Fixed warning FUNCTION_BOOLEAN_PREFIX on operator fun (#1767)

* Fixed warning `FUNCTION_BOOLEAN_PREFIX` on `operator fun` ### What's done: - fixed warning `FUNCTION_BOOLEAN_PREFIX` on `operator fun`. - added `hasBooleanReturnType()` and `isOperatorFun()` function checks. - added warning test. * Closes #1723
saveourtool · Nov 1, 2023 · 9423c75 · 9423c75
1 parent c28f1a1
commit 9423c75
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Showing 3 changed files with 40 additions and 10 deletions.
diff --git a/...t-rules/src/main/kotlin/com/saveourtool/diktat/ruleset/rules/chapter1/IdentifierNaming.kt b/...t-rules/src/main/kotlin/com/saveourtool/diktat/ruleset/rules/chapter1/IdentifierNaming.kt
@@ -35,7 +35,6 @@ import org.jetbrains.kotlin.KtNodeTypes.REFERENCE_EXPRESSION
 import org.jetbrains.kotlin.KtNodeTypes.TYPE_PARAMETER
 import org.jetbrains.kotlin.KtNodeTypes.TYPE_REFERENCE
 import org.jetbrains.kotlin.KtNodeTypes.VALUE_PARAMETER_LIST
-import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.LeafPsiElement
 import org.jetbrains.kotlin.com.intellij.psi.tree.TokenSet
@@ -403,19 +402,15 @@ class IdentifierNaming(configRules: List<RulesConfig>) : DiktatRule(
             }
         }
 
-        // check for methods that return Boolean
-        val functionReturnType = node.findChildAfter(VALUE_PARAMETER_LIST, TYPE_REFERENCE)?.text
-
         // We don't need to ask subclasses to rename superclass methods
         if (!node.isOverridden()) {
+            // check for methods that return Boolean
             // if function has Boolean return type in 99% of cases it is much better to name it with isXXX or hasXXX prefix
             @Suppress("COLLAPSE_IF_STATEMENTS")
-            if (functionReturnType != null && functionReturnType == PrimitiveType.BOOLEAN.typeName.asString()) {
-                @Suppress("COLLAPSE_IF_STATEMENTS")
-                if (allMethodPrefixes.none { functionName.text.startsWith(it) }) {
-                    // FixMe: add agressive autofix for this
-                    FUNCTION_BOOLEAN_PREFIX.warn(configRules, emitWarn, functionName.text, functionName.startOffset, functionName)
-                }
+
+            if (node.hasBooleanReturnType() && !node.isOperatorFun() && allMethodPrefixes.none { functionName.text.startsWith(it) }) {
+                // FixMe: add agressive autofix for this
+                FUNCTION_BOOLEAN_PREFIX.warn(configRules, emitWarn, functionName.text, functionName.startOffset, functionName)
             }
         }
 

diff --git a/diktat-rules/src/main/kotlin/com/saveourtool/diktat/ruleset/utils/AstNodeUtils.kt b/diktat-rules/src/main/kotlin/com/saveourtool/diktat/ruleset/utils/AstNodeUtils.kt
@@ -35,6 +35,7 @@ import org.jetbrains.kotlin.KtNodeTypes.PARENTHESIZED
 import org.jetbrains.kotlin.KtNodeTypes.REFERENCE_EXPRESSION
 import org.jetbrains.kotlin.KtNodeTypes.TYPE_PARAMETER_LIST
 import org.jetbrains.kotlin.KtNodeTypes.VALUE_PARAMETER_LIST
+import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.openapi.util.Key
 import org.jetbrains.kotlin.com.intellij.psi.PsiElement
@@ -183,6 +184,26 @@ fun ASTNode.isAnonymousFunction(): Boolean {
     return this.getIdentifierName() == null
 }
 
+/**
+ * Checks if the function has boolean return type
+ *
+ * @return true if the function has boolean return type
+ */
+fun ASTNode.hasBooleanReturnType(): Boolean {
+    val functionReturnType = this.findChildAfter(VALUE_PARAMETER_LIST, KtNodeTypes.TYPE_REFERENCE)?.text
+    return functionReturnType != null && functionReturnType == PrimitiveType.BOOLEAN.typeName.asString()
+}
+
+/**
+ * Checks if the function is an operator function
+ *
+ * @return true if the function is an operator function
+ */
+fun ASTNode.isOperatorFun(): Boolean {
+    val modifierListNode = this.findChildByType(MODIFIER_LIST)
+    return modifierListNode?.hasChildMatching { it.elementType == KtTokens.OPERATOR_KEYWORD } ?: false
+}
+
 /**
  * Checks if the symbols in this node are at the end of line
  */

diff --git a/...rules/src/test/kotlin/com/saveourtool/diktat/ruleset/chapter1/IdentifierNamingWarnTest.kt b/...rules/src/test/kotlin/com/saveourtool/diktat/ruleset/chapter1/IdentifierNamingWarnTest.kt
@@ -1,3 +1,7 @@
+@file:Suppress(
+    "LargeClass"
+)
+
 package com.saveourtool.diktat.ruleset.chapter1
 
 import com.saveourtool.diktat.common.config.rules.DIKTAT_RULE_SET_ID
@@ -447,6 +451,16 @@ class IdentifierNamingWarnTest : LintTestBase(::IdentifierNaming) {
         )
     }
 
+    @Test
+    @Tag(WarningNames.FUNCTION_BOOLEAN_PREFIX)
+    fun `fixed false positive result on operator functions`() {
+        lintMethod(
+            """
+                    inline operator fun component3(): Boolean = asDynamic()[2].unsafeCast<Boolean>()
+            """.trimIndent()
+        )
+    }
+
     @Test
     @Tag(WarningNames.IDENTIFIER_LENGTH)
     fun `regression - function argument type`() {