Gradle IC: treat companion object change as class signature change

build-common/src/org/jetbrains/kotlin/incremental/protoDifferenceUtils.kt

@@ -190,6 +190,7 @@ private class DifferenceCalculatorForClass(oldData: ProtoMapValue, newData: Prot
                 ProtoBufClassKind.COMPANION_OBJECT_NAME -> {
                     if (oldProto.hasCompanionObjectName()) oldProto.companionObjectName.oldToNames()
                     if (newProto.hasCompanionObjectName()) newProto.companionObjectName.newToNames()
+                    isClassAffected = true
                 }
                 ProtoBufClassKind.NESTED_CLASS_NAME_LIST -> {
                     if (classIsSealed) {

jps-plugin/testData/comparison/classMembersOnlyChanged/classWithCompanionObjectChanged/result.out

@@ -2,11 +2,11 @@ REMOVED: class ClassWithChangedCompanionObject$FirstName.class
 REMOVED: class ClassWithRemovedCompanionObject$Companion.class
 ADDED: class ClassWithAddedCompanionObject$Companion.class
 ADDED: class ClassWithChangedCompanionObject$SecondName.class
-changes in test/ClassWithAddedCompanionObject: MEMBERS
+changes in test/ClassWithAddedCompanionObject: CLASS_SIGNATURE, MEMBERS
     [Companion]
-changes in test/ClassWithChangedCompanionObject: MEMBERS
+changes in test/ClassWithChangedCompanionObject: CLASS_SIGNATURE, MEMBERS
     [FirstName, SecondName]
 changes in test/ClassWithChangedVisibilityForCompanionObject.Companion: CLASS_SIGNATURE
 changes in test/ClassWithChangedVisibilityForCompanionObject: NONE
-changes in test/ClassWithRemovedCompanionObject: MEMBERS
+changes in test/ClassWithRemovedCompanionObject: CLASS_SIGNATURE, MEMBERS
     [Companion]

jps-plugin/testData/incremental/classHierarchyAffected/companionObjectToSimpleObject/build.log

@@ -10,6 +10,7 @@ End of files
 Marked as dirty by Kotlin:
   src/companionExtension.kt
   src/companionReferenceExplicit.kt
+  src/companionReferenceImplicit.kt
 Exit code: ADDITIONAL_PASS_REQUIRED
 ------------------------------------------
 Cleaning output files:

jps-plugin/testData/incremental/pureKotlin/removeAndRestoreCompanion/experimental-ic-build.log

@@ -8,16 +8,19 @@ Compiling files:
   src/A.kt
 End of files
 Marked as dirty by Kotlin:
+  src/useA.kt
   src/useAbar.kt
   src/useAfoo.kt
 Exit code: ADDITIONAL_PASS_REQUIRED
 ------------------------------------------
 Cleaning output files:
   out/production/module/META-INF/module.kotlin_module
+  out/production/module/use/UseAKt.class
   out/production/module/use/UseAbarKt.class
   out/production/module/use/UseAfooKt.class
 End of files
 Compiling files:
+  src/useA.kt
   src/useAbar.kt
   src/useAfoo.kt
 End of files
@@ -34,8 +37,9 @@ Cleaning output files:
 End of files
 Compiling files:
   src/A.kt
+  src/useA.kt
   src/useAbar.kt
   src/useAfoo.kt
 End of files
 Exit code: OK
-------------------------------------------
+------------------------------------------