fix: build the SONAME alias under explicit ninja goals (mcpp test), 0.0.107

A shared library that declares `soname` is written as bin/libX11.so but records
SONAME libX11.so.6. Both the linker resolving a transitive NEEDED and the loader
starting a binary look for the alias, never for the plain name — so the alias is
a prerequisite of anything that links the library, not a by-product of building
it.

It was modelled as a standalone ninja edge that nothing depends on, reachable
only through `default`. The 0.0.104 test batch (#274) made `mcpp test` pass
explicit goal targets so it could isolate per-test compiles, and that silently
stopped producing the alias. `mcpp build` and `mcpp run` drive `default` and
were unaffected, which is why this survived three releases: only a project
driven by `mcpp test` hits it.

The symptom lands three levels from the cause — a consumer failing to link with
`libX11.so: undefined reference to xcb_connect` (alongside `libxcb.so.1 ... not
found`), or a test binary exiting 127. mcpp-index CI has been failing this way
on gui-stack, imgui-module and imgui-window since 0.0.104; two probe PRs pinning
only MCPP_VERSION over unmodified descriptors reproduced it at both 0.0.104 and
0.0.106, which is what ruled out the package-identity migration as the cause.

Hang the alias off the consumer's implicit inputs, beside the .so it already
lists. Correct under `default` and under explicit goals alike, and it pulls in
nothing that was not already being built.

e2e 64 covered only `build` + `run` — precisely the two paths that still worked.
It now also runs `mcpp test` from a clean target dir and asserts the alias
exists; without the fix that test binary fails with exit 127.

Verified: unit 37/37; e2e 64 red before / green after; the three real mcpp-index
members pass with `mcpp test` alone (gui-stack 5/5, imgui-module 1/1,
imgui-window 1/1). Remaining local e2e failures (22, 98, 141) reproduce
identically on the released 0.0.106 binary under the same MCPP_HOME — they are
this machine's gcc 15.1.0, not this change.

Author: Sunrisepeak

CHANGELOG.md

@@ -3,6 +3,16 @@
 > 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/)。
 
+## [0.0.107] — 2026-07-25
+
+### 修复
+
+- **`mcpp test` 不再漏建共享库的 SONAME 别名(0.0.104 起的回归)。** 声明了 `soname` 的共享库产物写作 `bin/libX11.so`,但记录的 SONAME 是 `libX11.so.6`,链接器解析传递 `NEEDED`、加载器启动程序时找的都是后者 —— 别名不是附属产物,而是**任何链接该库的目标的前置条件**。此前别名是一条无人依赖的独立 ninja 边,只能经 `default` 到达;0.0.104 的 test 能力批次([#274](https://github.com/mcpp-community/mcpp/pull/274))让 `mcpp test` 改为显式指定 ninja 目标以隔离逐测试编译,于是这条边被静默跳过。
+
+  症状离根因很远,这也是它潜伏三个版本的原因:消费者链接期报 `libX11.so: undefined reference to xcb_connect`(伴 `libxcb.so.1 ... not found`),或测试二进制以 `exit 127` 退出。`mcpp build` / `mcpp run` 走 `default`,一直正常,所以只有以 `mcpp test` 驱动的工程会中招 —— mcpp-index 的 CI 正是如此,`gui-stack` / `imgui-module` / `imgui-window` 三个成员自 0.0.104 起持续失败。
+
+  修法是把别名挂到消费者的隐式输入上(`plan.cppm` 的 `append_direct_shared_deps`),与被链接的 `.so` 并列。无论 ninja 的目标是 `default` 还是某个测试二进制都会生成,且不会多编译任何东西。e2e 64 补了 `mcpp test` 一段覆盖此路径 —— 它此前只覆盖 `build` + `run`,正是缺口所在。
+
 ## [0.0.106] — 2026-07-25
 
 > 落地 **SPEC-001**(`docs/spec/package-identity.md`)—— 包身份的规范形态。0.0.105 为修 #278 引入的「`name` 必须写成完全限定名」是**编码约束而非设计规则**:它的唯一成因是 mcpp 构造安装目标时丢弃了已读到的字面 `name`、改用 `<ns>.<短名>` 重新渲染一遍。本版本改为直接使用字面值,规范形态回归 **`namespace` 承载层级、`name` 是单一原子段**。配套 xlings 0.4.69([#381](https://github.com/openxlings/xlings/issues/381),索引改按 `(namespace, name)` 建键)。

mcpp.toml

@@ -1,6 +1,6 @@
 [package]
 name        = "mcpp"
-version     = "0.0.106"
+version     = "0.0.107"
 description = "Modern C++ build & package management tool"
 license     = "Apache-2.0"
 authors     = ["mcpp-community"]

src/build/plan.cppm

@@ -727,6 +727,19 @@ make_plan(const mcpp::manifest::Manifest&         manifest,
             for (auto targetIndex : targetsIt->second) {
                 auto const& dep = sharedDepTargets[targetIndex];
                 lu.implicitInputs.push_back(dep.output);
+                // The SONAME alias is a prerequisite too, not a by-product: the
+                // library is written as bin/libX11.so but records SONAME
+                // libX11.so.6, so both the linker (resolving a transitive
+                // NEEDED) and the loader look for the alias, never for the
+                // plain name. Hanging it off the consumer keeps it correct
+                // under explicit ninja goals — `mcpp test` names the test
+                // binaries, and an alias edge that nothing depends on is
+                // reachable only through `default`, so it was silently skipped
+                // (0.0.104-0.0.106). The failure surfaced far away, as
+                // `libX11.so: undefined reference to xcb_connect` or a test
+                // exiting 127.
+                for (auto const& alias : runtime_aliases_for_target(dep.target))
+                    lu.implicitInputs.push_back(alias);
                 auto flags = shared_library_link_flags(dep.target);
                 lu.linkFlags.insert(lu.linkFlags.end(), flags.begin(), flags.end());
             }

src/toolchain/fingerprint.cppm

@@ -18,7 +18,7 @@ import mcpp.toolchain.detect;
 
 export namespace mcpp::toolchain {
 
-inline constexpr std::string_view MCPP_VERSION = "0.0.106";
+inline constexpr std::string_view MCPP_VERSION = "0.0.107";
 
 struct FingerprintInputs {
     Toolchain                       toolchain;

tests/e2e/64_shared_soname_runtime_alias.sh

@@ -95,4 +95,34 @@ readelf -d "$so" | grep -q 'Library soname: \[libdepShared.so.1\]' || {
     exit 1
 }
 
+# ── `mcpp test` must produce the alias too ──────────────────────────
+# The alias edge is reachable through ninja's `default`, which is what build
+# and run use. `mcpp test` names its goals explicitly (to isolate per-test
+# compiles), and from 0.0.104 to 0.0.106 that skipped the alias: a test binary
+# linked against libdepShared.so records NEEDED libdepShared.so.1 and then
+# exits 127 because the loader cannot find it. Start from a clean target dir so
+# only the test path can create it.
+mkdir -p tests
+cat > tests/linked_test.cpp <<'EOF'
+extern "C" int dep_shared_answer();
+
+int main() {
+    return dep_shared_answer() == 42 ? 0 : 1;
+}
+EOF
+
+rm -rf target
+"$MCPP" test > test.log 2>&1 || {
+    cat test.log
+    echo "mcpp test failed — the SONAME alias is a prerequisite of anything that links the library, not a by-product of the default target"
+    exit 1
+}
+
+alias_from_test="$(find target -name 'libdepShared.so.1' | head -1)"
+[ -n "$alias_from_test" ] || {
+    cat test.log
+    echo "mcpp test did not produce the ABI soname alias"
+    exit 1
+}
+
 echo "OK"