KDOC_WITHOUT_THROWS_TAG add @throws annotation when throw inside try-catch

diktat-rules/src/main/kotlin/com/saveourtool/diktat/ruleset/rules/chapter2/kdoc/KdocMethods.kt

@@ -12,6 +12,7 @@ import com.saveourtool.diktat.ruleset.utils.KotlinParser
 import com.saveourtool.diktat.ruleset.utils.appendNewlineMergingWhiteSpace
 import com.saveourtool.diktat.ruleset.utils.findAllDescendantsWithSpecificType
 import com.saveourtool.diktat.ruleset.utils.findChildAfter
+import com.saveourtool.diktat.ruleset.utils.getAllChildrenWithType
 import com.saveourtool.diktat.ruleset.utils.getBodyLines
 import com.saveourtool.diktat.ruleset.utils.getFilePath
 import com.saveourtool.diktat.ruleset.utils.getFirstChildWithType
@@ -40,6 +41,7 @@ import org.jetbrains.kotlin.KtNodeTypes.MODIFIER_LIST
 import org.jetbrains.kotlin.KtNodeTypes.REFERENCE_EXPRESSION
 import org.jetbrains.kotlin.KtNodeTypes.THIS_EXPRESSION
 import org.jetbrains.kotlin.KtNodeTypes.THROW
+import org.jetbrains.kotlin.KtNodeTypes.TRY
 import org.jetbrains.kotlin.KtNodeTypes.TYPE_REFERENCE
 import org.jetbrains.kotlin.com.intellij.lang.ASTFactory
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
@@ -54,6 +56,7 @@ import org.jetbrains.kotlin.kdoc.psi.impl.KDocTag
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.lexer.KtTokens.COLON
 import org.jetbrains.kotlin.lexer.KtTokens.EQ
+import org.jetbrains.kotlin.lexer.KtTokens.IDENTIFIER
 import org.jetbrains.kotlin.lexer.KtTokens.WHITE_SPACE
 import org.jetbrains.kotlin.psi.KtCallExpression
 import org.jetbrains.kotlin.psi.KtCatchClause
@@ -62,6 +65,7 @@ import org.jetbrains.kotlin.psi.KtFunction
 import org.jetbrains.kotlin.psi.KtThrowExpression
 import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
 import org.jetbrains.kotlin.psi.psiUtil.referenceExpression
+import java.lang.Class.forName
 
 /**
  * This rule checks that whenever the method has arguments, return value, can throw exceptions,
@@ -197,11 +201,42 @@ class KdocMethods(configRules: List<RulesConfig>) : DiktatRule(
                 && !hasReturnKdoc && !isReferenceExpressionWithSameName
     }
 
+    private fun isThrowInTryCatchBlock(node: ASTNode?): Boolean {
+        node ?: return false
+        var parent = node.treeParent
+        while (parent != null && parent.elementType != TRY) {
+            parent = parent.treeParent
+        }
+        val nodeName = node.findAllDescendantsWithSpecificType(IDENTIFIER).firstOrNull() ?: return false
+
+        if (parent?.elementType == TRY) {
+            val catchNodes = parent.getAllChildrenWithType(CATCH)
+            val findNodeWithMatchingName = catchNodes.firstOrNull { catchNode ->
+                val matchingNameForCatchNode = catchNode.findAllDescendantsWithSpecificType(IDENTIFIER)
+                    .firstOrNull { catchNodeName ->
+                        nodeName.text == catchNodeName.text || try {
+                            val nodeClass = forName("java.lang.${nodeName.text}")
+                            val nodeInstance = nodeClass.getDeclaredConstructor().newInstance()
+                            val catchNodeClass = forName("java.lang.${catchNodeName.text}")
+                            catchNodeClass.isInstance(nodeInstance)
+                        } catch (e: ClassNotFoundException) {
+                            false
+                        }
+                    }
+                matchingNameForCatchNode != null
+            }
+            return findNodeWithMatchingName != null
+        }
+        return false
+    }
+
     private fun getExplicitlyThrownExceptions(node: ASTNode): Set<String> {
         val codeBlock = node.getFirstChildWithType(BLOCK)
         val throwKeywords = codeBlock?.findAllDescendantsWithSpecificType(THROW)
+
         return throwKeywords
             ?.asSequence()
+            ?.filter { !isThrowInTryCatchBlock(it) }
             ?.map { it.psi as KtThrowExpression }
             ?.filter {
                 // we only take freshly created exceptions here: `throw IAE("stuff")` vs `throw e`

diktat-rules/src/test/kotlin/com/saveourtool/diktat/ruleset/chapter2/KdocMethodsFixTest.kt

@@ -61,4 +61,10 @@ class KdocMethodsFixTest : FixTestBase("test/paragraph2/kdoc/package/src/main/ko
     fun `KdocMethods rule should reformat code (full example)`() {
         fixAndCompare("KdocMethodsFullExpected.kt", "KdocMethodsFullTested.kt")
     }
+
+    @Test
+    @Tag(WarningNames.KDOC_WITHOUT_THROWS_TAG)
+    fun `@throws tag shouldn't be added inside try-catch`() {
+        fixAndCompare("KdocWithoutThrowsTagExpected.kt", "KdocWithoutThrowsTagTested.kt")
+    }
 }

diktat-rules/src/test/kotlin/com/saveourtool/diktat/ruleset/chapter2/KdocMethodsTest.kt

@@ -272,6 +272,81 @@ class KdocMethodsTest : LintTestBase(::KdocMethods) {
         )
     }
 
+    @Test
+    @Tag(WarningNames.KDOC_WITHOUT_THROWS_TAG)
+    fun `No warning when catch without matching throw`() {
+        lintMethod(
+            """
+                    /**
+                      * Test method
+                      * @param a: Int - dummy integer
+                      * @return doubled value
+                      */
+                    fun foo(a: Int): Int {
+                        try {
+                            if (a < 0)
+                                throw NumberFormatExecption()
+                        } catch (e: ArrayIndexOutOfBounds) {
+                            print(1)
+                        } catch (e: NullPointerException) {
+                            print(2)
+                        } catch (e: NumberFormatExecption) {
+                            print(3)
+                        }
+                        return 2 * a
+                    }
+            """.trimIndent())
+    }
+
+    @Test
+    @Tag(WarningNames.KDOC_WITHOUT_THROWS_TAG)
+    fun `Warning when throw doesn't have matching catch`() {
+        lintMethod(
+            """
+                    /**
+                      * Test method
+                      * @param a: Int - dummy integer
+                      * @return doubled value
+                      */
+                    fun foo(a: Int): Int {
+                        try {
+                            if (a < 0)
+                                throw NumberFormatException()
+                        throw NullPointerException()
+                        throw NoSuchElementException()
+                        } catch (e: NoSuchElementException) {
+                            print(1)
+                        } catch (e: IllegalArgumentException) {
+                            print(2)
+                        }
+                        return 2 * a
+                    }
+            """.trimIndent(),
+        DiktatError(1, 1, ruleId, "${KDOC_WITHOUT_THROWS_TAG.warnText()} foo (NullPointerException)", true))
+    }
+
+    @Test
+    @Tag(WarningNames.KDOC_WITHOUT_THROWS_TAG)
+    fun `No warning when throw has matching catch, which is parent exception to throw`() {
+        lintMethod(
+            """
+                    /**
+                      * Test method
+                      * @param a: Int - dummy integer
+                      * @return doubled value
+                      */
+                    fun foo(a: Int): Int {
+                        try {
+                            if (a < 0)
+                                throw NumberFormatException()
+                        } catch (e: IllegalArgumentException) {
+                            print(1)
+                        }
+                        return 2 * a
+                    }
+            """.trimIndent())
+    }
+
     @Test
     @Tag(WarningNames.MISSING_KDOC_TOP_LEVEL)
     fun `do not force documentation on standard methods`() {

diktat-rules/src/test/resources/test/paragraph2/kdoc/package/src/main/kotlin/com/saveourtool/diktat/kdoc/methods/KdocWithoutThrowsTagExpected.kt

@@ -0,0 +1,22 @@
+package test.paragraph2.kdoc.`package`.src.main.kotlin.com.saveourtool.diktat.kdoc.methods
+
+/**
+ * @param onSuccess
+ * @param onFailure
+ * @throws ArrayIndexOutOfBounds
+ */
+fun parseInputNumber(onSuccess: (number: Int) -> Unit, onFailure: () -> Unit) {
+    try {
+        val input: Int = binding.inputEditText.text.toString().toInt()
+        if (input < 0)
+            throw NumberFormatException()
+        throw ArrayIndexOutOfBounds()
+        throw NullPointerException()
+
+        onSuccess(input)
+    } catch (e: IllegalArgumentException) {
+        onFailure()
+    } catch (e: NullPointerException) {
+        onFailure()
+    }
+}

diktat-rules/src/test/resources/test/paragraph2/kdoc/package/src/main/kotlin/com/saveourtool/diktat/kdoc/methods/KdocWithoutThrowsTagTested.kt

@@ -0,0 +1,21 @@
+package test.paragraph2.kdoc.`package`.src.main.kotlin.com.saveourtool.diktat.kdoc.methods
+
+/**
+ * @param onSuccess
+ * @param onFailure
+ */
+fun parseInputNumber(onSuccess: (number: Int) -> Unit, onFailure: () -> Unit) {
+    try {
+        val input: Int = binding.inputEditText.text.toString().toInt()
+        if (input < 0)
+            throw NumberFormatException()
+        throw ArrayIndexOutOfBounds()
+        throw NullPointerException()
+
+        onSuccess(input)
+    } catch (e: IllegalArgumentException) {
+        onFailure()
+    } catch (e: NullPointerException) {
+        onFailure()
+    }
+}