Repository: cqfn/diKTat (kotlin)

Issue:
Null pointer exception at: GENERIC_VARIABLE_WRONG_DECLARATION
```
package io.reflekt.plugin.scripting

import io.reflekt.plugin.analysis.models.Import
import java.io.File
import kotlin.reflect.KClass
import kotlin.script.experimental.api.*
import kotlin.script.experimental.host.toScriptSource
import kotlin.script.experimental.jvm.jvm
import kotlin.script.experimental.jvm.updateClasspath
import kotlin.script.experimental.jvmhost.BasicJvmScriptingHost

class KotlinScript(
    code: String,
    imports: List<Import> = emptyList(),
    properties: List<Pair<String, KClass<*>>> = emptyList(),
    classpath: List<File> = emptyList()
) {
    private val argumentNames = properties.map { it.first }
    private val source = (imports.joinToString(separator = System.lineSeparator(), postfix = System.lineSeparator()) { it.text } + code).toScriptSource()
    private val compilationConfiguration = ScriptCompilationConfiguration {
        jvm {
            updateClasspath(classpath)
        }
        providedProperties(*properties.toTypedArray())
    }

    fun eval(arguments: List<*> = emptyList<Any>()): Any? =
        (execute(arguments).value.returnValue as ResultValue.Value).value

    fun run(arguments: List<*> = emptyList<Any>()) {
        execute(arguments)
    }

    private fun execute(arguments: List<*>): ResultWithDiagnostics.Success<EvaluationResult> {
        val evaluationConfiguration = ScriptEvaluationConfiguration {
            providedProperties(*argumentNames.zip(arguments).toTypedArray())
        }
        val result = BasicJvmScriptingHost().eval(
            source, compilationConfiguration, evaluationConfiguration
        )
        if (result !is ResultWithDiagnostics.Success) {
            throw RuntimeException("Failed to evaluate script:\n${result.reports.map { it.render(withStackTrace = true)} }}")
        }
        return result
    }
}
```

Null pointer exception is thrown:
```
[ERROR] 2021-11-07 13:04:25 Internal error has occurred in rule [variable-generic-type]. Please make an issue on this bug at https://github.com/cqfn/diKTat/.
                       As a workaround you can disable these inspections in yml config: <[GENERIC_VARIABLE_WRONG_DECLARATION]>.
                       Root cause of the problem is in [/mnt/d/reflekt/reflekt-plugin/src/main/kotlin/io/reflekt/plugin/scripting/KotlinScript.kt] file.
java.lang.NullPointerException
        at org.cqfn.diktat.ruleset.rules.chapter4.VariableGenericTypeDeclarationRule.handleProperty(VariableGenericTypeDeclarationRule.kt:59)
        at org.cqfn.diktat.ruleset.rules.chapter4.VariableGenericTypeDeclarationRule.logic(VariableGenericTypeDeclarationRule.kt:30)
        at org.cqfn.diktat.ruleset.rules.DiktatRule.visit(DiktatRule.kt:50)
        at com.pinterest.ktlint.core.KtLint$lint$1.invoke(KtLint.kt:81)
        at com.pinterest.ktlint.core.KtLint$lint$1.invoke(KtLint.kt:23)
        at com.pinterest.ktlint.core.KtLint$visitor$2$1.invoke(KtLint.kt:206)
        at com.pinterest.ktlint.core.KtLint$visitor$2$1.invoke(KtLint.kt:23)
        at com.pinterest.ktlint.core.ast.PackageKt.visit(package.kt:224)
        at com.pinterest.ktlint.core.ast.PackageKt.visit(package.kt:225)
        at com.pinterest.ktlint.core.ast.PackageKt.visit(package.kt:225)
        at com.pinterest.ktlint.core.ast.PackageKt.visit(package.kt:225)
        at com.pinterest.ktlint.core.ast.PackageKt.visit(package.kt:225)
        at com.pinterest.ktlint.core.ast.PackageKt.visit(package.kt:225)
        at com.pinterest.ktlint.core.KtLint$visitor$2.invoke(KtLint.kt:204)
        at com.pinterest.ktlint.core.KtLint$visitor$2.invoke(KtLint.kt:23)
        at com.pinterest.ktlint.core.KtLint.lint(KtLint.kt:74)
        at com.pinterest.ktlint.internal.FileUtilsKt.lintFile(FileUtils.kt:51)
        at com.pinterest.ktlint.KtlintCommandLine.process(Main.kt:358)
        at com.pinterest.ktlint.KtlintCommandLine.access$process(Main.kt:116)
        at com.pinterest.ktlint.KtlintCommandLine$lintFiles$2$1.call(Main.kt:257)
        at com.pinterest.ktlint.KtlintCommandLine$lintFiles$2$1.call(Main.kt:116)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Exception in thread "main" java.util.concurrent.ExecutionException: java.lang.Error: Internal error in diktat application
```

Pull request:
### What's done:
* Fix bug - allow cases with wild card types
* Add tests

Patch:
diff --git a/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter4/VariableGenericTypeDeclarationRule.kt b/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter4/VariableGenericTypeDeclarationRule.kt
index 76e508e3f8..b90dde5ff6 100644
--- a/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter4/VariableGenericTypeDeclarationRule.kt
+++ b/diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter4/VariableGenericTypeDeclarationRule.kt
@@ -33,7 +33,7 @@ class VariableGenericTypeDeclarationRule(configRules: List<RulesConfig>) : Dikta
         }
     }
 
-    @Suppress("UnsafeCallOnNullableType")
+    @Suppress("UnsafeCallOnNullableType", "AVOID_NULL_CHECKS")
     private fun handleProperty(node: ASTNode) {
         val callExpr = node.findChildByType(CALL_EXPRESSION)
             ?: node
@@ -54,6 +54,11 @@ class VariableGenericTypeDeclarationRule(configRules: List<RulesConfig>) : Dikta
                 ?.typeArgumentsAsTypes
         }
 
+        // Allow cases with wild card types; `*` interprets as `null` in list of types
+        if (leftSide?.any { it == null } == true) {
+            return
+        }
+
         if (rightSide != null && leftSide != null &&
                 rightSide.size == leftSide.size &&
                 rightSide.zip(leftSide).all { (first, second) -> first.text == second.text }) {


Test patch:
diff --git a/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter4/VariableGenericTypeDeclarationRuleWarnTest.kt b/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter4/VariableGenericTypeDeclarationRuleWarnTest.kt
index ed1757d561..5cc76f3380 100644
--- a/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter4/VariableGenericTypeDeclarationRuleWarnTest.kt
+++ b/diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter4/VariableGenericTypeDeclarationRuleWarnTest.kt
@@ -66,6 +66,34 @@ class VariableGenericTypeDeclarationRuleWarnTest : LintTestBase(::VariableGeneri
         )
     }
 
+    @Test
+    @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
+    fun `property in function as parameter with wildcard type good`() {
+        lintMethod(
+            """
+                    |class SomeClass {
+                    |   private fun someFunc(myVariable: List<*> = emptyList<Int>()) {
+                    |       
+                    |   }
+                    |}
+                """.trimMargin()
+        )
+    }
+
+    @Test
+    @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
+    fun `property in function as parameter with wildcard type good 2`() {
+        lintMethod(
+            """
+                    |class SomeClass {
+                    |   private fun someFunc(myVariable: Map<*, String> = emptyMap<Int, String>()) {
+                    |       
+                    |   }
+                    |}
+                """.trimMargin()
+        )
+    }
+
     @Test
     @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
     fun `property in function as parameter bad`() {
@@ -96,6 +124,20 @@ class VariableGenericTypeDeclarationRuleWarnTest : LintTestBase(::VariableGeneri
         )
     }
 
+    @Test
+    @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
+    fun `property in function with wildcard type good`() {
+        lintMethod(
+            """
+                    |class SomeClass {
+                    |   private fun someFunc() {
+                    |       val myVariable: List<*> = emptyList<Int>()
+                    |   }
+                    |}
+                """.trimMargin()
+        )
+    }
+
     @Test
     @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
     fun `property in function bad`() {
@@ -124,6 +166,18 @@ class VariableGenericTypeDeclarationRuleWarnTest : LintTestBase(::VariableGeneri
         )
     }
 
+    @Test
+    @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
+    fun `property in class with wildcard type good`() {
+        lintMethod(
+            """
+                    |class SomeClass(val myVariable: List<*> = emptyList<Int>()) {
+                    |
+                    |}
+                """.trimMargin()
+        )
+    }
+
     @Test
     @Tag(GENERIC_VARIABLE_WRONG_DECLARATION)
     fun `property in class bad`() {