Removed UnnecessaryAbstractClass if it inherits from a abstract class (…

…#5009)

* Removed UnnecessaryAbstractClass if it inherits from an interface or abstract class that has concrete members

Removed deprecated annotations

Revert "Removed deprecated annotations"

This reverts commit 326a356

fix return count rule violation

* Removed UnnecessaryAbstractClass if it inherits from an interface or abstract class that has concrete members

Removed deprecated annotations

Revert "Removed deprecated annotations"

This reverts commit 326a356

fix return count rule violation

* Handle corner case of multiple inheritance in UnnecessaryAbstractClass rule

Co-authored-by: Amit Dash <amitdash291@gmail.com>

detekt-rules-style/src/main/kotlin/io/gitlab/arturbosch/detekt/rules/style/UnnecessaryAbstractClass.kt

@@ -22,6 +22,8 @@ import org.jetbrains.kotlin.psi.KtClass
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.psiUtil.isAbstract
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.lazy.descriptors.LazyClassMemberScope
+import org.jetbrains.kotlin.types.typeUtil.isInterface
 
 /**
  * This rule inspects `abstract` classes. In case an `abstract class` does not have any concrete members it should be
@@ -86,6 +88,7 @@ class UnnecessaryAbstractClass(config: Config = Config.empty) : Rule(config) {
         val members = members()
         when {
             members.isNotEmpty() -> checkMembers(members, nameIdentifier)
+            hasInheritedMember(true) && isAnyParentAbstract() -> return
             !hasConstructorParameter() ->
                 report(CodeSmell(issue, Entity.from(nameIdentifier), noConcreteMember))
             else ->
@@ -125,4 +128,9 @@ class UnnecessaryAbstractClass(config: Config = Config.empty) : Rule(config) {
             }
         }
     }
+
+    private fun KtClass.isAnyParentAbstract() =
+        (bindingContext[BindingContext.CLASS, this]?.unsubstitutedMemberScope as? LazyClassMemberScope)
+            ?.supertypes
+            ?.all { it.isInterface() } == false
 }

detekt-rules-style/src/test/kotlin/io/gitlab/arturbosch/detekt/rules/style/UnnecessaryAbstractClassSpec.kt

@@ -86,8 +86,37 @@ class UnnecessaryAbstractClassSpec(val env: KotlinCoreEnvironment) {
                     }
                     abstract class B : A()
                 """
+                assertThat(subject.compileAndLintWithContext(env, code)).isEmpty()
+            }
+
+            @Test
+            fun `does not report abstract class that inherits from an abstract class and an interface in that order`() {
+                val code = """
+                interface I
+
+                @Deprecated("We don't care about this first class")
+                abstract class A {
+                    abstract val i: Int
+                }
+                abstract class B: A(), I
+            """
                 val findings = subject.compileAndLintWithContext(env, code)
-                assertFindingMessage(findings, message)
+                assertThat(findings).isEmpty()
+            }
+
+            @Test
+            fun `does not report abstract class that inherits from an interface and an abstract class in that order`() {
+                val code = """
+                interface I
+
+                @Deprecated("We don't care about this first class")
+                abstract class A {
+                    abstract val i: Int
+                }
+                abstract class B: I, A()
+            """
+                val findings = subject.compileAndLintWithContext(env, code)
+                assertThat(findings).isEmpty()
             }
         }