docs(#238): reference filed xlings root-cause issue openxlings/xlings#374

The install_packages multi-repo failure diagnostic, ledger, and CHANGELOG now
point at the concrete upstream tracking issue (openxlings/xlings#374) for the
root-cause fix. mcpp side remains diagnostics-only.

Author: Sunrisepeak

.agents/docs/2026-07-19-issues-230-243-batch-ledger-and-architecture-assessment.md

@@ -33,7 +33,7 @@
 |---|------|------|-----------|-----------|---------------|-------------|
 | **#230** | bug(win) | 🔒 已修(0.0.96) | scanner glob 走 symlink 逃逸 + 窄串转换抛异常→`__fastfail`→裸 127 | `scanner.cppm` symlink 守卫 + `.mcpp` prune;`src/main.cpp` 兜底 catch 返回 70 | 已根治(`df985df` / #231)。**动作:mcpp-index windows CI pin ≥0.0.96 复验后关闭** | 已发布 0.0.96 |
 | **#237** | 诊断缺口 | ✅ 已修待发 | xpkg 描述符 `mcpp` 段未知键在 **build 路径**静默丢弃(`xpkg parse` 才硬报错) | `xpkg.cppm:1324-1333`(else 分支入 `xpkgUnknownKeys`,build 不消费);消费点仅 `cmd_xpkg.cppm:122/186`;字段 `types.cppm:351` | build 时消费 `xpkgUnknownKeys` → 响亮告警(前向兼容,非硬错)+ `closest_known_xpkg_key`(封闭词表别名 + Levenshtein 回退)did-you-mean;在 `prepare.cppm` 描述符采纳点(funnel)发。单测 `XpkgUnknownKeys.CollectedAndDidYouMean` | `c20520b`(0.0.99) |
-| **#238** | bug | ⛔ **根因在 xlings**(mcpp 诊断✅) | xlings `install_packages` 多 index_repos(≥2)解析静默 exit 1 | mcpp 侧只:写多仓 `xlings.cppm:1109-1117`、shell-out `:1016/1022`、吞失败 `package_fetcher.cppm:343`(NDJSON 无 `error` 事件 `progress.cppm:23`);触发链 = #224 root `[indices]` 继承 | mcpp 侧**诊断已落地**(`00b66c5`):`read_seeded_index_repos`(空格容错解析,修了复用 compact `extract_string` 的假 0 仓 bug)+ `format_install_failure_diagnostic` 点名目标/仓清单/`≥2` 缺口提示,`captured_error()` 保留子进程输出,`MCPP_VERBOSE` 记原始调用。单测 `PmPackageFetcher.*`。**根因仍须落 xlings**:issue 草稿 `scratchpad/XLINGS_ISSUE_238.md` 待提交 openxlings/xlings | mcpp 诊断:`00b66c5`(0.0.99);根因:**xlings(待开 issue)** |
+| **#238** | bug | ⛔ **根因在 xlings**(mcpp 诊断✅) | xlings `install_packages` 多 index_repos(≥2)解析静默 exit 1 | mcpp 侧只:写多仓 `xlings.cppm:1109-1117`、shell-out `:1016/1022`、吞失败 `package_fetcher.cppm:343`(NDJSON 无 `error` 事件 `progress.cppm:23`);触发链 = #224 root `[indices]` 继承 | mcpp 侧**诊断已落地**(`00b66c5`):`read_seeded_index_repos`(空格容错解析,修了复用 compact `extract_string` 的假 0 仓 bug)+ `format_install_failure_diagnostic` 点名目标/仓清单/`≥2` 缺口提示,`captured_error()` 保留子进程输出,`MCPP_VERBOSE` 记原始调用。单测 `PmPackageFetcher.*`。**根因仍须落 xlings**:已提交 **openxlings/xlings#374** | mcpp 诊断:`00b66c5`(0.0.99);根因:**openxlings/xlings#374** |
 | **#239** | bug | 🟢 已修待发 | #233 消歧对越根/绝对 relPath 逃逸 `obj/` + `@` 撞 ninja 引号×#235 depfile | `plan.cppm` 消歧前缀 | `safe_object_prefix` 逐分量净化(去根/`.`丢/`..`→`__up`/非可移植→`_`),逐分量单射保 #233 唯一性 | `b7f32f6`(本 branch,0.0.98) |
 | **#240** | bug | 🟢 已修待发 | #233 消歧后 entry-main link 输入用陈旧扁平 `obj/main.o` | `plan.cppm` entry-main 独立重算 + census 盲区 | 对象路径收敛单一 `object_for`;entry-main 纳入普查 / 复用已扫描单元对象 | `b7f32f6`(本 branch,0.0.98) |
 | **#241** | enhancement | ✅ 已修待发 | build.mcpp G3 环境契约缺 per-dep 路径 | `build_program.cppm` contract_env(无 per-dep);sanitizer `sanitize_feature_env`;rerun hash;调用点 `prepare.cppm` 依赖 build.mcpp 站 + `dependencyEdges` 图;struct `BuildProgramEnv` | `BuildProgramEnv.depDirs` + `contract_env` 发 `MCPP_DEP_<NAME>_DIR`(同 feature sanitize,自动进 rerun hash)+ `mcpp::dep_dir()` 模块助手;用权威 consumer→dep 边图注入(覆盖 feature 激活依赖)。**根因**:消除包侧自导航 store 布局。作用域=依赖侧 build.mcpp(root 工程 build.mcpp 早于依赖解析,列后续)。e2e 125 | `df3750b`(0.0.99) |

CHANGELOG.md

@@ -15,7 +15,7 @@
 ### 修复
 
 - **xpkg 描述符 mcpp 段未知键 build 时静默忽略**(#237):`dependencies` 误写(正确键 `deps`)等未知键此前只有 `mcpp xpkg parse` 报,build 路径静默丢弃致依赖消失无诊断。现描述符被采纳为依赖时按键**响亮告警**并给 did-you-mean(封闭词表别名 + Levenshtein 回退);沿用 0.0.97 封闭文法先例,告警而非硬错以保前向兼容。
-- **多 index repo 下 `install_packages` 失败无诊断**(#238,**根因在 xlings**):裸 `fetch failed (exit 1)` 现重建为可操作诊断——点名目标、已配置 index repos 清单、`≥2` 仓的已知 xlings 解析缺口提示、保留子进程输出、`MCPP_VERBOSE=1` 看原始调用。**仅诊断改进**;多仓解析的根因修复须落在 openxlings/xlings(已另开 issue)。
+- **多 index repo 下 `install_packages` 失败无诊断**(#238,**根因在 xlings**):裸 `fetch failed (exit 1)` 现重建为可操作诊断——点名目标、已配置 index repos 清单、`≥2` 仓的已知 xlings 解析缺口提示、保留子进程输出、`MCPP_VERBOSE=1` 看原始调用。**仅诊断改进**;多仓解析的根因修复须落在 openxlings/xlings(已开 **openxlings/xlings#374**)。
 
 ### 设计(未实现,后续 PR)
 

src/pm/package_fetcher.cppm

@@ -342,7 +342,7 @@ format_install_failure_diagnostic(std::string_view target,
     if (indexRepos.size() >= 2) {
         msg += "; ≥2 project-level index repos is a known xlings resolution "
                "gap that can make install_packages silently exit non-zero "
-               "(mcpp #238; root cause in openxlings/xlings — the resolver "
+               "(mcpp #238; root cause openxlings/xlings#374 — the resolver "
                "does not report which repo/package failed)";
     }