From d249fbbba9d34b89cd21885c065542f3604d7752 Mon Sep 17 00:00:00 2001
From: Kirill Gevorkyan <26010098+kgevorkyan@users.noreply.github.com>
Date: Mon, 8 Nov 2021 19:46:59 +0700
Subject: [PATCH] Fix NPE in GENERIC_VARIABLE_WRONG_DECLARATION (#1098)

### What's done:
* Fix bug - allow cases with wild card types
* Add tests
---
 .../VariableGenericTypeDeclarationRule.kt     |  7 ++-
 ...iableGenericTypeDeclarationRuleWarnTest.kt | 54 +++++++++++++++++++
 2 files changed, 60 insertions(+), 1 deletion(-)

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 }) {
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`() {