Display hints when the glue packages are not efficiently configured

[jkronegg]

🤔 What's changed?

When the JavaBackend loads many classes, but only a few steps/hooks, then we log an hint message to improve the situation.
The hint message can suggest (when applicable and by decreasing efficiency):

• to configure the glue package property
• to remove classes from the glue packages
• to make public static inner classes private
• to remove non-public static inner classes from the glue packages

This replaces the WARN message which occurs when the glue property is not configured.

Here is an example:

[INFO]      [java] INFO: Scanning the glue packages took 1163 ms for 3016 classes, but only 1 of them are Cucumber glue items. You could gain about 1163 ms by cleaning the glue package. Some advices (by decreasing efficiency):
[INFO]      [java] 1) By default Cucumber scans the entire classpath for step definitions.
[INFO]      [java] You can restrict this by configuring the glue path.
[INFO]      [java] 
[INFO]      [java] Examples:
[INFO]      [java]  - @CucumberOptions(glue = "com.example.application")
[INFO]      [java]  - @ConfigurationParameter(key = GLUE_PROPERTY_NAME, value = "com.example.application")
[INFO]      [java]  - src/test/resources/junit-platform.properties   cucumber.glue=com.example.application
[INFO]      [java]  - src/test/resources/cucumber.properties         cucumber.glue=com.example.application
[INFO]      [java] 
[INFO]      [java] 2) remove the classes that do not contain cucumber step/hooks/injectors, e.g.:
[INFO]      [java] net.bytebuddy.implementation.EqualsMethod$ValueComparator$1
[INFO]      [java] net.bytebuddy.implementation.bytecode.assign.Assigner$1
[INFO]      [java] net.bytebuddy.implementation.bytecode.Removal$1
[INFO]      [java] net.bytebuddy.dynamic.loading.ByteArrayClassLoader$PersistenceHandler$1
[INFO]      [java] net.bytebuddy.description.annotation.AnnotationValue$ForConstant$PropertyDelegate$ForNonArrayType$4
[INFO]      [java] net.bytebuddy.implementation.bytecode.member.Invokedynamic
[INFO]      [java] net.bytebuddy.build.Plugin$Engine$ErrorHandler$Failing$2
[INFO]      [java] net.bytebuddy.matcher.AccessibilityMatcher
[INFO]      [java] net.bytebuddy.utility.dispatcher.JavaDispatcher$1
[INFO]      [java] net.bytebuddy.implementation.HashCodeMethod$ValueTransformer$4
[INFO]      [java] 
[INFO]      [java] 3) for classes that contain steps/hooks/injectors, change public static inner classes to private (or remove them from the glue package), e.g.:
[INFO]      [java] net.bytebuddy.agent.ByteBuddyAgent$ProcessProvider
[INFO]      [java] net.bytebuddy.implementation.attribute.FieldAttributeAppender$ForInstrumentedField
[INFO]      [java] net.bytebuddy.description.method.ParameterDescription$InGenericShape
[INFO]      [java] net.bytebuddy.pool.TypePool$Default$LazyTypeDescription$GenericTypeToken$Resolution
[INFO]      [java] net.bytebuddy.asm.AsmVisitorWrapper$ForDeclaredMethods
[INFO]      [java] net.bytebuddy.asm.Advice$OffsetMapping$Sort
[INFO]      [java] net.bytebuddy.description.type.TypeDescription$Generic$Visitor$Validator
[INFO]      [java] net.bytebuddy.implementation.Implementation$Context$Default
[INFO]      [java] net.bytebuddy.asm.Advice$BootstrapArgumentResolver$ForDefaultValues
[INFO]      [java] net.bytebuddy.asm.MemberSubstitution$Substitution$Chain$Step$ForDelegation$BootstrapArgumentResolver$Factory
[INFO]      [java] 
[INFO]      [java] 4) for classes that contain steps/hooks/injectors, remove non-public static inner classes from the glue package, e.g.:
[INFO]      [java] net.bytebuddy.agent.builder.AgentBuilder$Default$Transforming
[INFO]      [java] net.bytebuddy.agent.builder.AgentBuilder$RedefinitionStrategy$Collector$ForRetransformation
[INFO]      [java] net.bytebuddy.pool.TypePool$Default$GenericTypeExtractor$ForSignature$OfRecordComponent
[INFO]      [java] net.bytebuddy.asm.Advice$Dispatcher$RelocationHandler$ForType$Bound
[INFO]      [java] net.bytebuddy.implementation.bytecode.constant.MethodConstant$CanCacheIllegal
[INFO]      [java] net.bytebuddy.pool.TypePool$Default$WithLazyResolution$LazyResolution
[INFO]      [java] net.bytebuddy.agent.builder.AgentBuilder$Default$Redefining
[INFO]      [java] net.bytebuddy.description.type.TypeDescription$Generic$AnnotationReader$ForOwnerType$AnnotatedType
[INFO]      [java] net.bytebuddy.implementation.bytecode.constant.MethodConstant$PrivilegedLookup
[INFO]      [java] net.bytebuddy.pool.TypePool$Default$LazyTypeDescription$GenericTypeToken$ForGenericArray$LazyGenericArray

The behavior can be controlled through properties:

• cucumber.glue.hint.enabled: determine if the hint is displayed or not (by default true)
• cucumber.glue.hint.threshold: the expected gain threshold in milliseconds (by default 100)

⚡️ What's your motivation?

Helping the developer to configure Cucumber helps to get good performances.
Contributes to #3141.

🏷️ What kind of change is this?

• ⚡ New feature (non-breaking change which adds new behaviour)

♻️ Anything particular you want feedback on?

Up to 10 classes are displayed in each hint category: the idea is to give an idea to the developer, not to be exhaustive.
The log message is displayed only if the expected gain is higher than 100 ms.

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

[jkronegg]

@mpkorstanje any suggestion on how to solve the semver issue ?

[mpkorstanje]

For now don't worry about it.

[mpkorstanje]

Looks good.

1. Please reduce the incidental details in loadGlue. At a high level should read something like:

if options.isGlueHintEnabled():
    if glueMetrics.expectedGains() > options.getGlueHintThreshold():
        log.info(glueMetrics.performanceHintMessage())

A separate class might be needed to track the metrics and information. But that is okay.

2. The changes to BackendProviderService are breaking. But we can provide the Options by extracting a request object from loadGlue and provide the options there. This would dovetail nicely into #3120. So for now just keep BackendProviderService as is.