Bugfix. NPE in TrivialPropertyAccessors rule

diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/TrivialPropertyAccessors.kt

@@ -32,6 +32,7 @@ class TrivialPropertyAccessors(private val configRules: List<RulesConfig>) : Rul
 
     companion object {
         private val EXCESS_CHILDREN_TYPES = listOf(LBRACE, RBRACE, WHITE_SPACE, EOL_COMMENT, BLOCK_COMMENT)
+        private const val ONE_CHILD_IN_ARRAY = 1
     }
 
     override fun visit(node: ASTNode,
@@ -56,12 +57,12 @@ class TrivialPropertyAccessors(private val configRules: List<RulesConfig>) : Rul
     @Suppress("UnsafeCallOnNullableType")
     private fun handleSetAccessor(node: ASTNode) {
         val valueParamName = node
-                .getFirstChildWithType(VALUE_PARAMETER_LIST)!!
-                .firstChildNode
-                .getIdentifierName()!!
-                .text
+                .getFirstChildWithType(VALUE_PARAMETER_LIST)
+                ?.firstChildNode
+                ?.getIdentifierName()
+                ?.text
 
-        if (node.hasChildOfType(BLOCK)) {
+        if (node.hasChildOfType(BLOCK) && !valueParamName.isNullOrEmpty()) {
             val block = node.getFirstChildWithType(BLOCK)!!
 
             val blockChildren = block.getChildren(null).filter { it.elementType !in EXCESS_CHILDREN_TYPES }
@@ -82,6 +83,8 @@ class TrivialPropertyAccessors(private val configRules: List<RulesConfig>) : Rul
         val references = node.findAllNodesWithSpecificType(REFERENCE_EXPRESSION)
         if (references.singleOrNull()?.text == "field") {
             raiseWarning(node)
+        } else if (node.getChildren(null).size == ONE_CHILD_IN_ARRAY) {
+            raiseWarning(node)
         }
     }
 

diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter6/TrivialPropertyAccessorsFixTest.kt

@@ -1,6 +1,5 @@
 package org.cqfn.diktat.ruleset.chapter6
 
-import generated.WarningNames
 import generated.WarningNames.TRIVIAL_ACCESSORS_ARE_NOT_RECOMMENDED
 import org.cqfn.diktat.util.FixTestBase
 import org.cqfn.diktat.ruleset.rules.TrivialPropertyAccessors

diktat-rules/src/test/kotlin/org/cqfn/diktat/ruleset/chapter6/TrivialPropertyAccessorsWarnTest.kt

@@ -61,4 +61,31 @@ class TrivialPropertyAccessorsWarnTest : LintTestBase(::TrivialPropertyAccessors
                 """.trimMargin()
         )
     }
+
+    @Test
+    @Tag(TRIVIAL_ACCESSORS_ARE_NOT_RECOMMENDED)
+    fun `should not trigger on private setter`() {
+        lintMethod(
+                """
+                    |class Test {
+                    |   var testName: String? = null
+                    |       private set
+                    |}
+                """.trimMargin()
+        )
+    }
+
+    @Test
+    @Tag(TRIVIAL_ACCESSORS_ARE_NOT_RECOMMENDED)
+    fun `should trigger on getter without braces`() {
+        lintMethod(
+                """
+                    |class Test {
+                    |   val testName = 0
+                    |       get
+                    |}
+                """.trimMargin(),
+                LintError(3, 8, ruleId, "${Warnings.TRIVIAL_ACCESSORS_ARE_NOT_RECOMMENDED.warnText()} get", true)
+        )
+    }
 }

diktat-rules/src/test/resources/test/chapter6/properties/TrivialPropertyAccessorsExpected.kt

@@ -8,4 +8,9 @@ class Some {
     var propNotChange: Int = 7
         get() { return someCoolLogic(field) }
         set(value) { anotherCoolLogic(value) }
+
+    var testName: String? = null
+        private set
+
+    val x = 0
 }

diktat-rules/src/test/resources/test/chapter6/properties/TrivialPropertyAccessorsTest.kt

@@ -11,4 +11,10 @@ class Some {
     var propNotChange: Int = 7
         get() { return someCoolLogic(field) }
         set(value) { anotherCoolLogic(value) }
+
+    var testName: String? = null
+        private set
+
+    val x = 0
+        get
 }