parse the declarations of named companion objects and their members

fixes #705

Author: RBusarow

modulecheck-core/src/test/kotlin/modulecheck/core/UnusedDependenciesTest.kt

@@ -834,6 +834,136 @@ class UnusedDependenciesTest : RunnerTest() {
       .clean() shouldBe """ModuleCheck found 0 issues"""
   }
 
+  @Test
+  fun `module contributing a named companion object, consumed in the same package should not be unused`() {
+    // https://github.com/RBusarow/ModuleCheck/issues/705
+
+    settings.deleteUnused = false
+
+    val lib1 = kotlinProject(":lib1") {
+      addKotlinSource(
+        """
+        package com.modulecheck.common
+
+        class Lib1Class {
+          companion object Factory {
+            fun create() = Lib1Class()
+          }
+        }
+        """.trimIndent()
+      )
+    }
+
+    val lib2 = kotlinProject(":lib2") {
+      addDependency(ConfigurationName.implementation, lib1)
+
+      buildFile {
+        """
+        plugins {
+          kotlin("jvm")
+        }
+
+        dependencies {
+          implementation(project(path = ":lib1"))
+        }
+        """
+      }
+
+      addKotlinSource(
+        """
+        package com.modulecheck.common
+
+        fun foo() {
+          bar(Lib1Class.create())
+        }
+
+        fun bar(any: Any) = Unit
+        """.trimIndent(),
+        SourceSetName.MAIN
+      )
+    }
+
+    run().isSuccess shouldBe true
+
+    lib2.buildFile shouldHaveText """
+        plugins {
+          kotlin("jvm")
+        }
+
+        dependencies {
+          implementation(project(path = ":lib1"))
+        }
+    """
+
+    logger.parsedReport() shouldBe listOf()
+  }
+
+  @Test
+  fun `module contributing a named companion object, consumed by the companion name should not be unused`() {
+    // https://github.com/RBusarow/ModuleCheck/issues/705
+
+    settings.deleteUnused = false
+
+    val lib1 = kotlinProject(":lib1") {
+      addKotlinSource(
+        """
+        package com.modulecheck.common
+
+        class Lib1Class {
+          companion object Factory {
+            fun create() = Lib1Class()
+          }
+        }
+        """.trimIndent()
+      )
+    }
+
+    val lib2 = kotlinProject(":lib2") {
+      addDependency(ConfigurationName.implementation, lib1)
+
+      buildFile {
+        """
+        plugins {
+          kotlin("jvm")
+        }
+
+        dependencies {
+          implementation(project(path = ":lib1"))
+        }
+        """
+      }
+
+      addKotlinSource(
+        """
+        package com.modulecheck.common
+
+        import com.modulecheck.common.Lib1Class.Factory
+
+        fun foo() {
+          bar(Factory.create())
+        }
+
+        fun bar(any: Any) = Unit
+        """.trimIndent(),
+        SourceSetName.MAIN
+      )
+    }
+
+    run().isSuccess shouldBe true
+
+    lib2.buildFile shouldHaveText """
+        plugins {
+          kotlin("jvm")
+        }
+
+        dependencies {
+          implementation(project(path = ":lib1"))
+        }
+    """
+
+    logger.parsedReport() shouldBe listOf()
+  }
+
   @Test
   fun `testImplementation used in test should not be unused`() {
 

modulecheck-parsing/psi/src/main/kotlin/modulecheck/parsing/psi/RealKotlinFile.kt

@@ -22,6 +22,8 @@ import modulecheck.parsing.psi.internal.callSiteName
 import modulecheck.parsing.psi.internal.getByNameOrIndex
 import modulecheck.parsing.psi.internal.getChildrenOfTypeRecursive
 import modulecheck.parsing.psi.internal.identifier
+import modulecheck.parsing.psi.internal.isCompanionObject
+import modulecheck.parsing.psi.internal.isInCompanionObject
 import modulecheck.parsing.psi.internal.isJvmStatic
 import modulecheck.parsing.psi.internal.isPartOf
 import modulecheck.parsing.psi.internal.isPrivateOrInternal
@@ -146,18 +148,29 @@ class RealKotlinFile(
         }
       }
 
+      val psi = this@declaredNames
+
+      fun parseCompanionObjectDeclarations(companionName: String) {
+        both(nameAsString)
+
+        if (isStatic()) {
+          both(nameAsString.remove(".$companionName"))
+        } else if (psi is KtCallableDeclaration) {
+          kotlin(nameAsString.remove(".$companionName"))
+        }
+      }
+
       when {
-        nameAsString.contains(".Companion") -> {
-          both(nameAsString)
+        psi.isCompanionObject() -> {
+          parseCompanionObjectDeclarations(psi.name ?: "Companion")
+        }
 
-          if (isStatic()) {
-            both(nameAsString.remove(".Companion"))
-          } else if (this@declaredNames is KtCallableDeclaration) {
-            kotlin(nameAsString.remove(".Companion"))
-          }
+        psi.isInCompanionObject() -> {
+          val companion = containingClassOrObject as KtObjectDeclaration
+          parseCompanionObjectDeclarations(companion.name ?: "Companion")
         }
 
-        isTopLevelKtOrJavaMember() && this@declaredNames !is KtClassOrObject && !isStatic() -> {
+        isTopLevelKtOrJavaMember() && psi !is KtClassOrObject && !isStatic() -> {
           kotlin(nameAsString)
 
           jvmSimpleNames().forEach {
@@ -190,7 +203,7 @@ class RealKotlinFile(
 
           val jvmNames = jvmSimpleNames()
 
-          if (this@declaredNames is KtFunction && jvmNameOrNull() == null) {
+          if (psi is KtFunction && psi.jvmNameOrNull() == null) {
             both(nameAsString)
           } else {
             kotlin(nameAsString)
@@ -204,8 +217,7 @@ class RealKotlinFile(
           }
         }
 
-        this@declaredNames is KtParameter ||
-          (this@declaredNames is KtProperty && !isTopLevelKtOrJavaMember()) -> {
+        psi is KtParameter || (psi is KtProperty && !psi.isTopLevelKtOrJavaMember()) -> {
 
           kotlin(nameAsString)
 

modulecheck-parsing/psi/src/main/kotlin/modulecheck/parsing/psi/internal/psiElement.kt

@@ -28,7 +28,6 @@ import org.jetbrains.kotlin.psi.KtAnnotationEntry
 import org.jetbrains.kotlin.psi.KtBlockExpression
 import org.jetbrains.kotlin.psi.KtCallExpression
 import org.jetbrains.kotlin.psi.KtClassLiteralExpression
-import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtDotQualifiedExpression
 import org.jetbrains.kotlin.psi.KtNameReferenceExpression
@@ -50,6 +49,7 @@ import org.jetbrains.kotlin.psi.psiUtil.isObjectLiteral
 import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import java.io.File
+import kotlin.contracts.contract
 
 inline fun <reified T : PsiElement> PsiElement.isPartOf() = getNonStrictParentOfType<T>() != null
 
@@ -126,6 +126,7 @@ suspend fun PsiElement.fqNameOrNull(
         ?.let { return it }
         ?: text
     }
+
     is KtNameReferenceExpression -> getReferencedName()
     is KtUserType -> {
       val isGenericType = children.any { it is KtTypeArgumentList }
@@ -163,6 +164,7 @@ suspend fun PsiElement.fqNameOrNull(
         text
       }
     }
+
     is KtTypeReference -> {
       val children = children
       if (children.size == 1) {
@@ -173,13 +175,15 @@ suspend fun PsiElement.fqNameOrNull(
         text
       }
     }
+
     is KtNullableType -> return innerType?.fqNameOrNull(project, sourceSetName)
     is KtAnnotationEntry -> return typeReference?.fqNameOrNull(project, sourceSetName)
     is KtClassLiteralExpression -> {
       // Returns "Abc" for "Abc::class".
       return children.singleOrNull()
         ?.fqNameOrNull(project, sourceSetName)
     }
+
     is KtSuperTypeListEntry -> return typeReference?.fqNameOrNull(project, sourceSetName)
     else -> return null
   }
@@ -197,6 +201,7 @@ suspend fun PsiElement.fqNameOrNull(
       when {
         matchingImportPaths.size == 1 ->
           return matchingImportPaths[0].fqName
+
         matchingImportPaths.size > 1 ->
           return matchingImportPaths.firstOrNull { importPath ->
             project.canResolveFqName(importPath.fqName, sourceSetName)
@@ -210,6 +215,7 @@ suspend fun PsiElement.fqNameOrNull(
       when {
         matchingImportPaths.size == 1 ->
           return FqName("${matchingImportPaths[0].fqName.parent()}.$classReference")
+
         matchingImportPaths.size > 1 ->
           return matchingImportPaths.firstOrNull { importPath ->
             project.canResolveFqName(
@@ -257,10 +263,24 @@ suspend fun PsiElement.fqNameOrNull(
 
 fun KtDeclaration.isInObject() = containingClassOrObject?.isObjectLiteral() ?: false
 
-fun KtDeclaration.isInCompanionObject() = containingClassOrObject?.isCompanionObject() ?: false
+/**
+ * @return true if the receiver declaration is inside a companion object
+ */
+fun KtDeclaration.isInCompanionObject(): Boolean {
+  return containingClassOrObject?.isCompanionObject() ?: false
+}
+
 fun KtDeclaration.isInObjectOrCompanionObject() = isInObject() || isInCompanionObject()
 
-fun KtClassOrObject.isCompanionObject(): Boolean = this is KtObjectDeclaration && isCompanion()
+/**
+ * @return true if the receiver declaration is a companion object
+ */
+fun KtDeclaration.isCompanionObject(): Boolean {
+  contract {
+    returns(true) implies (this@isCompanionObject is KtObjectDeclaration)
+  }
+  return this is KtObjectDeclaration && isCompanion()
+}
 
 fun PsiElement.isQualifiedPropertyOrCallExpression(): Boolean {
   // properties which are qualified have a direct parent of `KtQualifiedExpression`

modulecheck-parsing/psi/src/test/kotlin/modulecheck/parsing/psi/KotlinFileTest.kt

@@ -455,6 +455,39 @@ internal class KotlinFileTest : ProjectTest(), NamedSymbolTest {
     }
   }
 
+  @Test
+  fun `named companion object and function should also have declarations using original class name`() =
+    test {
+
+      val project = kotlinProject(":subject")
+
+      val file = project.createFile(
+        """
+      package com.subject
+
+      class SubjectClass {
+
+        companion object Factory {
+          fun create() = SubjectClass()
+        }
+      }
+      """
+      )
+
+      file shouldBe {
+        references {
+          interpretedKotlin("SubjectClass")
+          interpretedKotlin("com.subject.SubjectClass")
+        }
+        declarations {
+          agnostic("com.subject.SubjectClass")
+          agnostic("com.subject.SubjectClass.Factory")
+          agnostic("com.subject.SubjectClass.Factory.create")
+          kotlin("com.subject.SubjectClass.create")
+        }
+      }
+    }
+
   @Test
   fun `explicit fully qualified type of public property in public class should be api reference`() =
     test {