[Workspace Model] [IJPL-14579] Do not throw rootsChanged in case the order of library roots groups has changed

The previous project model collected roots grouped by the root type. Because the order of keys doesn't exist in maps, the `iml` save sorted the groups alphabetically. And after the `iml` was loaded, this sorting didn't affect the library itself.

In case of `LibraryEntity`, the roots are stored in the flat list, so such sorting will cause `LibraryEntity` change. With an additional logic, we'll avoid an extra "roots changed" event

GitOrigin-RevId: b82823dd5b1a2a266bdda73b65ef51af6c4f5f24

platform/lang-impl/src/com/intellij/util/indexing/CustomEntitiesCausingReindexTracker.java

@@ -98,6 +98,17 @@ final class CustomEntitiesCausingReindexTracker {
              !newContentRootEntity.getExcludedPatterns().equals(oldContentRootEntity.getExcludedPatterns());
     }
 
+    // The rootsChanged is not thrown if the order of root groups has changed. Root group - group of roots collected by type.
+    //   rootsChanged is still thrown if the order of roots inside one group changes.
+    if (newEntity instanceof LibraryEntity newLibraryEntity && oldEntity instanceof LibraryEntity oldLibraryEntity) {
+      if (newLibraryEntity.getTableId().equals(oldLibraryEntity.getTableId()) &&
+          newLibraryEntity.getRoots().size() == oldLibraryEntity.getRoots().size() &&
+          newLibraryEntity.getRoots().stream().collect(Collectors.groupingBy(o -> o.getType()))
+            .equals(oldLibraryEntity.getRoots().stream().collect(Collectors.groupingBy(o -> o.getType())))) {
+        return false;
+      }
+    }
+
     WorkspaceEntity entity = newEntity != null ? newEntity : oldEntity;
 
     // `rootsChanged` should not be thrown for changes in global libraries that are not presented in a project

platform/workspace/jps/tests/testSrc/com/intellij/workspaceModel/ide/LibraryEntityWorkspaceModelTest.kt

@@ -0,0 +1,161 @@
+// Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.workspaceModel.ide
+
+import com.intellij.openapi.application.runWriteActionAndWait
+import com.intellij.openapi.roots.ModuleRootEvent
+import com.intellij.openapi.roots.ModuleRootListener
+import com.intellij.platform.backend.workspace.workspaceModel
+import com.intellij.platform.workspace.jps.entities.*
+import com.intellij.platform.workspace.storage.entities
+import com.intellij.platform.workspace.storage.testEntities.entities.MySource
+import com.intellij.testFramework.ApplicationRule
+import com.intellij.testFramework.DisposableRule
+import com.intellij.testFramework.rules.ProjectModelRule
+import com.intellij.testFramework.workspaceModel.update
+import com.intellij.testFramework.workspaceModel.updateProjectModel
+import kotlinx.coroutines.runBlocking
+import org.junit.ClassRule
+import org.junit.Rule
+import org.junit.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+
+class LibraryEntityWorkspaceModelTest {
+  companion object {
+    @ClassRule
+    @JvmField
+    val application = ApplicationRule()
+  }
+
+  @Rule
+  @JvmField
+  val projectModel = ProjectModelRule()
+
+  @Rule
+  @JvmField
+  val disposableRule = DisposableRule()
+
+  @Test
+  fun `rootsChanged is thrown when library table id changes`() = runBlocking {
+    val model = projectModel.project.workspaceModel
+    val manager = model.getVirtualFileUrlManager()
+    model.update { builder ->
+      val roots = listOf(
+        LibraryRoot(manager.getOrCreateFromUrl("/123"), LibraryRootTypeId.SOURCES),
+        LibraryRoot(manager.getOrCreateFromUrl("/321"), LibraryRootTypeId.COMPILED),
+      )
+      builder addEntity LibraryEntity("MyLib", LibraryTableId.ProjectLibraryTableId, roots, MySource)
+
+      val libraryDependency = LibraryDependency(LibraryId("MyLib", LibraryTableId.ProjectLibraryTableId), false, DependencyScope.RUNTIME)
+      builder addEntity ModuleEntity("MyModule", listOf(libraryDependency), MySource) {}
+    }
+
+    var rootsChangedCounter = 0
+    projectModel.project
+      .getMessageBus()
+      .connect(disposableRule.disposable)
+      .subscribe<ModuleRootListener>(
+        ModuleRootListener.TOPIC,
+        object : ModuleRootListener {
+          override fun rootsChanged(event: ModuleRootEvent) {
+            rootsChangedCounter += 1
+          }
+        }
+      )
+    runWriteActionAndWait {
+      model.updateProjectModel { builder ->
+        val library = builder.entities<LibraryEntity>().single()
+        builder.modifyLibraryEntity(library) {
+          this.tableId = LibraryTableId.ModuleLibraryTableId(ModuleId("MyModule"))
+        }
+      }
+    }
+
+    assertEquals(1, rootsChangedCounter)
+    assertFalse(projectModel.project.messageBus.hasUndeliveredEvents(ModuleRootListener.TOPIC))
+  }
+
+  @Test
+  fun `rootsChanged is not thrown when order of library root groups changes`() = runBlocking {
+    val model = projectModel.project.workspaceModel
+    val manager = model.getVirtualFileUrlManager()
+    model.update { builder ->
+      val roots = listOf(
+        LibraryRoot(manager.getOrCreateFromUrl("/123"), LibraryRootTypeId.SOURCES),
+        LibraryRoot(manager.getOrCreateFromUrl("/321"), LibraryRootTypeId.COMPILED),
+      )
+      builder addEntity LibraryEntity("MyLib", LibraryTableId.ProjectLibraryTableId, roots, MySource)
+
+      val libraryDependency = LibraryDependency(LibraryId("MyLib", LibraryTableId.ProjectLibraryTableId), false, DependencyScope.RUNTIME)
+      builder addEntity ModuleEntity("MyModule", listOf(libraryDependency), MySource) {}
+    }
+
+    var rootsChangedCounter = 0
+    projectModel.project
+      .getMessageBus()
+      .connect(disposableRule.disposable)
+      .subscribe<ModuleRootListener>(
+        ModuleRootListener.TOPIC,
+        object : ModuleRootListener {
+          override fun rootsChanged(event: ModuleRootEvent) {
+            rootsChangedCounter += 1
+          }
+        }
+      )
+    runWriteActionAndWait {
+      model.updateProjectModel { builder ->
+        val library = builder.entities<LibraryEntity>().single()
+        builder.modifyLibraryEntity(library) {
+          this.roots.reverse()
+        }
+      }
+    }
+
+    assertEquals(LibraryRootTypeId.COMPILED, model.currentSnapshot.entities<LibraryEntity>().single().roots.first().type)
+
+    assertEquals(0, rootsChangedCounter)
+    assertFalse(projectModel.project.messageBus.hasUndeliveredEvents(ModuleRootListener.TOPIC))
+  }
+
+  @Test
+  fun `rootsChanged is thrown when order of roots in one group changes`() = runBlocking {
+    val model = projectModel.project.workspaceModel
+    val manager = model.getVirtualFileUrlManager()
+    model.update { builder ->
+      val roots = listOf(
+        LibraryRoot(manager.getOrCreateFromUrl("/123"), LibraryRootTypeId.COMPILED),
+        LibraryRoot(manager.getOrCreateFromUrl("/321"), LibraryRootTypeId.COMPILED),
+      )
+      builder addEntity LibraryEntity("MyLib", LibraryTableId.ProjectLibraryTableId, roots, MySource)
+
+      val libraryDependency = LibraryDependency(LibraryId("MyLib", LibraryTableId.ProjectLibraryTableId), false, DependencyScope.RUNTIME)
+      builder addEntity ModuleEntity("MyModule", listOf(libraryDependency), MySource) {}
+    }
+
+    var rootsChangedCounter = 0
+    projectModel.project
+      .getMessageBus()
+      .connect(disposableRule.disposable)
+      .subscribe<ModuleRootListener>(
+        ModuleRootListener.TOPIC,
+        object : ModuleRootListener {
+          override fun rootsChanged(event: ModuleRootEvent) {
+            rootsChangedCounter += 1
+          }
+        }
+      )
+    runWriteActionAndWait {
+      model.updateProjectModel { builder ->
+        val library = builder.entities<LibraryEntity>().single()
+        builder.modifyLibraryEntity(library) {
+          this.roots.reverse()
+        }
+      }
+    }
+
+    assertEquals("/321", model.currentSnapshot.entities<LibraryEntity>().single().roots.first().url.url)
+
+    assertEquals(1, rootsChangedCounter)
+    assertFalse(projectModel.project.messageBus.hasUndeliveredEvents(ModuleRootListener.TOPIC))
+  }
+}