Support finding descriptors for java statics (#171)

* Handle statics in resolveJavaDeclaration

This PR fixes a bug where static java declarations were not being resolved
properly because we would only look at the main scope of the class declaration
but we also need to check the static scope.

Author: yigit

compiler-plugin/src/main/kotlin/com/google/devtools/ksp/processing/impl/ResolverImpl.kt

@@ -72,8 +72,9 @@ import org.jetbrains.kotlin.resolve.lazy.ForceResolveUtil
 import org.jetbrains.kotlin.resolve.lazy.ResolveSession
 import org.jetbrains.kotlin.resolve.multiplatform.findActuals
 import org.jetbrains.kotlin.resolve.multiplatform.findExpects
+import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.resolve.scopes.LexicalScope
-import org.jetbrains.kotlin.resolve.scopes.getDescriptorsFiltered
+import org.jetbrains.kotlin.resolve.scopes.MemberScope
 import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.typeUtil.replaceArgumentsWithStarProjections
 import org.jetbrains.kotlin.types.typeUtil.substitute
@@ -317,17 +318,30 @@ class ResolverImpl(
             is PsiMethod -> {
                 // TODO: get rid of hardcoded check if possible.
                 if (psi.name.startsWith("set") || psi.name.startsWith("get")) {
-                    moduleClassResolver.resolveClass(JavaMethodImpl(psi).containingClass)
-                            ?.unsubstitutedMemberScope!!.getDescriptorsFiltered().singleOrNull{
-                                (it as? PropertyDescriptor)?.getter?.findPsi() == psi || (it as? PropertyDescriptor)?.setter?.findPsi() == psi
-                            }
+                    moduleClassResolver
+                        .resolveClass(JavaMethodImpl(psi).containingClass)
+                        ?.findEnclosedDescriptor(
+                            kindFilter = DescriptorKindFilter.CALLABLES
+                        ) {
+                            (it as? PropertyDescriptor)?.getter?.findPsi() == psi || (it as? PropertyDescriptor)?.setter?.findPsi() == psi
+                        }
                 } else {
-                    moduleClassResolver.resolveClass(JavaMethodImpl(psi).containingClass)
-                            ?.unsubstitutedMemberScope!!.getDescriptorsFiltered().singleOrNull { it.findPsi() == psi }
+                    moduleClassResolver
+                        .resolveClass(JavaMethodImpl(psi).containingClass)
+                        ?.findEnclosedDescriptor(
+                            kindFilter = DescriptorKindFilter.FUNCTIONS,
+                            filter = { it.findPsi() == psi }
+                        )
                 }
             }
-            is PsiField -> moduleClassResolver.resolveClass(JavaFieldImpl(psi).containingClass)
-                ?.unsubstitutedMemberScope!!.getDescriptorsFiltered().single { it.findPsi() == psi } as CallableMemberDescriptor
+            is PsiField -> {
+                moduleClassResolver
+                    .resolveClass(JavaFieldImpl(psi).containingClass)
+                    ?.findEnclosedDescriptor(
+                        kindFilter = DescriptorKindFilter.VARIABLES,
+                        filter = { it.findPsi() == psi }
+                    )
+            }
             else -> throw IllegalStateException("unhandled psi element kind: ${psi.javaClass}")
         }
     }
@@ -422,9 +436,16 @@ class ResolverImpl(
                     val containingDeclaration = if (psi.owner is PsiClass) {
                         moduleClassResolver.resolveClass(JavaClassImpl(psi.owner as PsiClass))
                     } else {
+                        val owner = psi.owner
+                        check(owner is PsiMethod) {
+                            "unexpected owner type: $owner / ${owner?.javaClass}"
+                        }
                         moduleClassResolver.resolveClass(
-                            JavaMethodImpl(psi.owner as PsiMethod).containingClass
-                        )?.unsubstitutedMemberScope!!.getDescriptorsFiltered().single { it.findPsi() == psi.owner } as FunctionDescriptor
+                            JavaMethodImpl(owner).containingClass
+                        )?.findEnclosedDescriptor(
+                            kindFilter = DescriptorKindFilter.FUNCTIONS,
+                            filter = { it.findPsi() == owner }
+                        ) as FunctionDescriptor
                     } as DeclarationDescriptor
                     return getKSTypeCached(
                         LazyJavaTypeParameterDescriptor(
@@ -697,3 +718,25 @@ private fun Name.getNonSpecialIdentifier() :String {
         asString().substring(1)
     }
 }
+
+private inline fun MemberScope.findEnclosedDescriptor(
+    kindFilter: DescriptorKindFilter,
+    crossinline filter: (DeclarationDescriptor) -> Boolean
+) : DeclarationDescriptor? {
+    return getContributedDescriptors(
+        kindFilter = kindFilter
+    ).firstOrNull(filter)
+}
+
+private inline fun ClassDescriptor.findEnclosedDescriptor(
+    kindFilter: DescriptorKindFilter,
+    crossinline filter: (DeclarationDescriptor) -> Boolean
+) : DeclarationDescriptor? {
+    return this.unsubstitutedMemberScope.findEnclosedDescriptor(
+        kindFilter = kindFilter,
+        filter = filter
+    ) ?: this.staticScope.findEnclosedDescriptor(
+        kindFilter = kindFilter,
+        filter = filter
+    )
+}

compiler-plugin/testData/api/mangledNames.kt

@@ -40,6 +40,9 @@
 // fileLevelInlineReturningFun -> fileLevelInlineReturningFun
 // fileLevelInternalInlineReceivingFun -> fileLevelInternalInlineReceivingFun-E03SJzc
 // fileLevelInternalInlineReturningFun -> fileLevelInternalInlineReturningFun
+// JavaInput -> declarations
+// javaFunction -> javaFunction
+// staticJavaFunction -> staticJavaFunction
 // libPackage.Foo -> declarations
 // get-inlineProp -> getInlineProp-b_MPbnQ
 // set-inlineProp -> setInlineProp-mQ73O9w
@@ -108,3 +111,11 @@ fun fileLevelInlineReceivingFun(inline1: Inline1): Unit = TODO()
 fun fileLevelInlineReturningFun(): Inline1 = TODO()
 fun fileLevelInternalInlineReceivingFun(inline1: Inline1): Unit = TODO()
 fun fileLevelInternalInlineReturningFun(): Inline1 = TODO()
+
+// FILE: JavaInput.java
+class JavaInput {
+    String javaField;
+    String javaFunction() {}
+    static String staticJavaField;
+    static void staticJavaFunction() {}
+}