RegEx matching and binding problems with optional parameters

[drosenba]

This used to work in SpecFlow v3 (with SpecFlow+ Runner), but now trying ReqnRoll (with MSTest) and there are RegEx matching and binding problems.

The C# code. There are "optional" parameters (capturing groups)

    [Given(@"I\s*(test)\s+'([^']+)'\s+as\s+'([^']+)'(?:\s+(plus|minus)\s+'([^']+)')?")]
    public void RememberTest(string keyword, string label, string nameOrValue2, string deviateTypeKeyword, string nameOrValue3)
    { ... }

My first example Gherkin step

Given I test 'variable' as 'nameOrValue1-A'

The step is matched, but the binding is confused.
-> binding error: Parameter count mismatch! The binding method '...MySteps.RememberTest(String, String, String, String)' should have 2 parameters

My 2nd example Gherkin step

Given I test 'variable' as 'nameOrValue1-A' plus 'nameOrValue2-B'

The step is not matched

Assert.Inconclusive failed. No matching step definition found for one or more steps.

The suggestion is
[Given("I test {string} as {string} plus {string}")]
public void GivenITestAsPlus(string variable0, string p1, string p2)

In my external C# test program, I've confimed the regex matching / groups

DoMatch: I test 'variable' as 'nameOrValue1-A'
Matched:
Full Match: I test 'variable' as 'nameOrValue1-A'
Group 1 - keyword : 'test'
Group 2 - variable : 'variable'
Group 3 - nameOrValue1 : 'nameOrValue1-A'
Group 4 - deviationKeyword : ''
Group 5 - nameOrValue2 : ''

DoMatch: I test 'variable' as 'nameOrValue1-A' plus 'nameOrValue2-B'
Matched:
Full Match: I test 'variable' as 'nameOrValue1-A' plus 'nameOrValue2-B'
Group 1 - keyword : 'test'
Group 2 - variable : 'variable'
Group 3 - nameOrValue1 : 'nameOrValue1-A'
Group 4 - deviationKeyword : 'plus'
Group 5 - nameOrValue2 : 'nameOrValue2-B'

I've also tried " = null" for the optional parameters, and get the same errors.
public void RememberTest(string label, string nameOrValue2, string deviateTypeKeyword = null, string nameOrValue3 = null)

I've also tried removing initial capture group "(test)"
[Given(@"I\s*test\s+'([^']+)'\s+as\s+'([^']+)'(?:\s+(plus|minus)\s+'([^']+)')?")]
public void RememberTest(string label, string nameOrValue2, string deviateTypeKeyword, string nameOrValue3)

[ajeckmans]

You are running into an undocumented feature that has stopped working in the unreleased v4 version of specflow which was used as the basis for ReqnRoll.
See also #181

[gasparnagy]

I have found the related things, so posting it here as well:

See discussion at #238. Based on that @olegKoshmeliuk has made the interface to override the behavior per-project (to support legacy / migration cases).

Could you please try if overriding that integrace and implementing the more SpecFlow-compatibility handling way of regex groups would work for you? If yes, we could add it as a sample solution to https://docs.reqnroll.net/latest/guides/how-to-configure-cucumber-expression-behavior.html

[gasparnagy]

@olegKoshmeliuk do you maybe have an example in-project plugin that you can share as an example?