release: v0.2.4 里程碑快照（孤儿提交，无父；树 = dev 68362e5）

本批内容见 CHANGELOG.md 的 0.2.4 段。按 D41 用孤儿快照推 main，保留「公开史只有里程碑」的模型。

crates/core/tests/liteloader/fixtures/liteloader-versions.json

@@ -0,0 +1,98 @@
+{
+  "meta": {
+    "description": "LiteLoader is a lightweight mod bootstrap designed to provide basic loader functionality for mods which don't need to modify game mechanics.",
+    "authors": "Mumfrey",
+    "url": "http://dl.liteloader.com",
+    "updated": "2017-11-29T16:31:41+00:00",
+    "updatedTime": 1511973101
+  },
+  "versions": {
+    "1.7.10": {
+      "repo": {
+        "stream": "RELEASE",
+        "type": "ivy",
+        "url": "http://dl.liteloader.com/versions/",
+        "classifier": "mcpnames"
+      },
+      "artefacts": {
+        "com.mumfrey:liteloader": {
+          "63ada46e033d0cb6782bada09ad5ca4e": {
+            "tweakClass": "com.mumfrey.liteloader.launch.LiteLoaderTweaker",
+            "libraries": [
+              { "name": "net.minecraft:launchwrapper:1.11" },
+              { "name": "org.ow2.asm:asm-all:5.0.3" }
+            ],
+            "srcJar": "liteloader-1.7.10_04-mcpnames-sources.jar",
+            "mcpJar": "liteloader-1.7.10_04-mcpnames.jar",
+            "stream": "RELEASE",
+            "file": "liteloader-1.7.10_04.jar",
+            "version": "1.7.10_04",
+            "md5": "63ada46e033d0cb6782bada09ad5ca4e",
+            "timestamp": "1414368553"
+          },
+          "db7235aefd407ac1fde09a7baba50839": {
+            "tweakClass": "com.mumfrey.liteloader.launch.LiteLoaderTweaker",
+            "libraries": [
+              { "name": "net.minecraft:launchwrapper:1.9" },
+              {
+                "name": "org.ow2.asm:asm-all:5.0.3",
+                "url": "http://repo.maven.apache.org/maven2/"
+              }
+            ],
+            "stream": "RELEASE",
+            "file": "liteloader-1.7.10_00.jar",
+            "version": "1.7.10_00",
+            "md5": "db7235aefd407ac1fde09a7baba50839",
+            "timestamp": "1404330030"
+          }
+        }
+      }
+    },
+    "1.12.2": {
+      "repo": {
+        "stream": "SNAPSHOT",
+        "type": "m2",
+        "url": "http://repo.mumfrey.com/content/repositories/snapshots/",
+        "classifier": ""
+      },
+      "snapshots": {
+        "libraries": [
+          { "name": "net.minecraft:launchwrapper:1.12" },
+          {
+            "name": "org.spongepowered:mixin:0.7.4-SNAPSHOT",
+            "url": "https://repo.spongepowered.org/maven/"
+          }
+        ],
+        "com.mumfrey:liteloader": {
+          "1420785ecbfed5aff4a586c5c9dd97eb": {
+            "tweakClass": "com.mumfrey.liteloader.launch.LiteLoaderTweaker",
+            "libraries": [
+              { "name": "net.minecraft:launchwrapper:1.12" },
+              { "name": "org.ow2.asm:asm-all:5.2" }
+            ],
+            "stream": "SNAPSHOT",
+            "file": "liteloader-1.12.2-SNAPSHOT.jar",
+            "version": "1.12.2-SNAPSHOT",
+            "build": "1.12.2-SNAPSHOT-r4CC2BB0-b4-4",
+            "md5": "1420785ecbfed5aff4a586c5c9dd97eb",
+            "timestamp": "1511880271",
+            "lastSuccessfulBuild": 4
+          },
+          "latest": {
+            "tweakClass": "com.mumfrey.liteloader.launch.LiteLoaderTweaker",
+            "libraries": [
+              { "name": "net.minecraft:launchwrapper:1.12" },
+              { "name": "org.ow2.asm:asm-all:5.2" }
+            ],
+            "stream": "SNAPSHOT",
+            "file": "liteloader-1.12.2-SNAPSHOT.jar",
+            "version": "1.12.2-SNAPSHOT",
+            "md5": "1420785ecbfed5aff4a586c5c9dd97eb",
+            "timestamp": "1511880271",
+            "lastSuccessfulBuild": 4
+          }
+        }
+      }
+    }
+  }
+}

crates/core/tests/liteloader/guards.rs

@@ -0,0 +1,200 @@
+//! 边界与失败面：父版本缺失、组合不支持、数据源形状坏、取消。
+//!
+//! 网络层的失败映射（`DownloadError` → `loader_network`）由 `core::download` 的引擎测试
+//! 与既有加载器测试覆盖，这里**不联网**：外部源的真实可用性在 mission 报告里单独列
+//! （含探测结果），不混进单元测试冒充。
+
+use std::sync::atomic::AtomicBool;
+
+use unlucky_core::addon::loader::liteloader::parse_versions;
+use unlucky_core::addon::loader::{
+    LoaderErrorKind, LoaderInstallPlan, LoaderKind, LoaderPlanInput, LoaderSource,
+};
+use unlucky_core::download::blocking::block_on;
+use unlucky_core::game::arguments::Environment;
+use unlucky_core::game::install::{execute_with_cancel, InstallErrorKind};
+use unlucky_core::game::layout::GameLayout;
+
+use crate::support::{engine, liteloader_release, prefill, put_version, TempDir, VANILLA_1122};
+
+/// 父版本不是原版、又没装在盘上 → **具名报错**，绝不默默改成叠原版。
+#[test]
+fn missing_loader_parent_is_a_named_error() {
+    let temp = TempDir::new("missing-parent");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+    let release = liteloader_release("1.12.2-forge-14.23.5.2860");
+
+    let error = LoaderInstallPlan::build(LoaderPlanInput {
+        layout: &layout,
+        release: &release,
+        environment: &Environment::host(),
+        parent_installed: false,
+    })
+    .expect_err("父版本缺失必须报错");
+    assert_eq!(error.kind(), LoaderErrorKind::NotFound);
+    assert!(
+        error.message().contains("1.12.2-forge-14.23.5.2860"),
+        "错误里要点名缺的是哪个父版本：{}",
+        error.message()
+    );
+    assert!(error.hint().is_some(), "要给出下一步怎么办");
+}
+
+/// 父版本链：读盘定位原版版本 id（合成 loader id / 定位 jar 都用它）。
+#[test]
+fn parent_chain_walks_to_the_vanilla_root() {
+    let temp = TempDir::new("parent-chain");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+    put_version(
+        &layout,
+        "1.12.2-forge-14.23.5.2860",
+        crate::support::FORGE_1122,
+    );
+
+    assert_eq!(
+        unlucky_core::addon::loader::parent::root_version_id(&layout, "1.12.2-forge-14.23.5.2860")
+            .expect("两层链应走得到根"),
+        "1.12.2"
+    );
+    assert_eq!(
+        unlucky_core::addon::loader::parent::root_version_id(&layout, "1.12.2").expect("根是自己"),
+        "1.12.2"
+    );
+
+    // 没装的父版本 → not_found（而不是猜一个原版版本号）。
+    let error = unlucky_core::addon::loader::parent::root_version_id(&layout, "9.9.9-forge-1.0.0")
+        .expect_err("缺父版本必须报错");
+    assert_eq!(error.kind(), LoaderErrorKind::NotFound);
+}
+
+/// 只有 LiteLoader 接受「父版本不是原版」；别家**具名拒绝**，不去发请求。
+#[test]
+fn only_liteloader_accepts_a_non_vanilla_parent() {
+    let temp = TempDir::new("combo-guard");
+    let engine = engine(temp.path());
+    let source = LoaderSource::new(&engine, temp.path());
+    let error = block_on(async {
+        source
+            .resolve_on(
+                LoaderKind::Forge,
+                "1.12.2",
+                Some("14.23.5.2860"),
+                Some("1.12.2-liteloader-1.12.2-SNAPSHOT"),
+            )
+            .await
+    })
+    .expect_err("Forge 叠在 LiteLoader 上必须被拒");
+    assert_eq!(error.kind(), LoaderErrorKind::Unsupported);
+    assert!(
+        error
+            .message()
+            .contains("1.12.2-liteloader-1.12.2-SNAPSHOT"),
+        "要说清是哪个组合：{}",
+        error.message()
+    );
+}
+
+/// 版本表形状坏 / 空表：各自给具名大类，不当成「没有版本」糊过去。
+#[test]
+fn broken_version_table_is_reported_distinctly() {
+    let shape = parse_versions(r#"{"versions": []}"#).expect_err("形状不符");
+    assert_eq!(shape.kind(), LoaderErrorKind::Metadata);
+    let empty = parse_versions(r#"{"meta": {}, "versions": {}}"#).expect_err("空表");
+    assert_eq!(empty.kind(), LoaderErrorKind::NotFound);
+
+    // 版本段缺失（记录没有 version）：只剩 latest 别名 → 仍当空表处理。
+    let only_latest = r#"{"versions": {"1.7.10": {"artefacts": {"com.mumfrey:liteloader":
+        {"latest": {"tweakClass": "x", "version": "", "file": "liteloader.jar"}}}}}}"#;
+    let error = parse_versions(only_latest).expect_err("只有 http 别名时没有可用版本");
+    assert_eq!(error.kind(), LoaderErrorKind::NotFound);
+}
+
+/// 取消：执行段看标志就返回 `Cancelled`，**版本 JSON 不落盘**（不留半成品）。
+#[test]
+fn cancel_leaves_no_manifest() {
+    let temp = TempDir::new("cancel");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+    let release = liteloader_release("1.12.2");
+    let plan = LoaderInstallPlan::build(LoaderPlanInput {
+        layout: &layout,
+        release: &release,
+        environment: &Environment::host(),
+        parent_installed: true,
+    })
+    .expect("计划应可组");
+
+    let engine = engine(temp.path());
+    prefill(&plan.install);
+    let cancel = AtomicBool::new(true);
+    let error = block_on(execute_with_cancel(
+        &engine,
+        &plan.install,
+        4,
+        None,
+        Some(&cancel),
+    ))
+    .expect_err("取消必须返回错误");
+    assert_eq!(error.kind(), InstallErrorKind::Cancelled);
+    assert!(
+        !layout.version_json(&release.version_id).exists(),
+        "取消之后不许留下版本清单"
+    );
+}
+
+/// 同一个 loader 版本 id 被两条父链请求：**具名报错**，且盘上那份清单一个字节都不动。
+///
+/// 为什么必须有这道门：`<原版>-liteloader-<ver>` 对「叠原版」与「叠 Forge」是同一个目录名，
+/// 直接覆盖会让已经登记、指向这个版本 id 的旧实例**静默换父链**（启动行为跟着变）。
+#[test]
+fn parent_collision_is_refused_instead_of_overwriting() {
+    let temp = TempDir::new("parent-collision");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+    put_version(
+        &layout,
+        "1.12.2-forge-14.23.5.2860",
+        crate::support::FORGE_1122,
+    );
+
+    let vanilla_release = liteloader_release("1.12.2");
+    let existing = serde_json::json!({
+        "id": vanilla_release.version_id,
+        "inheritsFrom": "1.12.2",
+        "mainClass": "net.minecraft.launchwrapper.Launch",
+        "arguments": {"game": ["--tweakClass", "com.mumfrey.liteloader.launch.LiteLoaderTweaker"]},
+        "libraries": []
+    });
+    put_version(
+        &layout,
+        &vanilla_release.version_id,
+        &serde_json::to_string_pretty(&existing).expect("序列化"),
+    );
+    let before = std::fs::read_to_string(layout.version_json(&vanilla_release.version_id))
+        .expect("读旧清单");
+
+    let forge_release = liteloader_release("1.12.2-forge-14.23.5.2860");
+    assert_eq!(
+        forge_release.version_id, vanilla_release.version_id,
+        "两条父链撞同一个 id"
+    );
+    let error = LoaderInstallPlan::build(LoaderPlanInput {
+        layout: &layout,
+        release: &forge_release,
+        environment: &Environment::host(),
+        parent_installed: true,
+    })
+    .expect_err("撞父链必须报错");
+    assert_eq!(error.kind(), LoaderErrorKind::Unsupported);
+    assert!(
+        error.message().contains("1.12.2-forge-14.23.5.2860") && error.message().contains("1.12.2"),
+        "要说清两条父链各是什么：{}",
+        error.message()
+    );
+
+    let after = std::fs::read_to_string(layout.version_json(&vanilla_release.version_id))
+        .expect("读旧清单");
+    assert_eq!(before, after, "报错之后盘上那份清单不许被改动");
+}

crates/core/tests/liteloader/install.rs

@@ -0,0 +1,297 @@
+//! 解析 → 计划 → 落盘 → 继承解析 → 启动参数顺序（两条父链：原版 / Forge）。
+
+use unlucky_core::addon::loader::{LoaderInstallPlan, LoaderPlanInput};
+use unlucky_core::download::blocking::block_on;
+use unlucky_core::game::arguments::Environment;
+use unlucky_core::game::inherit::resolve;
+use unlucky_core::game::install::execute;
+use unlucky_core::game::layout::GameLayout;
+use unlucky_core::launch::command_builder::tokenize;
+
+use crate::support::{
+    engine, liteloader_release, prefill, put_version, read_version, TempDir, FORGE_1122,
+    VANILLA_1122,
+};
+
+/// 原版父链：装完能落盘，清单指向原版，`arguments.game` 带 tweakClass。
+#[test]
+fn installs_over_vanilla_and_writes_the_manifest() {
+    let temp = TempDir::new("vanilla");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+
+    let release = liteloader_release("1.12.2");
+    assert_eq!(release.version_id, "1.12.2-liteloader-1.12.2-SNAPSHOT");
+    let plan = LoaderInstallPlan::build(LoaderPlanInput {
+        layout: &layout,
+        release: &release,
+        environment: &Environment::host(),
+        parent_installed: true,
+    })
+    .expect("父版本已装，计划应可组");
+    assert!(!plan.vanilla_install_needed);
+    assert!(plan.install.client_jar().is_none(), "jar 归原版层");
+
+    // 三个库：launchwrapper（Mojang 库仓）+ asm-all（Central）+ 本体 jar（官方直链）。
+    let names: Vec<&str> = plan.files().iter().map(|file| file.name.as_str()).collect();
+    assert_eq!(names.len(), 3, "{names:?}");
+    let loader_jar = plan
+        .files()
+        .iter()
+        .find(|file| file.name == "com.mumfrey:liteloader:1.12.2-SNAPSHOT")
+        .expect("缺本体 jar");
+    assert!(
+        loader_jar
+            .url
+            .ends_with("/1.12.2-SNAPSHOT/liteloader-1.12.2-20171128.144431-4-release.jar"),
+        "本体直链：{}",
+        loader_jar.url
+    );
+    let asm = plan
+        .files()
+        .iter()
+        .find(|file| file.name.contains("asm-all"))
+        .expect("缺 asm-all");
+    assert!(
+        asm.url.starts_with("https://repo1.maven.org/maven2/"),
+        "asm-all 只能从 Central 取：{}",
+        asm.url
+    );
+
+    // 全部落点先铺好占位文件（库无 sha1/size → 存在即信），执行段只写版本 JSON。
+    let engine = engine(temp.path());
+    let prefilled = prefill(&plan.install);
+    assert_eq!(prefilled, 3);
+    let report = block_on(execute(&engine, &plan.install, 4, None)).expect("执行应成功");
+    assert!(report.is_complete(), "{:?}", report.failures(3));
+
+    let written = read_version(&layout, &release.version_id);
+    assert_eq!(written.inherits_from.as_deref(), Some("1.12.2"));
+    assert_eq!(
+        written.main_class.as_deref(),
+        Some("net.minecraft.launchwrapper.Launch")
+    );
+    assert!(
+        written.minecraft_arguments.is_none(),
+        "loader 层不许写 minecraftArguments：那会顶掉父链"
+    );
+}
+
+/// Forge 父链：**父链的 FMLTweaker 必须还在**，LiteLoader 的 tweakClass 追加在它后面。
+///
+/// 这条是 M218 SURVEY-p1 的「准入条件」：靠 `--tweakClass` 生效，就要求继承时
+/// `arguments.game` 是追加、`minecraftArguments` 不被子层覆盖。启动参数顺序照
+/// `core::launch::game_args` 的第 24 项（legacy 子串）→ 第 25 项（`arguments.game`）复现，
+/// 真实 argv 由 `tests/launch/cmdline_snapshot.rs` 钉住。
+#[test]
+fn stacks_on_forge_and_keeps_the_forge_tweak_class() {
+    let temp = TempDir::new("forge");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+    put_version(&layout, "1.12.2-forge-14.23.5.2860", FORGE_1122);
+
+    let release = liteloader_release("1.12.2-forge-14.23.5.2860");
+    assert!(!release.parent_is_vanilla());
+    let plan = LoaderInstallPlan::build(LoaderPlanInput {
+        layout: &layout,
+        release: &release,
+        environment: &Environment::host(),
+        parent_installed: true,
+    })
+    .expect("父版本已装，计划应可组");
+    assert_eq!(plan.install.jar_id, "1.12.2", "jar 仍取原版那层");
+
+    let engine = engine(temp.path());
+    prefill(&plan.install);
+    let report = block_on(execute(&engine, &plan.install, 4, None)).expect("执行应成功");
+    assert!(report.is_complete(), "{:?}", report.failures(3));
+
+    let installed = read_version(&layout, &release.version_id);
+    let mut source = std::collections::BTreeMap::new();
+    source.insert("1.12.2".to_string(), read_version(&layout, "1.12.2"));
+    source.insert(
+        "1.12.2-forge-14.23.5.2860".to_string(),
+        read_version(&layout, "1.12.2-forge-14.23.5.2860"),
+    );
+    source.insert(release.version_id.clone(), installed);
+    let resolved = resolve(&source, &source[&release.version_id]).expect("三层继承应可解析");
+
+    // ① 父链的 legacy 参数整串还在（子层没写 minecraftArguments）。
+    let legacy = resolved
+        .minecraft_arguments
+        .as_deref()
+        .expect("Forge 的 minecraftArguments 不许被子层顶掉");
+    assert!(
+        legacy.contains("net.minecraftforge.fml.common.launcher.FMLTweaker"),
+        "Forge 的 tweakClass 丢了：{legacy}"
+    );
+
+    // ② 启动顺序：legacy（第 24 项）在前，arguments.game（第 25 项）在后。
+    let mut game: Vec<String> = tokenize(legacy);
+    game.extend(
+        resolved
+            .arguments
+            .as_ref()
+            .expect("arguments 应保留")
+            .expand(&Environment::host())
+            .game,
+    );
+    let forge_at = game
+        .iter()
+        .position(|token| token.contains("FMLTweaker"))
+        .expect("Forge tweakClass 不在游戏参数里");
+    let liteloader_at = game
+        .iter()
+        .position(|token| token == "com.mumfrey.liteloader.launch.LiteLoaderTweaker")
+        .expect("LiteLoader tweakClass 不在游戏参数里");
+    assert!(
+        forge_at < liteloader_at,
+        "launchwrapper 按出现顺序应用 tweak：Forge 必须在前，实际 {game:?}"
+    );
+    assert_eq!(game[liteloader_at - 1], "--tweakClass");
+
+    // ③ 主类与库顺序：Forge 的库在前（classpath 先到先得），LiteLoader 的在后。
+    assert_eq!(
+        resolved.main_class.as_deref(),
+        Some("net.minecraft.launchwrapper.Launch")
+    );
+    let libraries: Vec<&str> = resolved
+        .libraries
+        .as_deref()
+        .expect("libraries")
+        .iter()
+        .map(|library| library.name.as_str())
+        .collect();
+    let forge_lib = libraries
+        .iter()
+        .position(|name| name.starts_with("net.minecraftforge:forge:"))
+        .expect("缺 Forge 本体库");
+    let liteloader_lib = libraries
+        .iter()
+        .position(|name| name.starts_with("com.mumfrey:liteloader:"))
+        .expect("缺 LiteLoader 本体库");
+    assert!(forge_lib < liteloader_lib, "{libraries:?}");
+}
+
+/// **新式 args 的父链**：父版本用 `arguments.game`（没有 `minecraftArguments`）。
+///
+/// 现实里 LiteLoader 只到 1.12.2，碰不到这种父版本；但「追加语义」是这套路线的准入条件，
+/// 两种父版本形状都得钉住——否则哪天上游把老版本清单改成新式，我们会静默丢参数。
+/// 这里用一份**手工夹具**（`--launchTarget forgeclient` 是 Forge 1.13+ 的真实形态）说明：
+/// 父层参数在前、LiteLoader 的 tweakClass 在后，中间不互相覆盖。
+#[test]
+fn new_style_parent_args_are_appended_not_replaced() {
+    const MODERN_PARENT: &str = r#"{
+      "id": "1.12.2-modern-1.0",
+      "inheritsFrom": "1.12.2",
+      "mainClass": "net.minecraft.launchwrapper.Launch",
+      "arguments": {"game": ["--launchTarget", "forgeclient"], "jvm": ["-Dmodern=1"]},
+      "libraries": [{"name": "example:modern:1.0", "url": "https://example.invalid/"}]
+    }"#;
+
+    let temp = TempDir::new("modern-args");
+    let layout = GameLayout::new(temp.path());
+    put_version(&layout, "1.12.2", VANILLA_1122);
+    put_version(&layout, "1.12.2-modern-1.0", MODERN_PARENT);
+
+    let release = liteloader_release("1.12.2-modern-1.0");
+    let plan = LoaderInstallPlan::build(LoaderPlanInput {
+        layout: &layout,
+        release: &release,
+        environment: &Environment::host(),
+        parent_installed: true,
+    })
+    .expect("计划应可组");
+    let engine = engine(temp.path());
+    prefill(&plan.install);
+    let report = block_on(execute(&engine, &plan.install, 4, None)).expect("执行应成功");
+    assert!(report.is_complete(), "{:?}", report.failures(3));
+
+    let mut source = std::collections::BTreeMap::new();
+    source.insert("1.12.2".to_string(), read_version(&layout, "1.12.2"));
+    source.insert(
+        "1.12.2-modern-1.0".to_string(),
+        read_version(&layout, "1.12.2-modern-1.0"),
+    );
+    source.insert(
+        release.version_id.clone(),
+        read_version(&layout, &release.version_id),
+    );
+    let resolved = resolve(&source, &source[&release.version_id]).expect("三层继承应可解析");
+
+    // 子层没写 legacy 串：继承结果里的 `minecraftArguments` 只能是祖父层（原版）那一份，
+    // 里面绝不能出现 LiteLoader 的 tweakClass（写了就说明我们用了覆盖语义）。
+    let legacy = resolved
+        .minecraft_arguments
+        .as_deref()
+        .expect("原版那份 legacy 串应沿链继承下来");
+    assert!(
+        !legacy.contains("LiteLoaderTweaker"),
+        "loader 层不许往 minecraftArguments 里写：{legacy}"
+    );
+    let game = resolved
+        .arguments
+        .as_ref()
+        .expect("arguments")
+        .expand(&Environment::host())
+        .game;
+    let assert_order = |needle: &str| {
+        game.iter()
+            .position(|token| token == needle)
+            .unwrap_or_else(|| panic!("缺 `{needle}`：{game:?}"))
+    };
+    assert!(
+        assert_order("forgeclient")
+            < assert_order("com.mumfrey.liteloader.launch.LiteLoaderTweaker"),
+        "父层参数必须在前：{game:?}"
+    );
+}
+
+/// LiteLoader 生效所依赖的**两条继承合并律**（M222 第一步核实，直接钉在合并函数上）。
+///
+/// 1. `arguments.game`：父在前、子在后**追加**（所以 tweakClass 能叠在父链参数之后）；
+/// 2. `minecraftArguments`：**子覆盖父**（所以 loader 层绝不能写它，否则父链的 tweakClass
+///    整串消失）。
+///
+/// 抓得住：有人把 `minecraftArguments` 改成追加（HMCL/原版语义不是这样），或把
+/// `arguments.game` 改成整体替换（LiteLoader/其它叠层加载器当场失效）。
+/// 抓不住：真实启动 argv 的顺序（那是 `launch::game_args` 的第 24/25 项，
+/// 由 `tests/launch/cmdline_snapshot.rs` 钉住；本 mission 没有改那一层）。
+#[test]
+fn merge_laws_liteloader_depends_on() {
+    use unlucky_core::game::inherit::merge;
+    use unlucky_core::game::manifest::VersionJson;
+
+    let parse = |json: &str| VersionJson::from_json_str(json).expect("夹具应可解析");
+
+    let parent = parse(
+        r#"{"id":"p","minecraftArguments":"--tweakClass FMLTweaker","arguments":{"game":["--parent"]}}"#,
+    );
+    let child = parse(r#"{"id":"c","arguments":{"game":["--child"]}}"#);
+    let merged = merge(&child, &parent);
+    assert_eq!(
+        merged.minecraft_arguments.as_deref(),
+        Some("--tweakClass FMLTweaker"),
+        "子没写就继承父（这条是「叠在 Forge 上」的前提）"
+    );
+    let game: Vec<String> = merged
+        .arguments
+        .as_ref()
+        .expect("arguments")
+        .expand(&Environment::host())
+        .game;
+    assert_eq!(
+        game,
+        ["--parent", "--child"],
+        "arguments.game 是父在前、子在后追加"
+    );
+
+    // 子写了 minecraftArguments：整串替换（不是追加）。
+    let loud_child = parse(r#"{"id":"c2","minecraftArguments":"--tweakClass LiteLoaderTweaker"}"#);
+    let merged = merge(&loud_child, &parent);
+    assert_eq!(
+        merged.minecraft_arguments.as_deref(),
+        Some("--tweakClass LiteLoaderTweaker"),
+        "子覆盖父：这正是 loader 层不许写 minecraftArguments 的原因"
+    );
+}

crates/core/tests/liteloader/main.rs

@@ -0,0 +1,20 @@
+//! LiteLoader 安装链路的集成测试（`tests/liteloader*` 这个 test target 的入口）。
+//!
+//! 判据链：**真实元数据夹具 → 解析 → 合成清单 → 计划 → 落盘 → 继承解析 → 启动参数顺序**。
+//! 全程不联网：LiteLoader 的库没有 sha1/size，`execute` 的跳过判据是「存在即信」，
+//! 所以先把每个待下文件按计划里的落点写一份占位字节，执行期就只做「跳过 + 写版本 JSON」。
+//!
+//! 夹具来源（可追溯）：
+//! - `fixtures/liteloader-versions.json` = 2026-11 从 `https://dl.liteloader.com/versions/versions.json`
+//!   真取的响应（200 / 49129 字节 / 16 个原版版本）裁剪到两个原版版本，**字段名与嵌套结构原样**；
+//! - `metadata.xml` = 同一次探测里 `repo.mumfrey.com/…/liteloader/1.12.2-SNAPSHOT/maven-metadata.xml`
+//!   的原样响应（200 / 358 字节）；
+//! - 原版 / Forge 1.12.2 的版本 JSON 是按官方清单形状写的最小夹具（Forge 那侧的
+//!   `minecraftArguments` 与 `crates/core/src/addon/loader/tests/forge.rs` 的实测夹具一致）。
+//!
+//! 未覆盖（如实留档）：真实下载（走 `core::download` 引擎的镜像/退避，已有 M13 的单测覆盖）、
+//! 真实 MC 启动、`dl.liteloader.com` / `repo.mumfrey.com` 的持续可用性。
+
+mod guards;
+mod install;
+mod support;

crates/core/tests/liteloader/support.rs

@@ -0,0 +1,157 @@
+//! 集成测试公用件：临时游戏目录、离线下载引擎、元数据夹具、父版本清单夹具。
+
+#![allow(dead_code)]
+
+use std::path::{Path, PathBuf};
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::sync::Arc;
+use std::time::Duration;
+
+use unlucky_core::addon::loader::liteloader::{self, LiteLoaderEntry};
+use unlucky_core::addon::loader::LoaderRelease;
+use unlucky_core::download::backoff::BackoffPolicy;
+use unlucky_core::download::cache::ContentCache;
+use unlucky_core::download::chunked::ChunkedConfig;
+use unlucky_core::download::config::EngineConfig;
+use unlucky_core::download::engine::DownloadEngine;
+use unlucky_core::download::health::HealthRegistry;
+use unlucky_core::download::mirrors::MirrorTable;
+use unlucky_core::download::region::RegionProfile;
+use unlucky_core::game::layout::GameLayout;
+use unlucky_core::game::manifest::VersionJson;
+
+/// 真实响应的裁剪版（见 `tests/liteloader.rs` 文件头的来源说明）。
+pub const VERSION_TABLE: &str = include_str!("fixtures/liteloader-versions.json");
+
+/// 1.12.2-SNAPSHOT 的 maven-metadata（真实响应原样）。
+pub const METADATA_XML: &str = r#"<?xml version="1.0" encoding="UTF-8"?>
+<metadata>
+  <groupId>com.mumfrey</groupId>
+  <artifactId>liteloader</artifactId>
+  <version>1.12.2-SNAPSHOT</version>
+  <versioning>
+    <snapshot>
+      <timestamp>20171128.144431</timestamp>
+      <buildNumber>4</buildNumber>
+    </snapshot>
+    <lastUpdated>20171128144431</lastUpdated>
+  </versioning>
+</metadata>"#;
+
+/// 原版 1.12.2（老式 `minecraftArguments`，与官方清单同形）。
+pub const VANILLA_1122: &str = r#"{
+  "id": "1.12.2",
+  "type": "release",
+  "mainClass": "net.minecraft.client.main.Main",
+  "assets": "1.12",
+  "assetIndex": {"id": "1.12"},
+  "minecraftArguments": "--username ${auth_player_name} --version ${version_name}",
+  "libraries": [
+    {"name": "com.mojang:patchy:1.1", "url": "https://libraries.minecraft.net/"}
+  ]
+}"#;
+
+/// Forge 1.12.2-14.23.5.2860（spec-0 的 version.json：主类 launchwrapper + FMLTweaker）。
+pub const FORGE_1122: &str = r#"{
+  "id": "1.12.2-forge-14.23.5.2860",
+  "inheritsFrom": "1.12.2",
+  "mainClass": "net.minecraft.launchwrapper.Launch",
+  "minecraftArguments": "--tweakClass net.minecraftforge.fml.common.launcher.FMLTweaker",
+  "libraries": [
+    {"name": "net.minecraftforge:forge:1.12.2-14.23.5.2860", "url": "https://maven.minecraftforge.net/"}
+  ]
+}"#;
+
+/// 唯一临时目录守卫（`drop` 时递归删除）。
+pub struct TempDir {
+    path: PathBuf,
+}
+
+impl TempDir {
+    pub fn new(tag: &str) -> Self {
+        static COUNTER: AtomicUsize = AtomicUsize::new(0);
+        let unique = COUNTER.fetch_add(1, Ordering::Relaxed);
+        let stamp = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .map_or(0, |since| since.as_nanos());
+        let path = std::env::temp_dir().join(format!(
+            "ull-liteloader-{tag}-{}-{stamp}-{unique}",
+            std::process::id()
+        ));
+        let _ = std::fs::remove_dir_all(&path);
+        std::fs::create_dir_all(&path).expect("临时目录应可创建");
+        Self { path }
+    }
+
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+}
+
+impl Drop for TempDir {
+    fn drop(&mut self) {
+        let _ = std::fs::remove_dir_all(&self.path);
+    }
+}
+
+/// 离线引擎：单次尝试、短超时、分块关闭（测试里只用来跑「全部跳过」的执行段）。
+pub fn engine(cache_root: &Path) -> DownloadEngine {
+    let config = EngineConfig {
+        max_attempts_per_source: 1,
+        backoff: BackoffPolicy {
+            base_ms: 1,
+            max_ms: 2,
+            jitter_ratio: 0.0,
+            max_attempts: 1,
+        },
+        connect_timeout: Duration::from_secs(3),
+        read_timeout: Duration::from_secs(3),
+        chunked: ChunkedConfig::disabled(),
+        ..EngineConfig::default()
+    };
+    DownloadEngine::new(
+        config,
+        Arc::new(MirrorTable::builtin()),
+        Arc::new(RegionProfile::direct(0)),
+        Arc::new(HealthRegistry::in_memory()),
+        Arc::new(ContentCache::open(cache_root.join("cache"))),
+    )
+}
+
+/// 解析夹具表里某个原版版本的条目。
+pub fn entries(mc_version: &str) -> Vec<LiteLoaderEntry> {
+    let table = liteloader::parse_versions(VERSION_TABLE).expect("夹具版本表应可解析");
+    table.get(mc_version).cloned().unwrap_or_default()
+}
+
+/// 取 1.12.2 的 SNAPSHOT 条目并合成 release（父版本由调用方给）。
+pub fn liteloader_release(parent_version_id: &str) -> LoaderRelease {
+    let entries = entries("1.12.2");
+    let entry = liteloader::default_entry(&entries).expect("1.12.2 应有一条版本");
+    let url = liteloader::snapshot_artifact_url(entry, METADATA_XML).expect("快照直链");
+    liteloader::build_release("1.12.2", parent_version_id, entry, &url).expect("合成清单")
+}
+
+/// 把一份版本 JSON 写进 `versions/<id>/<id>.json`（模拟「父版本已装好」）。
+pub fn put_version(layout: &GameLayout, id: &str, json: &str) {
+    let path = layout.version_json(id);
+    std::fs::create_dir_all(path.parent().expect("版本目录")).expect("建版本目录");
+    std::fs::write(&path, json).expect("写版本 JSON");
+}
+
+/// 读盘上的版本 JSON。
+pub fn read_version(layout: &GameLayout, id: &str) -> VersionJson {
+    let path = layout.version_json(id);
+    let text = std::fs::read_to_string(&path)
+        .unwrap_or_else(|error| panic!("读不到 {}：{error}", path.display()));
+    VersionJson::from_json_str(&text).expect("版本 JSON 应可解析")
+}
+
+/// 按计划把每个待下文件写成占位字节（`execute` 的跳过判据 = 无 sha1 且存在即信）。
+pub fn prefill(plan: &unlucky_core::game::install::InstallPlan) -> usize {
+    for file in &plan.files {
+        std::fs::create_dir_all(file.dest.parent().expect("文件父目录")).expect("建库目录");
+        std::fs::write(&file.dest, b"placeholder").expect("写占位文件");
+    }
+    plan.files.len()
+}