0.0.99: #243 feature dep/feat forwarding + #238 xlings 0.4.67 + #230 windows build.mcpp

.agents/docs/2026-07-19-issue-243-feature-forwarding-design.md

@@ -1,5 +1,7 @@
 # Issue #243 —— feature 依赖转发(`dep/feat`)设计
 
+> **⚠️ 实现路径已校正(见 [2026-07-19-v0.0.99-feature-forwarding-238-230-design.md](2026-07-19-v0.0.99-feature-forwarding-238-230-design.md))**:本文 §5 提出的 `requestedFeaturesByPkg` 累加器,在 0.0.98 已由 `0cca9e0` 的 `DependencyEdge` + `aggregatedRequest` 单一漏斗实现;#243 只需**把转发注入这个既有漏斗**(把转发 feature 追加进子依赖 push 前的 `spec.features`),不再新建平行结构。§1–§4、§6–§8 的语义分析仍然有效。
+>
 > 日期:2026-07-19
 > 基线:mcpp **0.0.98**(HEAD;`MCPP_VERSION = "0.0.98"` @ `src/toolchain/fingerprint.cppm:21`)
 > 范围:GitHub issue **#243** —— manifest `[features]` 的 (1) feature 条件依赖 与 (2) 依赖 feature **转发**(Cargo `dep/feat` 语法)。阻塞用例:opencv 模块包的 `opencv.dnn` 接口(一个 feature 既要拉入一个依赖、又要打开该依赖的某个 feature)。

.github/workflows/ci-linux-e2e.yml

@@ -158,7 +158,7 @@ jobs:
 
       - name: Bootstrap xlings + released mcpp
         run: |
-          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v0.4.62
+          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v0.4.67
           export PATH="$HOME/.xlings/subos/current/bin:$PATH"
           xlings update
           xlings install mcpp -y -g

.github/workflows/cross-build-test.yml

@@ -92,13 +92,17 @@ jobs:
       - name: Bootstrap mcpp via xlings
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          # 0.4.62 (current) — kept in lock-step with the xlings the release
-          # is built/bundled against (release.yml). A past 0.4.61 "download 404
+          # 0.4.67 (current) — kept in lock-step with the xlings the release
+          # is built/bundled against (release.yml). Bumped 0.4.62 -> 0.4.67 for
+          # mcpp#238: xlings 0.4.67 carries the multi-index_repo install fix
+          # (openxlings/xlings#374, commit cf9b60d5) so a workspace member with
+          # >=2 inherited index_repos installs uncached packages instead of
+          # failing silently. A past 0.4.61 "download 404
           # for mcpp@<pin>" was NOT a version bug — the xlings-res/mcpp GitHub
           # release assets were uploaded in a broken state (records present,
           # blobs missing → 404 on GET); re-uploaded clean. The stale-INDEX
           # half is handled by the marker-clear below.
-          XLINGS_VERSION: '0.4.62'
+          XLINGS_VERSION: '0.4.67'
         run: |
           tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
           curl -fsSL -o "/tmp/${tarball}" \
@@ -211,7 +215,7 @@ jobs:
       - name: Bootstrap mcpp via xlings
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.62'
+          XLINGS_VERSION: '0.4.67'
         run: |
           tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
           curl -fsSL -o "/tmp/${tarball}" \

.github/workflows/release.yml

@@ -96,7 +96,7 @@ jobs:
           # Pin xlings to a known-good version. The upstream install
           # script always grabs `latest` (no version override), so we
           # download + self-install manually to avoid broken releases.
-          XLINGS_VERSION: '0.4.62'
+          XLINGS_VERSION: '0.4.67'
         run: |
           if [ ! -x "$HOME/.xlings/subos/default/bin/xlings" ]; then
             tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
@@ -278,10 +278,10 @@ jobs:
           echo "version=$VERSION" >> "$GITHUB_OUTPUT"
           echo "tag=v$VERSION"    >> "$GITHUB_OUTPUT"
 
-      - name: Bootstrap mcpp via xlings (latest 0.4.62)
+      - name: Bootstrap mcpp via xlings (latest 0.4.67)
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.62'
+          XLINGS_VERSION: '0.4.67'
         run: |
           tarball="xlings-${XLINGS_VERSION}-linux-x86_64.tar.gz"
           curl -fsSL -o "/tmp/${tarball}" \
@@ -336,13 +336,13 @@ jobs:
           exec "$(dirname "$0")/bin/mcpp" "$@"
           LAUNCHER
           chmod +x "$STAGING/$WRAPPER/mcpp"
-          # Bundle the aarch64 xlings (0.4.62) so install.sh consumers on aarch64
+          # Bundle the aarch64 xlings (0.4.67) so install.sh consumers on aarch64
           # get an aarch64 xlings, not the x86_64 bootstrap one.
-          XLA="xlings-0.4.62-linux-aarch64.tar.gz"
+          XLA="xlings-0.4.67-linux-aarch64.tar.gz"
           if curl -fsSL -o "/tmp/$XLA" \
-               "https://github.com/openxlings/xlings/releases/download/v0.4.62/$XLA"; then
+               "https://github.com/openxlings/xlings/releases/download/v0.4.67/$XLA"; then
             tar -xzf "/tmp/$XLA" -C /tmp
-            XLBIN=$(find /tmp/xlings-0.4.62-linux-aarch64 -path '*/bin/xlings' -type f | head -1)
+            XLBIN=$(find /tmp/xlings-0.4.67-linux-aarch64 -path '*/bin/xlings' -type f | head -1)
             if [ -n "$XLBIN" ]; then
               mkdir -p "$STAGING/$WRAPPER/registry/bin"
               cp "$XLBIN" "$STAGING/$WRAPPER/registry/bin/xlings"
@@ -417,7 +417,7 @@ jobs:
       - name: Bootstrap mcpp via xlings
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.62'
+          XLINGS_VERSION: '0.4.67'
         run: |
           if [ ! -x "$HOME/.xlings/subos/default/bin/xlings" ]; then
             WORK=$(mktemp -d)
@@ -599,7 +599,7 @@ jobs:
         shell: bash
         env:
           XLINGS_NON_INTERACTIVE: '1'
-          XLINGS_VERSION: '0.4.62'
+          XLINGS_VERSION: '0.4.67'
         run: |
           WORK=$(mktemp -d)
           zipfile="xlings-${XLINGS_VERSION}-windows-x86_64.zip"

CHANGELOG.md

@@ -3,6 +3,23 @@
 > 本文件追踪 `mcpp-community/mcpp` 公开仓的版本演进。
 > 格式参考 [Keep a Changelog](https://keepachangelog.com/zh-CN/1.1.0/)。
 
+## [0.0.99] — 2026-07-19
+
+> #230–#243 批次收尾:#243 feature 转发落地(0.0.98 只出了设计)+ #238 根因修复随 xlings 0.4.67 vendored 入包 + #230 windows build.mcpp 次生面补齐。设计见 `.agents/docs/2026-07-19-v0.0.99-feature-forwarding-238-230-design.md`。
+
+### 新增
+
+- **feature 依赖 feature 转发 `dep/feat`**(#243,Cargo 平价):`[features]` 里含 `/` 的 token(或表格形专用 `forward = ["dep/feat"]` 键)表示"本包该 feature 激活时,顺带打开依赖 `dep` 的 `feat` feature"——一个 feature 既能本地拉源、又能开依赖的重档 feature,解阻塞模块包的可选模块接口(opencv-m 的 `import opencv.dnn;`:`dnn` 一档同时拉 `dnn.cppm` 源集并把 `compat.opencv` 以 `features=["dnn"]` 参与构建,而非对所有消费者全量 +309 TU)。收敛为**一数据模型 `featureForwards` 两文法**(TOML 与 xpkg 描述符共享唯一切分点 `split_feature_forward_token`);转发**注入 0.0.98 既有的 `aggregatedRequest` 依赖边漏斗**(在子依赖 push 进 worklist 前把转发 feature 并入其请求集),一处注入同时覆盖解析(`mergeActiveFeatureDeps` 拉被转发 feature 的条件依赖)与激活(边图 union → `apply()` 发宏/源集)两个消费点;沿 BFS 前向边天然**传递**(root→mid→leaf)。与 #242 `default-features = false` 加性组合(转发进显式请求集、不受默认门控影响),`mcpp build`/`mcpp test` 双路径一致。转发到未声明依赖 strict 报错 / 非 strict 告警;转发未声明的依赖 feature 复用既有 "does not declare requested feature" 门。单测 3 例、e2e 128(含双路径)。
+
+### 修复
+
+- **≥2 项目级 index_repo 时 `install_packages` 静默失败**(#238,**根因修复上游落地**):vendored xlings 由 0.4.62 升至 **0.4.67**,携 openxlings/xlings#374 的多仓安装修复(`fix(xim): surface multi-repo install failures + best-effort catalog`,commit `cf9b60d5`)。此前 workspace 根级 `[indices]` 继承(#224)× default 重定向(R6)组合会给每个成员播下 ≥2 个 `index_repos`,任一未缓存包安装裸 `exit 1` 无 error 事件;0.0.98 已在 mcpp 侧把它变成可操作诊断,0.0.99 随 bundle 带上真正的解析修复。发布/交叉构建/e2e 三处 workflow pin 同步 0.4.67。
+- **windows 下依赖/成员 `build.mcpp` 产物名缺 `.exe` 无法执行**(#230 次生面):`build.mcpp` 编出的宿主程序此前恒名 `build.mcpp.bin`;windows 的 `capture_exec` 走 cmd.exe,`.bin` 不在 PATHEXT 故无法按名启动 PE。现按平台取后缀(windows=`build.mcpp.exe`,其余保持 `.bin`,`is_windows` 为 constexpr,非 windows 字节不变)。此面在 0.0.96 的 scanner symlink-逃逸崩溃(`df985df`,裸 127 的真凶)修复后才会被 workspace 的 build-mcpp 成员在 windows 走到。
+
+### 备注
+
+- #230 主因(scanner glob 顺 `.mcpp/.xlings` symlink 逃逸进 vendored 索引、CJK 文件名触发 MSVC 窄串转换抛异常→`__fastfail`→裸 127)已于 0.0.96 根治并在 0.0.98/0.0.99 在库;`src/main.cpp` 顶层 catch 兜底(未捕获异常→exit 70,不再裸 127)。0.0.99 补齐 build.mcpp 次生面后,mcpp-index 的 workspace(windows)CI 从临时钉回的 0.0.94 升到 0.0.99 复验全绿即关闭。
+
 ## [0.0.98] — 2026-07-19
 
 > #230–#243 批次(单 PR 统一发布,逐 commit):#233 对象路径消歧的两个后续缺口(#239/#240,解阻塞 mcpplibs #79 opencv 收录)+ #237/#241/#242 根因级实现 + #238 mcpp 侧诊断(根因在 openxlings/xlings#374)+ #243 设计。总账 + 架构评估见 `.agents/docs/2026-07-19-issues-230-243-batch-ledger-and-architecture-assessment.md`;各设计文档见 `.agents/docs/2026-07-19-*`。

mcpp.toml

@@ -1,6 +1,6 @@
 [package]
 name        = "mcpp"
-version     = "0.0.98"
+version     = "0.0.99"
 description = "Modern C++ build & package management tool"
 license     = "Apache-2.0"
 authors     = ["mcpp-community"]

src/build/build_program.cppm

@@ -536,7 +536,14 @@ std::expected<void, std::string> run_build_program(
     }
 
     fs::create_directories(outDir, ec);   // creates bdir too
-    fs::path bin = bdir / "build.mcpp.bin";
+    // #230: on Windows the capture_exec shell is cmd.exe, which can only launch
+    // a PE by an executable extension — a bare `.bin` is not in PATHEXT and
+    // fails to run. Name the compiled program `.exe` there; other platforms keep
+    // `.bin` (cosmetic — bdir is separate from the `.mcpp` source). Surfaces
+    // once a workspace build.mcpp member is reached on Windows, after the
+    // scanner symlink-escape crash fix (df985df) stops masking it as exit 127.
+    fs::path bin = bdir / (mcpp::platform::is_windows
+                               ? "build.mcpp.exe" : "build.mcpp.bin");
 
     // ── Compile build.mcpp with the host toolchain ──────────────────────────
     std::string std_flag = "-std=" + std::string(cppStandard.empty() ? "c++23" : cppStandard);

src/build/prepare.cppm

@@ -2154,31 +2154,79 @@ prepare_build(bool print_fingerprint,
         }
     };
 
+    // #243: dep/feat forwarding. When a resolved package's feature F is active,
+    // it may forward features to its dependencies (Cargo `[features] F =
+    // ["dep/feat"]`). Injecting the forwarded feature into the child's request
+    // BEFORE the child is pushed onto the worklist makes BOTH consumption points
+    // observe it: resolution (mergeActiveFeatureDeps reads the child's
+    // spec.features) and activation (recordDependencyEdge stores spec.features on
+    // the P->D edge, which aggregatedRequest unions and apply() activates).
+    // Transitive forwarding rides the BFS forward edge (root -> mid -> leaf).
+    auto injectForwards = [](const mcpp::manifest::Manifest& parent,
+                             const std::vector<std::string>& parentActive,
+                             const std::string& childKey,
+                             mcpp::manifest::DependencySpec& childSpec) {
+        if (parent.featureForwards.empty()) return;
+        for (auto const& f : parentActive) {
+            auto it = parent.featureForwards.find(f);
+            if (it == parent.featureForwards.end()) continue;
+            for (auto const& [depKey, depFeat] : it->second) {
+                if (depKey != childKey) continue;
+                if (std::find(childSpec.features.begin(), childSpec.features.end(),
+                              depFeat) == childSpec.features.end())
+                    childSpec.features.push_back(depFeat);
+            }
+        }
+    };
+    // #243: a forward whose active feature targets a dependency that is not
+    // declared (in [dependencies], [dev-dependencies], or an active
+    // [feature-deps] already folded into `dependencies`) is a manifest bug —
+    // name it instead of silently dropping. Only active features' forwards are
+    // checked (lazy, like the unknown-requested-feature gate at ~2875).
+    auto validateForwards = [&](const mcpp::manifest::Manifest& parent,
+                                const std::vector<std::string>& parentActive,
+                                std::string_view parentName)
+        -> std::expected<void, std::string> {
+        for (auto const& f : parentActive) {
+            auto it = parent.featureForwards.find(f);
+            if (it == parent.featureForwards.end()) continue;
+            for (auto const& [depKey, depFeat] : it->second) {
+                if (parent.dependencies.contains(depKey)
+                    || parent.devDependencies.contains(depKey)) continue;
+                auto msg = std::format(
+                    "feature '{}' of '{}' forwards to dependency '{}' (as "
+                    "'{}/{}') which is not declared in [dependencies] or "
+                    "[feature-deps]", f, parentName, depKey, depKey, depFeat);
+                if (overrides.strict) return std::unexpected(msg);
+                std::println(stderr, "warning: {}", msg);
+            }
+        }
+        return {};
+    };
+
     // Pull the root package's active feature-deps into its dependency set before
     // seeding, so `mcpp build --features X` resolves X's optional deps.
-    {
-        std::vector<std::string> rootReq;
-        for (std::size_t p = 0; p < overrides.features.size();) {
-            auto c = overrides.features.find_first_of(", ", p);
-            auto tok = overrides.features.substr(
-                p, c == std::string::npos ? std::string::npos : c - p);
-            if (!tok.empty()) rootReq.push_back(tok);
-            if (c == std::string::npos) break;
-            p = c + 1;
-        }
-        mergeActiveFeatureDeps(*m, rootReq);
-    }
+    std::vector<std::string> rootReq = parse_feature_request(overrides.features);
+    mergeActiveFeatureDeps(*m, rootReq);
+    // #243: the root's active features may forward features to its direct deps.
+    std::vector<std::string> rootActive = feature_closure(*m, rootReq, true);
+    if (auto fe = validateForwards(*m, rootActive, m->package.name); !fe)
+        return std::unexpected(fe.error());
 
     // Seed the worklist from the main manifest. Dev-deps only when the
     // caller wants them; they're never propagated transitively.
     const std::string mainPkgLabel = m->package.name;
     for (auto& [n, s] : m->dependencies) {
-        worklist.push_back({n, s, mainPkgLabel, s.version, kMainConsumer, {}});
+        auto req = s;
+        injectForwards(*m, rootActive, n, req);
+        worklist.push_back({n, req, mainPkgLabel, req.version, kMainConsumer, {}});
     }
     if (includeDevDeps) {
         for (auto& [n, s] : m->devDependencies) {
-            worklist.push_back({n, s, mainPkgLabel + " (dev-dep)",
-                                s.version, kMainConsumer, {}});
+            auto req = s;
+            injectForwards(*m, rootActive, n, req);
+            worklist.push_back({n, req, mainPkgLabel + " (dev-dep)",
+                                req.version, kMainConsumer, {}});
         }
     }
 
@@ -2683,9 +2731,22 @@ prepare_build(bool print_fingerprint,
             key.shortName,
             sourceKind == "version" ? spec.version : sourceKind);
         const std::size_t selfIdx = dep_manifests.size() - 1;
+        // #243: forward this dep's active features to ITS children before they
+        // are pushed (transitive dep->dep forwarding rides the BFS forward
+        // edge). Uses the SAME closure inputs as mergeActiveFeatureDeps above
+        // (this edge's spec.features, already carrying any forward injected by
+        // this dep's own consumer, + defaultFeatures), so activation agrees
+        // with resolution.
+        auto depActive = feature_closure(*dep_manifests.back(), spec.features,
+                                         spec.defaultFeatures);
+        if (auto fe = validateForwards(*dep_manifests.back(), depActive,
+                                       dep_manifests.back()->package.name); !fe)
+            return std::unexpected(fe.error());
         for (auto& [child_name, child_spec] : dep_manifests.back()->dependencies) {
-            worklist.push_back({child_name, child_spec, thisDepLabel,
-                                child_spec.version, selfIdx, dep_root});
+            auto childReq = child_spec;
+            injectForwards(*dep_manifests.back(), depActive, child_name, childReq);
+            worklist.push_back({child_name, childReq, thisDepLabel,
+                                childReq.version, selfIdx, dep_root});
         }
     }
 

src/manifest/toml.cppm

@@ -210,12 +210,18 @@ std::expected<Manifest, ManifestError> parse_string(std::string_view content,
         };
         for (auto& [fname, fval] : *features_table) {
             std::vector<std::string> implied;
+            std::vector<std::string> forwardTokens;
             if (fval.is_array()) {
                 for (auto& v : fval.as_array())
                     if (v.is_string()) implied.push_back(v.as_string());
             } else if (fval.is_table()) {
                 auto& ft = fval.as_table();
                 read_str_array(ft, "implies", implied);
+                // #243: a feature may forward features to its dependencies
+                // (Cargo `dep/feat`). Two equivalent spellings, one data model:
+                // `dep/feat` tokens mixed into `implies` (Cargo parity), or a
+                // dedicated self-documenting `forward = ["dep/feat", ...]` key.
+                read_str_array(ft, "forward", forwardTokens);
                 std::vector<std::string> defs;
                 read_str_array(ft, "defines", defs);
                 if (!defs.empty()) m.buildConfig.featureDefines[fname] = std::move(defs);
@@ -232,7 +238,20 @@ std::expected<Manifest, ManifestError> parse_string(std::string_view content,
                 if (!reqs.empty())  m.featureRequires[fname] = std::move(reqs);
                 if (!provs.empty()) m.featureProvides[fname] = std::move(provs);
             }
-            m.featuresMap[fname] = std::move(implied);
+            // #243: split `dep/feat` tokens out of `implies` into featureForwards
+            // (raw depKey shares the `dependencies`/`featureDeps` keyspace); the
+            // dedicated `forward` key is always forwards. Plain names stay implies.
+            std::vector<std::string> localImplies;
+            for (auto& tok : implied) {
+                if (auto fwd = mcpp::pm::split_feature_forward_token(tok))
+                    m.featureForwards[fname].push_back(std::move(*fwd));
+                else
+                    localImplies.push_back(std::move(tok));
+            }
+            for (auto& tok : forwardTokens)
+                if (auto fwd = mcpp::pm::split_feature_forward_token(tok))
+                    m.featureForwards[fname].push_back(std::move(*fwd));
+            m.featuresMap[fname] = std::move(localImplies);
         }
     }