge so we don't have to keep branches clean.

[codecov]

Codecov Report

Merging #2421 (8f9f092) into main (5598e34) will increase coverage by 0.05%.
The diff coverage is 100.00%.

❗ Current head 8f9f092 differs from pull request most recent head 1bcc7b9. Consider uploading reports for the commit 1bcc7b9 to get more accurate results

@@             Coverage Diff              @@
##               main    #2421      +/-   ##
============================================
+ Coverage     83.61%   83.66%   +0.05%     
- Complexity     2634     2646      +12     
============================================
  Files           317      317              
  Lines          9312     9331      +19     
  Branches        905      906       +1     
============================================
+ Hits           7786     7807      +21     
  Misses         1191     1191              
+ Partials        335      333       -2     

Impacted Files	Coverage Δ
...o/cucumber/java8/Java8DocStringTypeDefinition.java	60.00% <ø> (ø)
...a8/src/main/java/io/cucumber/java8/LambdaGlue.java	82.63% <ø> (ø)
...a/io/cucumber/docstring/DocStringTypeRegistry.java	100.00% <100.00%> (ø)
...tring/DocStringTypeRegistryDocStringConverter.java	100.00% <100.00%> (ø)
.../io/cucumber/java/JavaDocStringTypeDefinition.java	100.00% <100.00%> (+9.09%)	⬆️

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[PostelnicuGeorge]

I have added a test to check that if we use the same parameter type like List of Grocery in a step definition, we're able to use interchangeably that a DocString or DataTable can be used that convert to that particular type. Is there a better place to put this kind of test?
io.cucumber.core.stepexpression.StepExpressionFactoryTest#docstring_and_datatable_match_same_step_definition

[mpkorstanje]

I'd say that StepExpressionFactoryTest is the right place for that test. It's where both converters come together.

Now all that is left now is to add an example to the documentation to illustrate this usecase.

https://github.com/cucumber/cucumber-jvm/tree/main/java#docstring-type

I think one one example where two json doc strings are converted to different objects would be sufficient.

[PostelnicuGeorge]

I have added the example, is there something else remaining? What's the process now going further?
Also is there any PR / Change Request that you see fit I can handle, I have some spare time at the end of this year.

[mpkorstanje]

I'll have to find the time to give it another review and then it will presumably be merged and released.

All the issues tagged with help wanted should be one you could pick up.