KTIJ-26423 [kotlin] Properly resolve conflicting classes in OptimizedImportsBuilder

This is not all the conflicts resolution that is
required for 100% correct Import Optimizer
implementation, but it suffices most of the time.

GitOrigin-RevId: 7732d85966c678efe2ffe7f78328daed50622af9

plugins/kotlin/code-insight/kotlin.code-insight.k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/imports/HierarchicalScope.kt

@@ -0,0 +1,36 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package org.jetbrains.kotlin.idea.k2.codeinsight.imports
+
+import org.jetbrains.kotlin.analysis.api.KaSession
+import org.jetbrains.kotlin.analysis.api.components.KaScopeContext
+import org.jetbrains.kotlin.analysis.api.scopes.KaScope
+import org.jetbrains.kotlin.analysis.api.symbols.KaClassifierSymbol
+import org.jetbrains.kotlin.name.Name
+
+internal class HierarchicalScope private constructor(private val scopes: List<KaScope>) {
+
+    /**
+     * Finds classifier symbols corresponding to the given name across the scope layers.
+     *
+     * Symbols from higher priority scope layers are returned first.
+     *
+     * Each list in the sequence represents classifiers found in a single scopes layer.
+     */
+    fun findClassifiers(name: Name): Sequence<List<KaClassifierSymbol>> {
+        return scopes.asSequence()
+            .map { it.classifiers(name).toList() }
+            .filter { it.isNotEmpty() }
+    }
+
+    companion object {
+        fun KaSession.createFrom(scopeContext: KaScopeContext): HierarchicalScope {
+            val scopeGroupsSorted = scopeContext.scopes
+                .groupBy({ it.kind }, { it.scope })
+                .toSortedMap(compareByDescending { it.indexInTower })
+
+            val scopes = scopeGroupsSorted.values.map { it.asCompositeScope() }
+
+            return HierarchicalScope(scopes)
+        }
+    }
+}

plugins/kotlin/code-insight/kotlin.code-insight.k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/imports/OptimizedImportsBuilder.kt

@@ -15,6 +15,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtImportDirective
 import org.jetbrains.kotlin.resolve.ImportPath
+import kotlin.collections.filter
 
 internal fun KaSession.buildOptimizedImports(
     file: KtFile,
@@ -51,8 +52,8 @@ internal class OptimizedImportsBuilder(
 
                 val parentFqName = resultFqName.parent()
                 if (
-                    alias == null
-                    && canUseStarImport(importableSymbol, resultFqName) &&
+                    alias == null &&
+                    canUseStarImport(importableSymbol, resultFqName) &&
                     ImportPath(parentFqName, isAllUnder = true).isAllowedByRules()
                 ) {
                     symbolsByParentFqName.getOrPut(parentFqName) { hashSetOf() }.add(importableSymbol)
@@ -88,6 +89,30 @@ internal class OptimizedImportsBuilder(
             }
         }
 
+        val importingScopeContext = buildScopeContextByImports(file, importsToGenerate.filter { it.isAllUnder })
+        val importingScopes = HierarchicalScope.run { createFrom(importingScopeContext) }
+
+        for (fqName in classNamesToCheck) {
+            val foundClassifiers = importingScopes.findClassifiers(fqName.shortName()).firstOrNull()
+            val singleFoundClassifier = foundClassifiers?.singleOrNull()
+
+            if (singleFoundClassifier?.importableFqName != fqName) {
+                // add explicit import if failed to import with * (or from current package)
+                importsToGenerate.add(ImportPath(fqName, false))
+
+                val parentFqName = fqName.parent()
+
+                val siblingsToImport = symbolsByParentFqName.getValue(parentFqName)
+                for (descriptor in siblingsToImport.filter { it.run {computeImportableName() } == fqName }) {
+                    siblingsToImport.remove(descriptor)
+                }
+
+                if (siblingsToImport.isEmpty()) { // star import is not really needed
+                    importsToGenerate.remove(ImportPath(parentFqName, true))
+                }
+            }
+        }
+
         val sortedImportsToGenerate = importsToGenerate.sortedWith(KotlinImportPathComparator.create(file))
 
         val oldImports = file.importDirectives

plugins/kotlin/code-insight/kotlin.code-insight.k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/imports/scopeUtils.kt

@@ -0,0 +1,33 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package org.jetbrains.kotlin.idea.k2.codeinsight.imports
+
+import org.jetbrains.kotlin.analysis.api.KaSession
+import org.jetbrains.kotlin.analysis.api.components.KaScopeContext
+import org.jetbrains.kotlin.psi.KtBlockCodeFragment
+import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.resolve.ImportPath
+
+internal fun KaSession.buildScopeContextByImports(originalFile: KtFile, importsToGenerate: Collection<ImportPath>): KaScopeContext {
+    val fileWithImports = buildFileWithImports(originalFile, importsToGenerate)
+
+    return fileWithImports.importingScopeContext
+}
+
+private fun buildFileWithImports(
+    originalFile: KtFile,
+    importsToGenerate: Collection<ImportPath>
+): KtFile {
+    val imports = buildString {
+        for (importPath in importsToGenerate) {
+            append("import ")
+            append(importPath)
+            append("\n")
+        }
+    }
+
+    // TODO this code fragment misses a package declaration
+    val fileWithImports  = KtBlockCodeFragment(originalFile.project, "Dummy_" + originalFile.name, "", imports, originalFile)
+
+    return fileWithImports
+}
+

plugins/kotlin/fir/tests/test/org/jetbrains/kotlin/idea/fir/imports/FirJvmOptimizeImportsTestGenerated.java

@@ -579,6 +579,11 @@ public abstract class FirJvmOptimizeImportsTestGenerated extends AbstractFirJvmO
                 runTest("../../idea/tests/testData/editor/optimizeImports/common/Enums.kt");
             }
 
+            @TestMetadata("ExplicitImportIsNotRemovedToAvoidConflict.kt")
+            public void testExplicitImportIsNotRemovedToAvoidConflict() throws Exception {
+                runTest("../../idea/tests/testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.kt");
+            }
+
             @TestMetadata("ExtensionFunWithThisReference.kt")
             public void testExtensionFunWithThisReference() throws Exception {
                 runTest("../../idea/tests/testData/editor/optimizeImports/common/ExtensionFunWithThisReference.kt");

plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/imports/JsOptimizeImportsTestGenerated.java

@@ -311,6 +311,11 @@ public abstract class JsOptimizeImportsTestGenerated extends AbstractJsOptimizeI
                 runTest("testData/editor/optimizeImports/common/Enums.kt");
             }
 
+            @TestMetadata("ExplicitImportIsNotRemovedToAvoidConflict.kt")
+            public void testExplicitImportIsNotRemovedToAvoidConflict() throws Exception {
+                runTest("testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.kt");
+            }
+
             @TestMetadata("ExtensionFunWithThisReference.kt")
             public void testExtensionFunWithThisReference() throws Exception {
                 runTest("testData/editor/optimizeImports/common/ExtensionFunWithThisReference.kt");

plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/imports/JvmOptimizeImportsTestGenerated.java

@@ -584,6 +584,11 @@ public abstract class JvmOptimizeImportsTestGenerated extends AbstractJvmOptimiz
                 runTest("testData/editor/optimizeImports/common/Enums.kt");
             }
 
+            @TestMetadata("ExplicitImportIsNotRemovedToAvoidConflict.kt")
+            public void testExplicitImportIsNotRemovedToAvoidConflict() throws Exception {
+                runTest("testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.kt");
+            }
+
             @TestMetadata("ExtensionFunWithThisReference.kt")
             public void testExtensionFunWithThisReference() throws Exception {
                 runTest("testData/editor/optimizeImports/common/ExtensionFunWithThisReference.kt");

plugins/kotlin/idea/tests/testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.dependency1.kt

@@ -0,0 +1,7 @@
+package dependencyFoo
+
+class CommonClass
+
+fun fooOne() {}
+fun fooTwo() {}
+fun fooThree() {}

plugins/kotlin/idea/tests/testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.dependency2.kt

@@ -0,0 +1,7 @@
+package dependencyBar
+
+class CommonClass
+
+fun barOne() {}
+fun barTwo() {}
+fun barThree() {}

plugins/kotlin/idea/tests/testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.kt

@@ -0,0 +1,22 @@
+// NAME_COUNT_TO_USE_STAR_IMPORT: 2
+package test
+
+import dependencyBar.*
+import dependencyFoo.*
+import dependencyFoo.CommonClass
+
+fun barUsage() {
+    barOne()
+    barTwo()
+    barThree()
+}
+
+fun fooUsage() {
+    fooOne()
+    fooTwo()
+    fooThree()
+}
+
+fun test() {
+    CommonClass()
+}

plugins/kotlin/idea/tests/testData/editor/optimizeImports/common/ExplicitImportIsNotRemovedToAvoidConflict.kt.after

@@ -0,0 +1,22 @@
+// NAME_COUNT_TO_USE_STAR_IMPORT: 2
+package test
+
+import dependencyBar.*
+import dependencyFoo.*
+import dependencyFoo.CommonClass
+
+fun barUsage() {
+    barOne()
+    barTwo()
+    barThree()
+}
+
+fun fooUsage() {
+    fooOne()
+    fooTwo()
+    fooThree()
+}
+
+fun test() {
+    CommonClass()
+}