Fix #6320: 修复安装新实例时，Fabric API 安装路径未遵循版本隔离策略的问题

HMCL/src/main/java/org/jackhuang/hmcl/game/HMCLGameRepository.java

@@ -242,6 +242,19 @@ public void clean(String id) throws IOException {
         clean(getRunDirectory(id));
     }
 
+    /// Removes a version from disk and drops any cached instance settings for that version.
+    @Override
+    public boolean removeVersionFromDisk(String id) {
+        boolean removed = super.removeVersionFromDisk(id);
+        if (removed) {
+            instanceGameSettings.remove(id);
+            loadedInstanceGameSettings.remove(id);
+            readOnlyInstanceGameSettings.remove(id);
+            beingModpackVersions.remove(id);
+        }
+        return removed;
+    }
+
     public void duplicateVersion(String srcId, String dstId, boolean copySaves) throws IOException {
         Path srcDir = getVersionRoot(srcId);
         Path dstDir = getVersionRoot(dstId);
@@ -520,31 +533,35 @@ public GameSettings.Preset getParentGameSettings(@Nullable GameSettings.Instance
         return parentSetting != null ? parentSetting : SettingsManager.getDefaultGameSettingsPresetOrCreate();
     }
 
-    public GameSettings.Effective getEffectiveGameSettings(String id) {
-        GameSettings.Instance instance = getInstanceGameSettings(id);
-        return GameSettings.resolve(getParentGameSettings(instance), instance);
-    }
-
-    public void applyDefaultIsolationSetting(String id) {
-        if (!hasVersion(id)) {
-            return;
-        }
-
-        GameSettings.Instance instanceSetting = getInstanceGameSettings(id);
-        GameSettings.Preset preset = getParentGameSettings(instanceSetting);
+    /// Returns whether a new instance should use an isolated running directory under the default isolation settings.
+    public boolean shouldIsolateNewInstance(boolean modded) {
+        GameSettings.Preset preset = getParentGameSettings(null);
         DefaultIsolationType type = Lang.requireNonNullElse(preset.defaultIsolationTypeProperty().getValue(), DefaultIsolationType.MODDED);
-        boolean isolated = switch (type) {
+        return switch (type) {
             case NEVER -> false;
             case ALWAYS -> true;
-            case MODDED -> LibraryAnalyzer.isModded(this, getVersion(id).resolve(this));
+            case MODDED -> modded;
         };
+    }
 
-        if (isolated) {
-            GameSettings.Instance setting = instanceSetting != null ? instanceSetting : getInstanceGameSettingsOrCreate(id);
-            if (setting != null) {
-                setting.getOverrideProperties().add(GameSettings.PROPERTY_RUNNING_DIRECTORY);
-            }
+    /// Applies default isolation to a new instance before the version metadata is saved.
+    public void applyDefaultIsolationSettingForNewInstance(String id, boolean modded) {
+        if (!shouldIsolateNewInstance(modded) || readOnlyInstanceGameSettings.contains(id)) {
+            return;
+        }
+
+        GameSettings.Instance setting = getInstanceGameSettings(id);
+        if (setting == null) {
+            setting = initInstanceGameSettings(id, new GameSettings.Instance());
         }
+        if (setting.getOverrideProperties().add(GameSettings.PROPERTY_RUNNING_DIRECTORY)) {
+            saveGameSettings(id);
+        }
+    }
+
+    public GameSettings.Effective getEffectiveGameSettings(String id) {
+        GameSettings.Instance instance = getInstanceGameSettings(id);
+        return GameSettings.resolve(getParentGameSettings(instance), instance);
     }
 
     public Optional<Path> getVersionIconFile(String id) {

HMCL/src/main/java/org/jackhuang/hmcl/ui/download/DownloadPage.java

@@ -318,9 +318,9 @@ private Task<Void> finishVersionDownloadingAsync(SettingsMap settings) {
                     builder.version(remoteVersion);
             });
 
+            repository.applyDefaultIsolationSettingForNewInstance(name, settings.isInstallingModdedVersion());
             return builder.buildAsync().whenComplete(any -> {
                 repository.refreshVersions();
-                repository.applyDefaultIsolationSetting(name);
             }).thenRunAsync(Schedulers.javafx(), () -> repository.setSelectedInstance(name));
         }
 

HMCL/src/main/java/org/jackhuang/hmcl/ui/download/VanillaInstallWizardProvider.java

@@ -61,9 +61,9 @@ private Task<Void> finishVersionDownloadingAsync(SettingsMap settings) {
                 builder.version(remoteVersion);
         });
 
+        repository.applyDefaultIsolationSettingForNewInstance(name, settings.isInstallingModdedVersion());
         return builder.buildAsync().whenComplete(any -> {
             repository.refreshVersions();
-            repository.applyDefaultIsolationSetting(name);
         })
                 .thenRunAsync(Schedulers.javafx(), () -> repository.setSelectedInstance(name));
     }

HMCL/src/test/java/org/jackhuang/hmcl/setting/GameDirectoriesTest.java

@@ -408,6 +408,44 @@ public void repositoryDirectoryFollowsGameDirectoryPath() throws ReflectiveOpera
         }
     }
 
+    /// Tests that new isolated installing instances resolve content directories under the version root before metadata is saved.
+    @Test
+    public void newIsolatedInstallingInstanceUsesVersionRootBeforeVersionExists(@TempDir Path tempDirectory)
+            throws ReflectiveOperationException {
+        GameSettingsPresetID defaultPresetId =
+                GameSettingsPresetID.parse("game-settings-preset:123e4567-e89b-12d3-a456-426614174002");
+        GameSettings.Preset defaultPreset = new GameSettings.Preset(defaultPresetId);
+        defaultPreset.defaultIsolationTypeProperty().setValue(DefaultIsolationType.MODDED);
+        GameSettingsPresets presets = new GameSettingsPresets();
+        presets.getPresets().setAll(defaultPreset);
+
+        GameDirectory gameDirectory = new GameDirectory(
+                GameDirectoryID.generate(),
+                LocalizedText.plain("Dev"),
+                PortablePath.of(tempDirectory.toString()));
+        GameDirectories localDirectories = new GameDirectories();
+        localDirectories.getGameDirectories().add(gameDirectory);
+        GameDirectories userDirectories = new GameDirectories();
+
+        try (GameDirectoryEnvironment ignored =
+                     new GameDirectoryEnvironment(localDirectories, userDirectories, presets)) {
+            settings().defaultGameSettingsPresetProperty().set(defaultPresetId);
+            HMCLGameRepository repository = new HMCLGameRepository(gameDirectory);
+            String id = "1.21.11-fabric";
+
+            assertFalse(repository.hasVersion(id));
+            assertEquals(repository.getBaseDirectory(), repository.getRunDirectory(id));
+
+            repository.applyDefaultIsolationSettingForNewInstance(id, true);
+
+            assertEquals(repository.getVersionRoot(id), repository.getRunDirectory(id));
+            assertEquals(repository.getVersionRoot(id).resolve("mods"), repository.getModsDirectory(id));
+
+            assertTrue(repository.removeVersionFromDisk(id));
+            assertEquals(repository.getBaseDirectory(), repository.getRunDirectory(id));
+        }
+    }
+
     /// Tests that instance settings without an explicit parent use the default preset.
     @Test
     public void nullInstanceParentUsesDefaultPresetInsteadOfLegacyGameDirectoryPreset()

HMCLCore/src/main/java/org/jackhuang/hmcl/game/DefaultGameRepository.java

@@ -233,7 +233,7 @@ public boolean renameVersion(String from, String to) {
     public boolean removeVersionFromDisk(String id) {
         if (EventBus.EVENT_BUS.fireEvent(new RemoveVersionEvent(this, id)) == Event.Result.DENY)
             return false;
-        if (!versions.containsKey(id))
+        if (versions == null || !versions.containsKey(id))
             return FileUtils.deleteDirectoryQuietly(getVersionRoot(id));
         Path file = getVersionRoot(id);
         if (Files.notExists(file))

HMCLCore/src/main/java/org/jackhuang/hmcl/util/SettingsMap.java

@@ -17,6 +17,8 @@
  */
 package org.jackhuang.hmcl.util;
 
+import org.jackhuang.hmcl.download.LibraryAnalyzer;
+import org.jackhuang.hmcl.download.RemoteVersion;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -25,7 +27,7 @@
 
 /// A wrapper for `Map<String, Object>`, supporting type-safe reading and writing of values.
 ///
-///  @author Glavo
+/// @author Glavo
 public final class SettingsMap {
     public record Key<T>(String key) {
     }
@@ -87,6 +89,19 @@ public void clear() {
         map.clear();
     }
 
+    /// Returns whether the selected installation includes any non-vanilla component.
+    public boolean isInstallingModdedVersion() {
+        for (LibraryAnalyzer.LibraryType value : LibraryAnalyzer.LibraryType.values()) {
+            if (value != LibraryAnalyzer.LibraryType.MINECRAFT
+                    && value.isModLoader()
+                    && get(value.getPatchId()) instanceof RemoteVersion) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     @Override
     public String toString() {
         return "SettingsMap" + map;

HMCLCore/src/test/java/org/jackhuang/hmcl/util/SettingsMapTest.java

@@ -0,0 +1,57 @@
+/*
+ * Hello Minecraft! Launcher
+ * Copyright (C) 2026 huangyuhui <huanghongxun2008@126.com> and contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package org.jackhuang.hmcl.util;
+
+import org.jackhuang.hmcl.download.LibraryAnalyzer;
+import org.jackhuang.hmcl.download.RemoteVersion;
+import org.jetbrains.annotations.NotNullByDefault;
+import org.junit.jupiter.api.Test;
+
+import java.time.Instant;
+import java.util.List;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/// Tests for installer state stored in [SettingsMap].
+@NotNullByDefault
+public final class SettingsMapTest {
+    /// Tests that vanilla game selection alone is not treated as a modded installation.
+    @Test
+    public void minecraftSelectionIsNotModdedInstallation() {
+        SettingsMap settings = new SettingsMap();
+        settings.put(LibraryAnalyzer.LibraryType.MINECRAFT.getPatchId(), remoteVersion("game"));
+
+        assertFalse(settings.isInstallingModdedVersion());
+    }
+
+    /// Tests that selecting a non-vanilla installer is treated as a modded installation.
+    @Test
+    public void modLoaderSelectionIsModdedInstallation() {
+        SettingsMap settings = new SettingsMap();
+        settings.put(LibraryAnalyzer.LibraryType.MINECRAFT.getPatchId(), remoteVersion("game"));
+        settings.put(LibraryAnalyzer.LibraryType.FABRIC.getPatchId(), remoteVersion("fabric"));
+
+        assertTrue(settings.isInstallingModdedVersion());
+    }
+
+    /// Creates a minimal remote version for installer state tests.
+    private static RemoteVersion remoteVersion(String libraryId) {
+        return new RemoteVersion(libraryId, "1.21.11", "test", Instant.EPOCH, List.of());
+    }
+}