Merge branch 'feat/p3-forge-neoforge-gui-install-via-proces'

P2-1：wizard.slint 的 Forge/NeoForge 提示还写着「需要 installer processors：本轮请用 ull install」，
改成「需要 installer processors（首装会外调 java，约 1–3 分钟）」；全仓再扫一遍
「ull install / 显式拒装 / 终端跑」等措辞，user-facing 文案已无残留（余下命中全是
OptiFine/LiteLoader 的正确说明与测试注释）。

P2-2：进度条在处理器依赖库下完那一刻就满格（36/36），随后加载器库的 29 个文件才被计入
→ 100% 回落再涨回，且 bytes_total 用 .max() 与文件数对不上。
- Meter 新增 expect(files, bytes)：文件数与字节都 saturating_add；
- install_loader 在处理器段之前就把加载器库的文件/字节一次预记账（两段之和），
  加载器库阶段只剩切阶段文案，不再记账；
- Reporter::expect 改为委托 Meter::expect，处理器依赖库沿用同一条曲线；
- 回归测试钉住：预记账后 files_total=95、bytes_total=17MB、ratio 不再满格，
  处理器库下完仍是中间态，加载器库下完才到 100%。

真机重截 + 识图：D:/tmp/ull-m45-shots/forge-mid-fixed-25s.png —— 同一时刻面板
36/65 文件、3.4 MB/15.3 MB、进度条只填了约一半（旧图 36/36 + 满格）。

crates/app/src/dto/install.rs

@@ -31,7 +31,7 @@ impl InstallStage {
         match self {
             Self::Planning => "解析版本",
             Self::Downloading => "下载文件",
-            Self::Installing => "写入版本",
+            Self::Installing => "生成版本",
             Self::Registering => "登记实例",
             Self::Done => "已完成",
             Self::Failed => "失败",

crates/app/src/host/install.rs

@@ -1,12 +1,14 @@
-//! 安装：新建实例向导 / 下载页「安装」→ core 安装管线（原版 + Fabric/Quilt）→ 登记实例。
+//! 安装：新建实例向导 / 下载页「安装」→ core 安装管线 → 登记实例。
 //!
 //! 与 CLI `ull install` 同序：`RemoteSource::resolve → InstallPlan::build → execute → register`。
-//! 差异：进度经 [`super::job::HostTask::Install`] 回流（文件计数 + 字节 + 速度/ETA），
+//! Forge/NeoForge 多一段 installer processors（[`super::install_processors`]）：
+//! `ProcessorPlan::build → 依赖库下载 → 选 Java → 串行 java -cp`，**跑完才写版本 JSON**。
+//! 差异只在线程模型：进度经 [`super::job::HostTask::Install`] 回流（文件计数 + 字节 + 速度/ETA），
 //! 且整段跑在后台线程里（`block_on` 不占 UI 线程）。
 //!
-//! 加载器范围：原版 + Fabric/Quilt（纯库层）。Forge/NeoForge 要外调 java 跑 installer
+//! 加载器范围：原版 + Fabric/Quilt/Forge/NeoForge（四家，与 CLI 对齐）。OptiFine/LiteLoader
-//! processors（M35 的执行器在 CLI 侧），GUI 这一轮**显式拒装并说清去哪装**，
+//! 两家 core 侧都还没有安装管线，仍在 GUI 里显式拒装并说清去哪装。
-//! 而不是装出一个启动必崩的骨架。
+//! 失败一律落 `.ULL/logs/install.log`（[`super::install_journal`]），文案里带日志路径。
 
 use std::path::PathBuf;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -27,6 +29,8 @@ use crate::dto::{CreateRequest, InstallStage, LoaderKind};
 use crate::toast::{Toast, ToastKind};
 
 use super::env::HostEnv;
+use super::install_journal::Journal;
+use super::install_processors::{self, StageInput};
 use super::job::{spawn, HostTask, JobSender};
 use super::meter::{sink_for, Meter};
 
@@ -36,6 +40,26 @@ pub const CONCURRENCY: usize = 16;
 /// 用户取消的稳定文案（阶段边界生效）。
 pub const CANCELLED: &str = "已取消（阶段边界停下；已下载的文件保留，重装会续用）";
 
+/// 一次安装任务的运行上下文（后台线程内一路传下去，免得每个函数排七八个参数）。
+struct Job<'a> {
+    env: &'a HostEnv,
+    tx: &'a JobSender,
+    meter: &'a Arc<std::sync::Mutex<Meter>>,
+    cancel: &'a Arc<AtomicBool>,
+    journal: &'a Journal,
+}
+
+impl Job<'_> {
+    /// processor 段的进度出口（同一套 channel/meter/journal）。
+    fn reporter(&self) -> install_processors::Reporter<'_> {
+        install_processors::Reporter {
+            tx: self.tx,
+            meter: self.meter,
+            journal: self.journal,
+        }
+    }
+}
+
 /// 加载器徽标（`原版` / `Fabric 0.16.5`）。
 pub fn loader_label(kind: LoaderKind, version: &str) -> String {
     if kind == LoaderKind::Vanilla || version.trim().is_empty() {
@@ -45,20 +69,26 @@ pub fn loader_label(kind: LoaderKind, version: &str) -> String {
     }
 }
 
-/// GUI 侧支持的加载器（Forge/NeoForge 需要 installer processors）。
+/// GUI 侧支持的加载器（五选：原版 + 四家加载器，与 CLI 的 `--loader` 词表一致）。
+///
+/// 写成穷举 `matches!` 而不是 `true`：将来 core 加了第六种加载器，这里默认拒绝，
+/// 由 [`unsupported_reason`] 给出明确说法，而不是让它走进不属于它的安装分支。
 pub fn supported(kind: LoaderKind) -> bool {
     matches!(
         kind,
-        LoaderKind::Vanilla | LoaderKind::Fabric | LoaderKind::Quilt
+        LoaderKind::Vanilla
+            | LoaderKind::Fabric
+            | LoaderKind::Quilt
+            | LoaderKind::Forge
+            | LoaderKind::NeoForge
     )
 }
 
 /// 不支持的加载器 → 给用户的可执行建议。
 pub fn unsupported_reason(kind: LoaderKind) -> String {
     format!(
-        "{} 需要 installer processors（外调 java 改 jar），GUI 这一轮还没接入；请先在终端跑 `ull install <版本> --loader {}`，装完回实例页刷新即可启动。",
+        "{} 还没有接入安装管线（目前支持原版 + Fabric/Quilt/Forge/NeoForge）；请先在实例页导入已有版本，或换成受支持的加载器。",
-        kind.label(),
+        kind.label()
-        kind.as_str()
     )
 }
 
@@ -66,13 +96,28 @@ pub fn unsupported_reason(kind: LoaderKind) -> String {
 pub fn spawn_install(env: HostEnv, tx: JobSender, request: CreateRequest, cancel: Arc<AtomicBool>) {
     spawn("install", move || {
         let meter = Arc::new(std::sync::Mutex::new(Meter::new(&request)));
-        let result = run(&env, &tx, &request, &meter, &cancel);
+        let journal = Journal::open(&env);
+        journal.line(&format!(
+            "—— 开始安装 {}（{} {}）——",
+            request.instance_name(),
+            loader_label(request.loader, ""),
+            request.version
+        ));
+        let job = Job {
+            env: &env,
+            tx: &tx,
+            meter: &meter,
+            cancel: &cancel,
+            journal: &journal,
+        };
+        let result = run(&job, &request);
         let mut progress = meter
             .lock()
             .map(|guard| guard.progress.clone())
             .unwrap_or_else(|_| Meter::new(&request).progress);
         match result {
             Ok(name) => {
+                journal.line(&format!("完成：实例 {name} 已登记"));
                 progress.stage = InstallStage::Done;
                 progress.files_done = progress.files_total;
                 progress.message = format!("已安装 {name}（{}）", progress.loader);
@@ -88,15 +133,24 @@ pub fn spawn_install(env: HostEnv, tx: JobSender, request: CreateRequest, cancel
                 })));
             }
             Err(reason) => {
-                progress.stage = if reason == CANCELLED {
+                let cancelled = reason == CANCELLED;
+                progress.stage = if cancelled {
                     InstallStage::Cancelled
                 } else {
                     InstallStage::Failed
                 };
-                progress.message.clone_from(&reason);
+                // 失败文案带上日志路径：面板只有一行、Toast 4 秒就消失，
+                // 装日志是用户事后能自己回看的唯一渠道（进度板之外）。
+                let text = if cancelled {
+                    reason
+                } else {
+                    journal.line(&format!("安装未完成：{reason}"));
+                    format!("{reason}（日志：{}）", journal.path().display())
+                };
+                progress.message.clone_from(&text);
                 let _ = tx.send(HostTask::InstallDone {
                     progress: Box::new(progress),
-                    result: Err(reason),
+                    result: Err(text),
                 });
             }
         }
@@ -104,13 +158,7 @@ pub fn spawn_install(env: HostEnv, tx: JobSender, request: CreateRequest, cancel
 }
 
 /// 真安装（同步跑完，调用方在后台线程里）。
-fn run(
+fn run(job: &Job<'_>, request: &CreateRequest) -> Result<String, String> {
-    env: &HostEnv,
-    tx: &JobSender,
-    request: &CreateRequest,
-    meter: &Arc<std::sync::Mutex<Meter>>,
-    cancel: &Arc<AtomicBool>,
-) -> Result<String, String> {
     if request.version.trim().is_empty() {
         return Err("没有选择版本".to_string());
     }
@@ -118,26 +166,31 @@ fn run(
         return Err(unsupported_reason(request.loader));
     }
     let name = request.instance_name();
+    let env = job.env;
     let engine = super::engine::engine(env);
     {
-        let mut guard = meter.lock().map_err(|_| "进度锁失效".to_string())?;
+        let mut guard = job.meter.lock().map_err(|_| "进度锁失效".to_string())?;
         guard.stage(InstallStage::Planning, "正在解析版本清单…");
-        let _ = tx.send(HostTask::Install(Box::new(guard.progress.clone())));
+        let _ = job
+            .tx
+            .send(HostTask::Install(Box::new(guard.progress.clone())));
     }
 
-    if cancel.load(Ordering::SeqCst) {
+    if job.cancel.load(Ordering::SeqCst) {
         return Err(CANCELLED.to_string());
     }
     let version_id = if request.loader == LoaderKind::Vanilla {
-        install_vanilla(env, &engine, request, tx, meter, cancel)?
+        install_vanilla(job, &engine, request)?
     } else {
-        install_loader(env, &engine, request, tx, meter, cancel)?
+        install_loader(job, &engine, request)?
     };
 
     {
-        let mut guard = meter.lock().map_err(|_| "进度锁失效".to_string())?;
+        let mut guard = job.meter.lock().map_err(|_| "进度锁失效".to_string())?;
         guard.stage(InstallStage::Registering, "正在登记实例…");
-        let _ = tx.send(HostTask::Install(Box::new(guard.progress.clone())));
+        let _ = job
+            .tx
+            .send(HostTask::Install(Box::new(guard.progress.clone())));
     }
     let created_at =
         unlucky_core::launch::time::format_rfc3339_millis(unlucky_core::launch::time::now());
@@ -153,17 +206,15 @@ fn run(
 
 /// 原版安装（`resolve → plan → [prefetch 资源索引] → execute`）。
 fn install_vanilla(
-    env: &HostEnv,
+    job: &Job<'_>,
     engine: &DownloadEngine,
     request: &CreateRequest,
-    tx: &JobSender,
-    meter: &Arc<std::sync::Mutex<Meter>>,
-    cancel: &Arc<AtomicBool>,
 ) -> Result<String, String> {
+    let env = job.env;
     let version = request.version.trim();
     let meta_cache = env.layout.meta_cache();
     let now = now_ms();
-    let sink = sink_for(tx.clone(), Arc::clone(meter));
+    let sink = sink_for(job.tx.clone(), Arc::clone(job.meter));
     block_on(async {
         let source = RemoteSource::new(engine, &env.game, &meta_cache, now);
         let resolved = source.resolve(version).await.map_err(install_error)?;
@@ -197,7 +248,7 @@ fn install_vanilla(
         }
         let (bytes_total, _) = plan.total_bytes();
         {
-            let mut guard = meter.lock().map_err(|_| "进度锁失效".to_string())?;
+            let mut guard = job.meter.lock().map_err(|_| "进度锁失效".to_string())?;
             guard.progress.files_total = u64::try_from(plan.file_count()).unwrap_or(u64::MAX);
             guard.progress.bytes_total = bytes_total;
             guard.stage(
@@ -205,7 +256,7 @@ fn install_vanilla(
                 &format!("开始下载 {} 个文件…", plan.file_count()),
             );
         }
-        if cancel.load(Ordering::SeqCst) {
+        if job.cancel.load(Ordering::SeqCst) {
             return Err(CANCELLED.to_string());
         }
         let report = execute(engine, &plan, CONCURRENCY, Some(sink))
@@ -216,15 +267,13 @@ fn install_vanilla(
     })
 }
 
-/// 加载器安装（原版前置 → 加载器库 → 版本 JSON 落盘）。
+/// 加载器安装（原版前置 → installer processors → 加载器库 → 版本 JSON 落盘）。
 fn install_loader(
-    env: &HostEnv,
+    job: &Job<'_>,
     engine: &DownloadEngine,
     request: &CreateRequest,
-    tx: &JobSender,
-    meter: &Arc<std::sync::Mutex<Meter>>,
-    cancel: &Arc<AtomicBool>,
 ) -> Result<String, String> {
+    let env = job.env;
     let version = request.version.trim();
     let kind = CoreLoaderKind::parse(request.loader.as_str())
         .ok_or_else(|| format!("未知加载器 `{}`", request.loader.as_str()))?;
@@ -237,6 +286,12 @@ fn install_loader(
             .await
     })
     .map_err(|error| error.to_string())?;
+    job.journal.line(&format!(
+        "加载器解析：{} {} → {}",
+        release.kind.label(),
+        release.loader_version,
+        release.version_id
+    ));
 
     let plan = LoaderInstallPlan::build(LoaderPlanInput {
         layout: &env.game,
@@ -247,22 +302,47 @@ fn install_loader(
     if plan.vanilla_install_needed {
         let mut vanilla = request.clone();
         vanilla.loader = LoaderKind::Vanilla;
-        install_vanilla(env, engine, &vanilla, tx, meter, cancel)?;
+        install_vanilla(job, engine, &vanilla)?;
+    }
+    // 两段（加载器库 + 处理器依赖库）在动手前一次预记账：进度条只走一条单调曲线，
+    // 处理器依赖库下完不会先满格、再在加载器库开始时回落到一半。
+    {
+        let mut guard = job.meter.lock().map_err(|_| "进度锁失效".to_string())?;
+        let (bytes, _) = plan.install.total_bytes();
+        guard.expect(plan.files().len(), bytes);
+    }
+    // Forge/NeoForge：installer processors 必须先跑完，`execute` 才允许写版本 JSON。
+    if release.requires_installer() {
+        let input = StageInput {
+            kind: release.kind,
+            mc_version: &release.mc_version,
+            version_id: &release.version_id,
+            profile: release.install_profile.as_ref(),
+            installer: release.installer.as_deref(),
+            installed: env.game.is_version_installed(&release.version_id),
+        };
+        // `None` = 这一版不需要跑处理器（版本 JSON 已在盘上 / profile 没有 client 侧步骤），
+        // 进度与日志都由处理器段自己写全，这里只消费返回值。
+        let _ = install_processors::stage(
+            env,
+            engine,
+            &input,
+            &install_processors::CORE,
+            &job.reporter(),
+            job.cancel,
+        )?;
     }
     {
-        let mut guard = meter.lock().map_err(|_| "进度锁失效".to_string())?;
+        let mut guard = job.meter.lock().map_err(|_| "进度锁失效".to_string())?;
-        guard.progress.files_total += u64::try_from(plan.files().len()).unwrap_or(u64::MAX);
-        let (bytes, _) = plan.install.total_bytes();
-        guard.progress.bytes_total = guard.progress.bytes_total.max(bytes);
         guard.stage(
             InstallStage::Downloading,
             &format!("开始下载加载器库（{} 个文件）…", plan.files().len()),
         );
     }
-    if cancel.load(Ordering::SeqCst) {
+    if job.cancel.load(Ordering::SeqCst) {
         return Err(CANCELLED.to_string());
     }
-    let sink = sink_for(tx.clone(), Arc::clone(meter));
+    let sink = sink_for(job.tx.clone(), Arc::clone(job.meter));
     let report = block_on(async {
         execute(engine, &plan.install, CONCURRENCY, Some(sink))
             .await

crates/app/src/host/install_journal.rs

@@ -0,0 +1,79 @@
+//! 安装过程的可回溯日志（`.ULL/logs/install.log`，一轮一行）。
+//!
+//! 起因（M45）：Forge/NeoForge 装失败时，GUI 只有一行 Toast，processor 的 stderr 尾部
+//! 与「哪一步挂了」在面板一关就没了。这里把安装过程按行追加到 `.ULL/logs/`
+//! （与 `auth.jsonl` 同一分区），失败文案里带上日志路径，用户能自己回看。
+//!
+//! 三条纪律（与 auth 日志同源）：
+//! 1. **只追加**，不轮转、不截断（体积由「一行一条、只记诊断字段」控制）；
+//! 2. **只记诊断字段**：阶段、processor 坐标、退出码、已脱敏的 stderr 尾部（core 侧脱敏）；
+//! 3. **写盘尽力而为**：开不了文件就静默跳过，绝不让日志失败连累安装。
+
+use std::io::Write;
+use std::path::{Path, PathBuf};
+
+use unlucky_core::launch::time;
+
+use super::env::HostEnv;
+
+/// 日志文件名（在 `.ULL/logs/` 下）。
+pub const INSTALL_LOG_FILE: &str = "install.log";
+
+/// 一轮安装的日志句柄（`Clone` 很便宜：只有一个路径）。
+#[derive(Debug, Clone)]
+pub struct Journal {
+    path: PathBuf,
+}
+
+impl Journal {
+    /// 按数据根打开（`logs/` 不存在就补建；建不出来只是没有日志）。
+    pub fn open(env: &HostEnv) -> Self {
+        let dir = env.layout.logs();
+        let _ = std::fs::create_dir_all(&dir);
+        Self {
+            path: dir.join(INSTALL_LOG_FILE),
+        }
+    }
+
+    /// 日志路径（失败文案里给用户看）。
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
+    /// 追加一行（自动补 RFC3339 时间戳；写失败静默）。
+    pub fn line(&self, text: &str) {
+        let Ok(mut file) = std::fs::OpenOptions::new()
+            .create(true)
+            .append(true)
+            .open(&self.path)
+        else {
+            return;
+        };
+        let _ = writeln!(
+            file,
+            "[{}] {text}",
+            time::format_rfc3339_millis(time::now())
+        );
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn lines_are_appended_with_a_timestamp() {
+        let root = std::env::temp_dir().join(format!("ull-install-journal-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&root);
+        let env = HostEnv::at_root(&root);
+        let journal = Journal::open(&env);
+        journal.line("第一行");
+        journal.line("第二行");
+        let text = std::fs::read_to_string(journal.path()).expect("日志存在");
+        assert!(text.contains("第一行") && text.contains("第二行"), "{text}");
+        assert_eq!(text.lines().count(), 2);
+        assert!(text.starts_with("[2"), "带时间戳：{text}");
+        assert_eq!(journal.path(), env.layout.logs().join(INSTALL_LOG_FILE));
+        std::fs::remove_dir_all(&root).ok();
+    }
+}

crates/app/src/host/install_processors.rs

@@ -0,0 +1,378 @@
+//! Forge / NeoForge 的 installer processors 段（M45：GUI 与 CLI 行为对齐）。
+//!
+//! 顺序与 CLI `ull install --loader forge` 完全一致（`crates/cli/src/commands/install/
+//! loader_processors.rs`），只是把进度接到 GUI 的回流通道上：
+//!
+//! ```text
+//! ProcessorPlan::build（纯计算：变量表 + 每步 java -cp + 依赖库清单）
+//!   → download_libraries（M27 引擎；进度回流 HostTask::Install）
+//!   → select_java（M33 解析链：托管 > JAVA_HOME > PATH > 扫盘）
+//!   → run（串行 java -cp；每步一条面板文案 + 一行装日志）
+//! ```
+//!
+//! 四条硬约束（与 CLI 同源，GUI 侧一条都不放宽）：
+//!
+//! 1. **processors 跑完才允许写版本 JSON**：版本清单存在 = 这版装完了，抢在 processors
+//!    前写会留下启动必崩却被报成"已安装"的实例（顺序由 `install_loader` 保证）；
+//! 2. **幂等**：版本 JSON 已在盘上 = 上一轮跑完了，整段跳过；
+//! 3. **取消在阶段边界生效**：处理器阶段是原子段（串行外调 java，进程内没有取消钩子），
+//!    进入前与退出后各查一次 `cancel`；
+//! 4. **失败不静默**：结构化文案（带 `processor_*` 大类码）+ 装日志一行一条，由调用方
+//!    再补 Toast（`HostTask::InstallDone` 的既有通路）。
+//!
+//! 执行后端走 [`Backend`]：真实实现 [`CoreBackend`] 直接转调 core，单测注入 fake，
+//! 因此「计划怎么组、Java 找不到怎么说、依赖库下漏怎么报」都能在没有网络/没有 JDK
+//! 的机器上断言。
+
+use std::path::Path;
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::sync::{Arc, Mutex};
+
+use unlucky_core::addon::loader::forge::InstallProfile;
+use unlucky_core::addon::loader::processors::{
+    self, ProcessorError, ProcessorPlan, ProcessorPlanInput, ProcessorRun, StepOutcome, StepSink,
+    StepStatus,
+};
+use unlucky_core::addon::loader::LoaderKind as CoreLoaderKind;
+use unlucky_core::download::blocking::block_on;
+use unlucky_core::download::DownloadEngine;
+use unlucky_core::game::arguments::Environment;
+use unlucky_core::game::install::{InstallReport, PlanFile, ProgressSink};
+use unlucky_core::game::java::{JavaRequirement, JavaRuntime};
+
+use crate::dto::InstallStage;
+
+use super::env::HostEnv;
+use super::install::{CANCELLED, CONCURRENCY};
+use super::install_journal::Journal;
+use super::job::{HostTask, JobSender};
+use super::meter::{sink_for, Meter};
+
+/// 真实后端（无状态，可以放静态里复用）。
+pub(super) const CORE: CoreBackend = CoreBackend;
+
+/// processors 段需要的输入（从 `LoaderRelease` 摘出来，便于单测构造）。
+pub(super) struct StageInput<'a> {
+    /// 加载器种类（补库时 maven 基址的兜底来源）。
+    pub kind: CoreLoaderKind,
+    /// 目标原版版本。
+    pub mc_version: &'a str,
+    /// loader 版本 id（依赖库落点 + 临时目录名）。
+    pub version_id: &'a str,
+    /// installer 里读出来的 install profile（`requires_installer` 为真时必须有）。
+    pub profile: Option<&'a InstallProfile>,
+    /// installer jar 的磁盘路径。
+    pub installer: Option<&'a Path>,
+    /// 版本 JSON 已在盘上 = 上一轮跑完了，整段跳过（幂等）。
+    pub installed: bool,
+}
+
+/// processors 段的执行后端（真实实现转调 core；单测注入 fake）。
+pub(super) trait Backend {
+    /// 下载 processor 依赖库（M27 引擎：镜像/健康度/退避/校验）。
+    fn download_libraries(
+        &self,
+        engine: &DownloadEngine,
+        files: &[PlanFile],
+        sink: Option<ProgressSink>,
+    ) -> InstallReport;
+    /// 按 M33 的解析链挑一个能跑 installer 的 Java。
+    fn select_java(&self, managed: &Path, requirement: &JavaRequirement) -> Option<JavaRuntime>;
+    /// 串行跑 processors。
+    fn run(
+        &self,
+        plan: &ProcessorPlan,
+        java: &JavaRuntime,
+        sink: Option<StepSink>,
+    ) -> Result<ProcessorRun, ProcessorError>;
+}
+
+/// 真实后端：三件事全部转调 core 的同一个执行器（CLI 用的就是它）。
+pub(super) struct CoreBackend;
+
+impl Backend for CoreBackend {
+    fn download_libraries(
+        &self,
+        engine: &DownloadEngine,
+        files: &[PlanFile],
+        sink: Option<ProgressSink>,
+    ) -> InstallReport {
+        block_on(processors::download_libraries(
+            engine,
+            files,
+            CONCURRENCY,
+            sink,
+        ))
+    }
+
+    fn select_java(&self, managed: &Path, requirement: &JavaRequirement) -> Option<JavaRuntime> {
+        processors::select_java(managed, requirement)
+    }
+
+    fn run(
+        &self,
+        plan: &ProcessorPlan,
+        java: &JavaRuntime,
+        sink: Option<StepSink>,
+    ) -> Result<ProcessorRun, ProcessorError> {
+        processors::run(plan, java, sink)
+    }
+}
+
+/// 段内的进度出口：进度面板（`HostTask::Install`）+ 装日志。
+pub(super) struct Reporter<'a> {
+    /// 后台线程 → host 的通道。
+    pub tx: &'a JobSender,
+    /// 进度记账器。
+    pub meter: &'a Arc<Mutex<Meter>>,
+    /// 装日志。
+    pub journal: &'a Journal,
+}
+
+impl Reporter<'_> {
+    /// 换阶段并推一条进度。
+    fn stage(&self, stage: InstallStage, message: &str) {
+        let Ok(mut guard) = self.meter.lock() else {
+            return;
+        };
+        guard.stage(stage, message);
+        let _ = self
+            .tx
+            .send(HostTask::Install(Box::new(guard.progress.clone())));
+    }
+
+    /// 先把待下的库记账（文件数 + 已知字节），下载回调再逐个累加。
+    fn expect(&self, files: usize, bytes: u64) {
+        let Ok(mut guard) = self.meter.lock() else {
+            return;
+        };
+        guard.expect(files, bytes);
+    }
+
+    /// 失败留痕（文案由调用方决定怎么呈现；这里只保证日志里有一条）。
+    fn fail(&self, reason: String) -> String {
+        self.journal.line(&format!("失败：{reason}"));
+        reason
+    }
+}
+
+/// 跑 Forge / NeoForge 的 installer processors（`Ok(None)` = 这一轮不需要跑）。
+///
+/// # Errors
+///
+/// 元数据缺 profile/installer、依赖库没下全、找不到可用 Java、processor 非零退出、
+/// 产物没落盘、用户取消时返回给 UI 的文案（已写进装日志）。
+pub(super) fn stage(
+    env: &HostEnv,
+    engine: &DownloadEngine,
+    input: &StageInput<'_>,
+    backend: &dyn Backend,
+    reporter: &Reporter<'_>,
+    cancel: &Arc<AtomicBool>,
+) -> Result<Option<ProcessorRun>, String> {
+    if input.installed {
+        reporter.journal.line(&format!(
+            "{} 的版本 JSON 已在盘上，跳过 installer processors",
+            input.version_id
+        ));
+        return Ok(None);
+    }
+    let (Some(profile), Some(installer)) = (input.profile, input.installer) else {
+        return Err(reporter.fail(metadata_missing(input)));
+    };
+    reporter.stage(InstallStage::Installing, "正在组 installer 处理器计划…");
+    let scratch = env
+        .layout
+        .cache()
+        .join("processors")
+        .join(safe_name(input.version_id));
+    let plan = ProcessorPlan::build(ProcessorPlanInput {
+        kind: input.kind,
+        mc_version: input.mc_version,
+        version_id: input.version_id,
+        profile,
+        layout: &env.game,
+        installer,
+        scratch: &scratch,
+        environment: &Environment::host(),
+    })
+    .map_err(|error| reporter.fail(diagnostic(&error)))?;
+    for warning in &plan.warnings {
+        reporter.journal.line(&format!("规划告警：{warning}"));
+    }
+    if plan.is_empty() {
+        reporter
+            .journal
+            .line("install profile 没有 client 侧 processor，跳过这一段");
+        return Ok(None);
+    }
+
+    let total = plan.step_count();
+    let bytes = plan.libraries.iter().filter_map(|file| file.size).sum();
+    reporter.expect(plan.libraries.len(), bytes);
+    reporter.stage(
+        InstallStage::Downloading,
+        &format!("下载 installer 依赖库（{} 个文件）…", plan.libraries.len()),
+    );
+    if cancel.load(Ordering::SeqCst) {
+        return Err(CANCELLED.to_string());
+    }
+    let sink = sink_for(reporter.tx.clone(), Arc::clone(reporter.meter));
+    let libraries = backend.download_libraries(engine, &plan.libraries, Some(sink));
+    if !libraries.is_complete() {
+        return Err(reporter.fail(libraries_failed(&libraries)));
+    }
+
+    let managed = env.layout.java_managed();
+    let Some(java) = backend.select_java(&managed, &plan.java_requirement) else {
+        return Err(reporter.fail(java_missing(&plan.java_requirement, &managed)));
+    };
+    reporter.journal.line(&format!(
+        "用 {}（{}）跑 {total} 步 processor",
+        java.binary.display(),
+        java_label(&java)
+    ));
+    reporter.stage(
+        InstallStage::Installing,
+        &format!("运行 installer 处理器 0/{total}（{}）…", java_label(&java)),
+    );
+    if cancel.load(Ordering::SeqCst) {
+        return Err(CANCELLED.to_string());
+    }
+
+    let steps = step_sink(
+        reporter.tx.clone(),
+        Arc::clone(reporter.meter),
+        reporter.journal.clone(),
+        total,
+    );
+    let run = backend
+        .run(&plan, &java, Some(steps))
+        .map_err(|error| reporter.fail(diagnostic(&error)))?;
+    for warning in &run.warnings {
+        reporter.journal.line(&format!("执行告警：{warning}"));
+    }
+    reporter.journal.line(&format!(
+        "processors 完成：执行 {} 步、跳过 {} 步",
+        run.executed(),
+        run.skipped()
+    ));
+    reporter.stage(
+        InstallStage::Installing,
+        &format!(
+            "installer 处理器完成（执行 {} 步、跳过 {} 步），正在写入版本清单…",
+            run.executed(),
+            run.skipped()
+        ),
+    );
+    if cancel.load(Ordering::SeqCst) {
+        return Err(CANCELLED.to_string());
+    }
+    Ok(Some(run))
+}
+
+/// 每步完成的回调：面板一行 + 装日志一行。
+///
+/// `StepSink` 要求 `'static`，所以这里全持所有权（通道/记账器/日志都是克隆）。
+fn step_sink(tx: JobSender, meter: Arc<Mutex<Meter>>, journal: Journal, total: usize) -> StepSink {
+    Arc::new(move |outcome: &StepOutcome| {
+        let line = step_line(outcome, total);
+        journal.line(&line);
+        let Ok(mut guard) = meter.lock() else {
+            return;
+        };
+        guard.stage(InstallStage::Installing, &line);
+        let _ = tx.send(HostTask::Install(Box::new(guard.progress.clone())));
+    })
+}
+
+/// 一步的进度/日志文案（纯函数，单测直接断言）。
+pub(super) fn step_line(outcome: &StepOutcome, total: usize) -> String {
+    let suffix = match outcome.status {
+        StepStatus::Skipped => "（产物已就绪，跳过）".to_string(),
+        StepStatus::Executed => format!("（{} ms）", outcome.elapsed_ms),
+    };
+    format!(
+        "installer 处理器 {}/{}：{}{suffix}",
+        outcome.index, total, outcome.label
+    )
+}
+
+/// processor 错误 → 用户可读文案（保留 `processor_*` 大类码，便于按码搜日志）。
+pub(super) fn diagnostic(error: &ProcessorError) -> String {
+    let mut text = format!("{}（{}）", error.message(), error.kind().as_str());
+    if let Some(hint) = error.hint() {
+        text.push_str("；建议：");
+        text.push_str(hint);
+    }
+    text
+}
+
+/// 缺 Java 运行时的专用文案（比通用错误多给一条「去哪装」）。
+pub(super) fn java_missing(requirement: &JavaRequirement, managed: &Path) -> String {
+    format!(
+        "跑 installer 需要 {}，但一个可用的 Java 运行时都没找到；请到「Java」页安装托管 JDK，或把 JAVA_HOME 指向可用的 JDK（托管目录 {}）",
+        requirement.describe(),
+        managed.display()
+    )
+}
+
+/// 依赖库没下全 → 列前三条失败明细。
+pub(super) fn libraries_failed(report: &InstallReport) -> String {
+    let details: Vec<String> = report
+        .failures(3)
+        .iter()
+        .filter_map(|outcome| {
+            outcome
+                .failure
+                .as_ref()
+                .map(|failure| format!("{}：{}", outcome.name, failure.message))
+        })
+        .collect();
+    format!(
+        "installer 依赖库没下全（{} 个失败，共 {} 个）：{}",
+        report.failed(),
+        report.files.len(),
+        details.join("；")
+    )
+}
+
+/// 需要 installer 但元数据不全（缓存半截 / 换线路重解析过）。
+fn metadata_missing(input: &StageInput<'_>) -> String {
+    format!(
+        "{} {} 需要跑 installer processors，但没拿到 install profile / installer 路径；重跑一次即可（元数据缓存可能不完整）",
+        input.kind.label(),
+        input.version_id
+    )
+}
+
+/// Java 的一行短标识（`Java 21 · managed`）。
+fn java_label(java: &JavaRuntime) -> String {
+    match java.major {
+        Some(major) => format!("Java {major} · {}", java.origin.as_str()),
+        None => format!("Java 主版本未知 · {}", java.origin.as_str()),
+    }
+}
+
+/// 版本 id → 可做目录名的片段（`+` 与路径分隔符都换掉，与 CLI 同规则）。
+fn safe_name(raw: &str) -> String {
+    raw.chars()
+        .map(|ch| {
+            if ch.is_ascii_alphanumeric() || matches!(ch, '.' | '-' | '_') {
+                ch
+            } else {
+                '_'
+            }
+        })
+        .collect::<String>()
+        .trim_end_matches('.')
+        .to_string()
+}
+
+#[cfg(test)]
+#[path = "install_processors_fixture.rs"]
+mod fixture;
+
+#[cfg(test)]
+#[path = "install_processors_tests.rs"]
+mod tests;

crates/app/src/host/install_processors_fixture.rs

@@ -0,0 +1,272 @@
+//! installer processors 段的单测夹具（拆文件守 400 行上限）。
+//!
+//! 不需要网络、不需要 JDK、不真的起 java：`Harness` 给一个临时数据根 + 进度通道，
+//! `Fake` 回放预置的下载/Java/执行结果并记录被调顺序与组出来的命令行。
+
+use std::cell::RefCell;
+use std::path::{Path, PathBuf};
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
+use std::sync::mpsc::Receiver;
+use std::sync::{Arc, Mutex};
+
+use unlucky_core::addon::loader::forge::{InstallProfile, Processor};
+use unlucky_core::addon::loader::processors::{
+    ProcessorError, ProcessorPlan, ProcessorRun, StepOutcome, StepSink, StepStatus,
+};
+use unlucky_core::addon::loader::LoaderKind as CoreLoaderKind;
+use unlucky_core::download::{DownloadEngine, DownloadErrorKind};
+use unlucky_core::game::install::{
+    FileFailure, FileOutcome, FileStatus, InstallReport, PlanFile, ProgressSink,
+};
+use unlucky_core::game::java::{JavaOrigin, JavaRequirement, JavaRuntime};
+
+use super::{Backend, Reporter, StageInput};
+use crate::dto::{CreateRequest, LoaderKind};
+use crate::host::env::HostEnv;
+use crate::host::install_journal::Journal;
+use crate::host::job::{channel, HostTask, JobSender};
+use crate::host::meter::Meter;
+
+static SEQ: AtomicUsize = AtomicUsize::new(0);
+
+/// 一步的计划视图（序号 / 坐标 / 参数 / classpath 条数）。
+pub(super) type StepView = (usize, String, Vec<String>, usize);
+
+/// 一段 cases 的公共环境：临时数据根 + 引擎 + 进度通道。
+pub(super) struct Harness {
+    dir: PathBuf,
+    pub(super) env: HostEnv,
+    pub(super) engine: DownloadEngine,
+    tx: JobSender,
+    rx: Receiver<HostTask>,
+    pub(super) meter: Arc<Mutex<Meter>>,
+    pub(super) journal: Journal,
+    pub(super) cancel: Arc<AtomicBool>,
+}
+
+impl Harness {
+    pub(super) fn new() -> Self {
+        let seq = SEQ.fetch_add(1, Ordering::SeqCst);
+        let dir = std::env::temp_dir().join(format!("ull-proc-{}-{seq}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&dir);
+        let env = HostEnv::at_root(&dir);
+        let engine = crate::host::engine::engine(&env);
+        let request = CreateRequest {
+            version: "1.20.1".to_string(),
+            loader: LoaderKind::Forge,
+            loader_version: "47.2.0".to_string(),
+            name: "proc".to_string(),
+        };
+        let (tx, rx) = channel();
+        Self {
+            journal: Journal::open(&env),
+            meter: Arc::new(Mutex::new(Meter::new(&request))),
+            cancel: Arc::new(AtomicBool::new(false)),
+            dir,
+            env,
+            engine,
+            tx,
+            rx,
+        }
+    }
+
+    pub(super) fn reporter(&self) -> Reporter<'_> {
+        Reporter {
+            tx: &self.tx,
+            meter: &self.meter,
+            journal: &self.journal,
+        }
+    }
+
+    /// 进度面板收到的所有文案。
+    pub(super) fn messages(&self) -> Vec<String> {
+        self.rx
+            .try_iter()
+            .filter_map(|task| match task {
+                HostTask::Install(progress) => Some(progress.message.clone()),
+                _ => None,
+            })
+            .collect()
+    }
+
+    /// 装日志全文。
+    pub(super) fn log(&self) -> String {
+        std::fs::read_to_string(self.journal.path()).unwrap_or_default()
+    }
+}
+
+impl Drop for Harness {
+    fn drop(&mut self) {
+        std::fs::remove_dir_all(&self.dir).ok();
+    }
+}
+
+/// 注入用的假后端：回放预置结果 + 记录调用顺序与被组出来的命令行。
+pub(super) struct Fake {
+    pub(super) libraries_ok: bool,
+    pub(super) java: Option<JavaRuntime>,
+    pub(super) run_error: Option<ProcessorError>,
+    calls: RefCell<Vec<&'static str>>,
+    steps: RefCell<Vec<StepView>>,
+}
+
+impl Fake {
+    pub(super) fn new() -> Self {
+        Self {
+            libraries_ok: true,
+            java: Some(java()),
+            run_error: None,
+            calls: RefCell::new(Vec::new()),
+            steps: RefCell::new(Vec::new()),
+        }
+    }
+
+    pub(super) fn calls(&self) -> Vec<&'static str> {
+        self.calls.borrow().clone()
+    }
+
+    /// 被组出来的每步（序号 / 坐标 / 参数 / classpath 条数）。
+    pub(super) fn steps(&self) -> Vec<StepView> {
+        self.steps.borrow().clone()
+    }
+}
+
+impl Backend for Fake {
+    fn download_libraries(
+        &self,
+        _engine: &DownloadEngine,
+        files: &[PlanFile],
+        _sink: Option<ProgressSink>,
+    ) -> InstallReport {
+        self.calls.borrow_mut().push("libraries");
+        let ok = self.libraries_ok;
+        let outcomes = files
+            .iter()
+            .map(|file| FileOutcome {
+                role: file.role,
+                name: file.name.clone(),
+                dest: file.dest.clone(),
+                status: if ok {
+                    FileStatus::Skipped
+                } else {
+                    FileStatus::Failed
+                },
+                bytes: 0,
+                source: None,
+                failure: (!ok).then(|| FileFailure {
+                    kind: DownloadErrorKind::Network,
+                    message: "连接超时".to_string(),
+                }),
+            })
+            .collect();
+        InstallReport {
+            files: outcomes,
+            version_json: None,
+            warnings: Vec::new(),
+        }
+    }
+
+    fn select_java(&self, _managed: &Path, _requirement: &JavaRequirement) -> Option<JavaRuntime> {
+        self.calls.borrow_mut().push("java");
+        self.java.clone()
+    }
+
+    fn run(
+        &self,
+        plan: &ProcessorPlan,
+        java: &JavaRuntime,
+        sink: Option<StepSink>,
+    ) -> Result<ProcessorRun, ProcessorError> {
+        self.calls.borrow_mut().push("run");
+        *self.steps.borrow_mut() = plan
+            .steps
+            .iter()
+            .map(|step| {
+                (
+                    step.index,
+                    step.label.clone(),
+                    step.args.clone(),
+                    step.classpath.len(),
+                )
+            })
+            .collect();
+        if let Some(error) = &self.run_error {
+            return Err(error.clone());
+        }
+        let outcomes: Vec<StepOutcome> = plan
+            .steps
+            .iter()
+            .map(|step| StepOutcome {
+                index: step.index,
+                label: step.label.clone(),
+                status: StepStatus::Executed,
+                outputs: step.outputs.len(),
+                elapsed_ms: 12,
+                stdout_tail: None,
+                stderr_tail: None,
+            })
+            .collect();
+        if let Some(sink) = &sink {
+            for outcome in &outcomes {
+                sink(outcome);
+            }
+        }
+        Ok(ProcessorRun {
+            java: java.clone(),
+            steps: outcomes,
+            warnings: Vec::new(),
+        })
+    }
+}
+
+/// 一个主版本已知的假 Java。
+pub(super) fn java() -> JavaRuntime {
+    JavaRuntime {
+        binary: PathBuf::from("java"),
+        origin: JavaOrigin::Managed,
+        version: Some("21.0.4".to_string()),
+        major: Some(21),
+        bits: 64,
+        vendor: Some("temurin".to_string()),
+    }
+}
+
+/// 一个最小可用的 install profile：一个 client 侧 processor、两个字面量参数。
+pub(super) fn profile() -> InstallProfile {
+    let mut profile = InstallProfile::default();
+    profile.processors.push(Processor {
+        sides: vec!["client".to_string()],
+        jar: Some("net.minecraftforge:installertools:1.3.0".to_string()),
+        classpath: vec!["net.minecraftforge:jarsplitter:1.1.4".to_string()],
+        args: vec!["--task".to_string(), "'MCP_DATA'".to_string()],
+        ..Processor::default()
+    });
+    profile
+}
+
+pub(super) fn input<'a>(profile: &'a InstallProfile, installer: &'a Path) -> StageInput<'a> {
+    StageInput {
+        kind: CoreLoaderKind::Forge,
+        mc_version: "1.20.1",
+        version_id: "1.20.1-forge-47.2.0",
+        profile: Some(profile),
+        installer: Some(installer),
+        installed: false,
+    }
+}
+
+pub(super) fn installer() -> PathBuf {
+    PathBuf::from("cache/meta/forge-installer.jar")
+}
+
+pub(super) fn outcome(status: StepStatus) -> StepOutcome {
+    StepOutcome {
+        index: 3,
+        label: "net.minecraftforge:installertools:1.3.0".to_string(),
+        status,
+        outputs: 2,
+        elapsed_ms: 1234,
+        stdout_tail: None,
+        stderr_tail: None,
+    }
+}

crates/app/src/host/install_processors_tests.rs

@@ -0,0 +1,213 @@
+//! host/install_processors.rs 的单测（拆文件守 400 行上限）。
+//!
+//! 夹具在 [`super::fixture`]：这里只断言「计划怎么组」「找不到 Java 怎么说」
+//! 「哪一步挂了怎么报」「进度文案长什么样」。
+
+use std::path::PathBuf;
+
+use unlucky_core::addon::loader::forge::InstallProfile;
+use unlucky_core::addon::loader::processors::{ProcessorError, StepStatus};
+use unlucky_core::addon::loader::LoaderKind as CoreLoaderKind;
+use unlucky_core::download::DownloadErrorKind;
+use unlucky_core::game::install::{FileFailure, FileOutcome, FileRole, FileStatus, InstallReport};
+use unlucky_core::game::java::JavaRequirement;
+
+use super::fixture::{input, installer, outcome, profile, Fake, Harness};
+use super::{diagnostic, java_missing, libraries_failed, stage, step_line, StageInput};
+
+#[test]
+fn step_line_names_the_step_and_marks_the_outcome() {
+    let executed = step_line(&outcome(StepStatus::Executed), 9);
+    assert_eq!(
+        executed,
+        "installer 处理器 3/9：net.minecraftforge:installertools:1.3.0（1234 ms）"
+    );
+    let skipped = step_line(&outcome(StepStatus::Skipped), 9);
+    assert!(skipped.contains("产物已就绪"), "{skipped}");
+}
+
+#[test]
+fn diagnostic_keeps_the_stable_code_and_the_hint() {
+    let failed = ProcessorError::failed("net.minecraftforge:installertools:1.3.0", "1", "boom")
+        .with_hint("确认 Java 版本与磁盘权限");
+    let text = diagnostic(&failed);
+    assert!(text.contains("processor_failed"), "{text}");
+    assert!(text.contains("退出码 1"), "{text}");
+    assert!(text.contains("boom"), "stderr 尾部要留：{text}");
+    assert!(text.contains("建议：确认 Java 版本"), "{text}");
+
+    let plan = diagnostic(&ProcessorError::plan("install profile 缺 `jar`"));
+    assert!(plan.contains("processor_plan"), "{plan}");
+}
+
+#[test]
+fn java_missing_points_at_the_java_page() {
+    let managed = PathBuf::from("/tmp/.ULL/java");
+    let text = java_missing(&JavaRequirement::table(21, None), &managed);
+    assert!(text.contains("Java 21+"), "{text}");
+    assert!(text.contains("Java」页"), "{text}");
+    assert!(text.contains("JAVA_HOME"), "{text}");
+    assert!(text.contains(&managed.display().to_string()), "{text}");
+}
+
+#[test]
+fn libraries_failed_lists_at_most_three() {
+    let files: Vec<FileOutcome> = (0..4)
+        .map(|index| FileOutcome {
+            role: FileRole::Library,
+            name: format!("lib{index}.jar"),
+            dest: PathBuf::from(format!("lib{index}.jar")),
+            status: FileStatus::Failed,
+            bytes: 0,
+            source: None,
+            failure: Some(FileFailure {
+                kind: DownloadErrorKind::Network,
+                message: "连接超时".to_string(),
+            }),
+        })
+        .collect();
+    let report = InstallReport {
+        files,
+        version_json: None,
+        warnings: Vec::new(),
+    };
+    let text = libraries_failed(&report);
+    assert!(text.contains("4 个失败，共 4 个"), "{text}");
+    assert!(text.contains("lib0.jar"), "{text}");
+    assert!(!text.contains("lib3.jar"), "最多列三条：{text}");
+}
+
+#[test]
+fn stage_skips_when_the_version_json_is_already_there() {
+    let h = Harness::new();
+    let installer = installer();
+    let profile = profile();
+    let mut input = input(&profile, &installer);
+    input.installed = true;
+    let fake = Fake::new();
+    let result = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel);
+    assert!(matches!(result, Ok(None)));
+    assert!(fake.calls().is_empty(), "已装完就不该再动网络/Java");
+    assert!(h.log().contains("跳过 installer processors"), "{}", h.log());
+}
+
+#[test]
+fn stage_skips_an_empty_processor_list() {
+    let h = Harness::new();
+    let installer = installer();
+    let profile = InstallProfile::default();
+    let input = input(&profile, &installer);
+    let fake = Fake::new();
+    let result = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel);
+    assert!(matches!(result, Ok(None)), "没有 processor 就没这段");
+    assert!(fake.calls().is_empty());
+}
+
+#[test]
+fn stage_reports_missing_installer_metadata() {
+    let h = Harness::new();
+    let input = StageInput {
+        kind: CoreLoaderKind::Forge,
+        mc_version: "1.20.1",
+        version_id: "1.20.1-forge-47.2.0",
+        profile: None,
+        installer: None,
+        installed: false,
+    };
+    let fake = Fake::new();
+    let err = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel).unwrap_err();
+    assert!(err.contains("install profile"), "{err}");
+    assert!(h.log().contains("失败："), "{}", h.log());
+}
+
+#[test]
+fn stage_builds_the_command_line_from_the_install_profile() {
+    let h = Harness::new();
+    let installer = installer();
+    let profile = profile();
+    let input = input(&profile, &installer);
+    let fake = Fake::new();
+    let run = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel)
+        .expect("stage 成功")
+        .expect("应当真的跑了 processors");
+    assert_eq!(run.executed(), 1);
+    let steps = fake.steps();
+    assert_eq!(steps.len(), 1);
+    let (index, label, args, classpath) = &steps[0];
+    assert_eq!(*index, 1);
+    assert_eq!(label, "net.minecraftforge:installertools:1.3.0");
+    assert_eq!(args, &vec!["--task".to_string(), "MCP_DATA".to_string()]);
+    assert_eq!(*classpath, 1, "jar 自己不在 -cp 里（拼命令行时才补）");
+    assert_eq!(fake.calls(), vec!["libraries", "java", "run"]);
+    let messages = h.messages();
+    assert!(
+        messages.iter().any(|m| m.contains("installer 处理器 1/1")),
+        "面板要看到当前处理器：{messages:?}"
+    );
+    assert!(
+        messages
+            .last()
+            .is_some_and(|m| m.contains("正在写入版本清单")),
+        "{messages:?}"
+    );
+    assert!(
+        h.log().contains("processors 完成：执行 1 步"),
+        "{}",
+        h.log()
+    );
+}
+
+#[test]
+fn stage_fails_loudly_without_a_usable_java() {
+    let h = Harness::new();
+    let installer = installer();
+    let profile = profile();
+    let input = input(&profile, &installer);
+    let mut fake = Fake::new();
+    fake.java = None;
+    let err = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel).unwrap_err();
+    assert!(err.contains("Java"), "{err}");
+    assert!(err.contains("托管目录"), "{err}");
+    assert_eq!(
+        fake.calls(),
+        vec!["libraries", "java"],
+        "没 Java 就不该起进程"
+    );
+    assert!(h.log().contains("失败："), "{}", h.log());
+}
+
+#[test]
+fn stage_fails_loudly_when_a_processor_exits_nonzero() {
+    let h = Harness::new();
+    let installer = installer();
+    let profile = profile();
+    let input = input(&profile, &installer);
+    let mut fake = Fake::new();
+    fake.run_error = Some(ProcessorError::failed(
+        "net.minecraftforge:installertools:1.3.0",
+        "1",
+        "java.lang.NoSuchMethodError",
+    ));
+    let err = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel).unwrap_err();
+    assert!(err.contains("processor_failed"), "{err}");
+    assert!(err.contains("NoSuchMethodError"), "{err}");
+    let log = h.log();
+    assert!(log.contains("失败："), "{log}");
+    assert!(log.contains("NoSuchMethodError"), "日志要能回溯：{log}");
+}
+
+#[test]
+fn stage_reports_incomplete_library_downloads() {
+    let h = Harness::new();
+    let installer = installer();
+    let profile = profile();
+    let input = input(&profile, &installer);
+    let mut fake = Fake::new();
+    fake.libraries_ok = false;
+    let err = stage(&h.env, &h.engine, &input, &fake, &h.reporter(), &h.cancel).unwrap_err();
+    assert!(err.contains("依赖库没下全"), "{err}");
+    assert!(err.contains("连接超时"), "{err}");
+    assert_eq!(fake.calls(), vec!["libraries"], "库没下全就别去选 Java");
+    let progress = h.meter.lock().expect("进度锁").progress.clone();
+    assert!(progress.files_total >= 2, "依赖库要计入文件总数");
+}

crates/app/src/host/install_tests.rs

@@ -1,24 +1,170 @@
 //! host/install.rs 的单测（拆文件守 400 行上限）。
 
 use std::path::PathBuf;
-use std::sync::atomic::AtomicBool;
+use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
-use std::sync::Arc;
+use std::sync::{Arc, Mutex};
 
 use unlucky_core::game::install::{FileOutcome, FileRole, FileStatus};
 
-use super::{run, supported, unsupported_reason};
+use super::{loader_label, run, supported, unsupported_reason, Job};
 use crate::dto::{CreateRequest, LoaderKind};
 use crate::host::env::HostEnv;
+use crate::host::install_journal::Journal;
+use crate::host::job::{channel, JobSender};
 use crate::host::meter::Meter;
 
+static SEQ: AtomicUsize = AtomicUsize::new(0);
+
+/// 一个装在临时根里的任务上下文（只走「联网前就返回」的用例）。
+struct Fixture {
+    dir: PathBuf,
+    env: HostEnv,
+    tx: JobSender,
+    meter: Arc<Mutex<Meter>>,
+    cancel: Arc<AtomicBool>,
+    journal: Journal,
+}
+
+impl Fixture {
+    fn new(request: &CreateRequest) -> Self {
+        let seq = SEQ.fetch_add(1, Ordering::SeqCst);
+        let dir =
+            std::env::temp_dir().join(format!("ull-host-install-{}-{seq}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&dir);
+        let env = HostEnv::at_root(&dir);
+        let journal = Journal::open(&env);
+        Self {
+            dir,
+            env,
+            tx: channel().0,
+            meter: Arc::new(Mutex::new(Meter::new(request))),
+            cancel: Arc::new(AtomicBool::new(false)),
+            journal,
+        }
+    }
+
+    fn job(&self) -> Job<'_> {
+        Job {
+            env: &self.env,
+            tx: &self.tx,
+            meter: &self.meter,
+            cancel: &self.cancel,
+            journal: &self.journal,
+        }
+    }
+}
+
+impl Drop for Fixture {
+    fn drop(&mut self) {
+        std::fs::remove_dir_all(&self.dir).ok();
+    }
+}
+
+fn request(loader: LoaderKind, version: &str) -> CreateRequest {
+    CreateRequest {
+        version: version.to_string(),
+        loader,
+        loader_version: String::new(),
+        name: String::new(),
+    }
+}
+
+/// 一个「刚下完」的文件结局（记账用）。
+fn downloaded(bytes: u64) -> FileOutcome {
+    FileOutcome {
+        role: FileRole::Library,
+        name: "lib.jar".to_string(),
+        dest: PathBuf::from("lib.jar"),
+        status: FileStatus::Downloaded,
+        bytes,
+        source: None,
+        failure: None,
+    }
+}
+
+#[test]
+fn progress_is_pre_accounted_across_segments_so_the_bar_never_snaps_to_full() {
+    // M45 r1 P2-2 的回归：处理器依赖库下完那一刻，面板曾显示 36/36 满格 + 3.4MB/10MB，
+    // 之后加载器库的 29 个文件才被计入 → 进度条从 100% 回落到 55% 再涨回去。
+    let request = request(LoaderKind::Forge, "1.20.1");
+    let mut meter = Meter::new(&request);
+
+    // 原版段：30 个文件全下完（install_vanilla 对总量是赋值，不是累加）
+    meter.progress.files_total = 30;
+    meter.progress.bytes_total = 3_000_000;
+    for _ in 0..30 {
+        meter.note(&downloaded(100_000));
+    }
+    assert!((meter.progress.ratio() - 1.0).abs() < f32::EPSILON);
+
+    // install_loader 的顺序：加载器库与处理器依赖库都在动手前一次预记账
+    meter.expect(29, 10_000_000);
+    meter.expect(36, 4_000_000);
+    assert_eq!(meter.progress.files_total, 95, "两段之和一次到位");
+    assert_eq!(
+        meter.progress.bytes_total, 17_000_000,
+        "字节是相加不是取最大"
+    );
+    assert!(
+        meter.progress.ratio() < 0.7,
+        "预记账后不能还停在满格：{}",
+        meter.progress.ratio()
+    );
+
+    // 处理器依赖库 36 个下完 → 仍没满格（加载器库还在后面）
+    for _ in 0..36 {
+        meter.note(&downloaded(110_000));
+    }
+    let ratio = meter.progress.ratio();
+    assert!(
+        (0.6..1.0).contains(&ratio),
+        "回落到中间态而不是满格：{ratio}"
+    );
+    assert!(
+        meter.progress.bytes_done < meter.progress.bytes_total,
+        "字节总量要覆盖已下载量：{}/{}",
+        meter.progress.bytes_done,
+        meter.progress.bytes_total
+    );
+
+    // 加载器库也下完 → 这时候才该是满格
+    for _ in 0..29 {
+        meter.note(&downloaded(340_000));
+    }
+    assert!((meter.progress.ratio() - 1.0).abs() < f32::EPSILON);
+}
+
 #[test]
 fn loader_support_matrix_is_explicit() {
-    assert!(supported(LoaderKind::Vanilla));
+    // M45 语义变更：Forge/NeoForge 从「GUI 显式拒装」扩进受支持集合（走 installer processors）。
-    assert!(supported(LoaderKind::Fabric));
+    for kind in [
-    assert!(supported(LoaderKind::Quilt));
+        LoaderKind::Vanilla,
-    assert!(!supported(LoaderKind::Forge));
+        LoaderKind::Fabric,
-    assert!(!supported(LoaderKind::NeoForge));
+        LoaderKind::Quilt,
-    assert!(unsupported_reason(LoaderKind::Forge).contains("ull install"));
+        LoaderKind::Forge,
+        LoaderKind::NeoForge,
+    ] {
+        assert!(supported(kind), "{} 应当受支持", kind.label());
+    }
+    // 这两家 core 侧还没有安装管线，仍然显式拒装并说清去哪装。
+    for kind in [LoaderKind::OptiFine, LoaderKind::LiteLoader] {
+        assert!(!supported(kind), "{} 不该被当成可装", kind.label());
+        let reason = unsupported_reason(kind);
+        assert!(reason.contains(kind.label()), "{reason}");
+        assert!(reason.contains("还没有接入"), "{reason}");
+    }
+}
+
+#[test]
+fn forge_install_is_no_longer_refused_at_the_door() {
+    // 旧文案是把用户赶去终端跑 `ull install`；M45 之后 GUI 与 CLI 同一条路径。
+    assert!(supported(LoaderKind::Forge));
+    assert!(supported(LoaderKind::NeoForge));
+    assert_eq!(loader_label(LoaderKind::Forge, "47.2.0"), "Forge 47.2.0");
+    assert_eq!(
+        loader_label(LoaderKind::NeoForge, "21.1.80"),
+        "NeoForge 21.1.80"
+    );
 }
 
 #[test]
@@ -57,30 +203,16 @@ fn meter_counts_files_and_skips_skipped_bytes() {
 
 #[test]
 fn empty_version_is_rejected_before_network() {
-    let dir = std::env::temp_dir().join(format!("ull-host-install-{}", std::process::id()));
+    let request = request(LoaderKind::Vanilla, "");
-    let _ = std::fs::remove_dir_all(&dir);
+    let fixture = Fixture::new(&request);
-    let env = HostEnv::at_root(&dir);
+    let err = run(&fixture.job(), &request).unwrap_err();
-    let (tx, _rx) = super::super::job::channel();
-    let request = CreateRequest {
-        version: String::new(),
-        loader: LoaderKind::Vanilla,
-        loader_version: String::new(),
-        name: String::new(),
-    };
-    let meter = Arc::new(std::sync::Mutex::new(Meter::new(&request)));
-    let cancel = Arc::new(AtomicBool::new(false));
-    let err = run(&env, &tx, &request, &meter, &cancel).unwrap_err();
     assert!(err.contains("没有选择版本"), "{err}");
+}
 
-    let forge = CreateRequest {
+#[test]
-        version: "1.20.1".to_string(),
+fn unsupported_loader_is_rejected_before_network() {
-        loader: LoaderKind::Forge,
+    let request = request(LoaderKind::OptiFine, "1.20.1");
-        ..request
+    let fixture = Fixture::new(&request);
-    };
+    let err = run(&fixture.job(), &request).unwrap_err();
-    let meter = Arc::new(std::sync::Mutex::new(Meter::new(&forge)));
+    assert!(err.contains("还没有接入"), "{err}");
-    let cancel = Arc::new(AtomicBool::new(false));
-    assert!(run(&env, &tx, &forge, &meter, &cancel)
-        .unwrap_err()
-        .contains("installer processors"));
-    std::fs::remove_dir_all(&dir).ok();
 }

crates/app/src/host/meter.rs

@@ -37,6 +37,16 @@ impl Meter {
         self.previous = None;
     }
 
+    /// 预记账一段待下载的文件（文件数 + 字节）。
+    ///
+    /// 一次安装可能分几段（原版 / 处理器依赖库 / 加载器库）：每段开工前都先记账，
+    /// 整条进度曲线才是单调的——某一段下完不会先到 100%，再因为下一段的文件被计入而回落。
+    pub(super) fn expect(&mut self, files: usize, bytes: u64) {
+        let files = u64::try_from(files).unwrap_or(u64::MAX);
+        self.progress.files_total = self.progress.files_total.saturating_add(files);
+        self.progress.bytes_total = self.progress.bytes_total.saturating_add(bytes);
+    }
+
     /// 记账一个文件的结局。
     pub(super) fn note(&mut self, outcome: &FileOutcome) {
         self.progress.files_done += 1;

crates/app/src/host/mod.rs

@@ -20,6 +20,8 @@ mod game;
 mod handle;
 mod identity;
 mod install;
+mod install_journal;
+mod install_processors;
 mod java;
 mod job;
 mod launch;

crates/app/src/screenshot.rs

@@ -24,6 +24,8 @@ pub struct ShotOptions {
     pub wizard: bool,
     /// 发起一次真实安装并停 `dwell_ms` 后取图（中间态）
     pub install: Option<String>,
+    /// 安装走哪个加载器（`--screenshot-loader forge`；缺省 = 原版）
+    pub loader: Option<String>,
     /// 发起一次真实启动并停 `dwell_ms` 后取图（中间态）
     pub launch: Option<String>,
     /// 打开一个日志会话（日志页有数据态：日志行 + 诊断卡片）
@@ -58,6 +60,7 @@ pub fn shot_options() -> Option<ShotOptions> {
         },
         wizard: flag("--screenshot-wizard"),
         install: value_of("--screenshot-install"),
+        loader: value_of("--screenshot-loader"),
         launch: value_of("--screenshot-launch"),
         session: value_of("--screenshot-session"),
         dwell_ms: value_of("--screenshot-dwell")
@@ -92,7 +95,7 @@ pub fn capture(app: &AppUi, options: &ShotOptions) -> Result<(), slint::Platform
     }
     if let Some(version) = &options.install {
         app.dispatch_and_run(
-            AppCommand::InstallVersion(version.clone()),
+            install_command(version, options.loader.as_deref()),
             options.dwell_ms,
         );
     }
@@ -115,6 +118,20 @@ pub fn capture(app: &AppUi, options: &ShotOptions) -> Result<(), slint::Platform
     Ok(())
 }
 
+/// 截图通道的安装指令：缺省原版，给了 `--screenshot-loader` 就走向导同一条路
+/// （`CreateInstance`），因此 Forge/NeoForge 的中间态也能取图。
+fn install_command(version: &str, loader: Option<&str>) -> AppCommand {
+    match loader.map(crate::dto::LoaderKind::parse) {
+        Some(Some(kind)) => AppCommand::CreateInstance(crate::dto::CreateRequest {
+            version: version.to_string(),
+            loader: kind,
+            loader_version: String::new(),
+            name: version.to_string(),
+        }),
+        _ => AppCommand::InstallVersion(version.to_string()),
+    }
+}
+
 /// `--flag` 是否存在。
 pub fn flag(name: &str) -> bool {
     std::env::args().skip(1).any(|arg| arg == name)

crates/app/ui/widgets/wizard.slint

@@ -196,8 +196,8 @@ export component NewInstanceWizard inherits Rectangle {
                     LoaderChoice { index: 0; label: "原版（Vanilla）"; hint: "不装加载器，最快最稳"; picked => { PageState.wizard-select-loader(0); } }
                     LoaderChoice { index: 1; label: "Fabric"; hint: "轻量模组加载器（GUI 可直接装）"; picked => { PageState.wizard-select-loader(1); } }
                     LoaderChoice { index: 2; label: "Quilt"; hint: "Fabric 的分支（GUI 可直接装）"; picked => { PageState.wizard-select-loader(2); } }
-                    LoaderChoice { index: 3; label: "Forge"; hint: "需要 installer processors：本轮请用 ull install"; picked => { PageState.wizard-select-loader(3); } }
+                    LoaderChoice { index: 3; label: "Forge"; hint: "需要 installer processors（首装会外调 java，约 1–3 分钟）"; picked => { PageState.wizard-select-loader(3); } }
-                    LoaderChoice { index: 4; label: "NeoForge"; hint: "需要 installer processors：本轮请用 ull install"; picked => { PageState.wizard-select-loader(4); } }
+                    LoaderChoice { index: 4; label: "NeoForge"; hint: "需要 installer processors（首装会外调 java，约 1–3 分钟）"; picked => { PageState.wizard-select-loader(4); } }
                 }
 
                 // ③ 名字