2026.9.27.1: e2e 804 for a path host tool's toolchain (#710); e2e 802 pins gcc; compatibility notes

e2e 804 builds a host tool reached through a plain path dependency, which
belongs to no workspace: without a [toolchain] of its own the tool is built
by the consumer's build-program compiler (llvm 22.1.8 in the test, while the
global default on Linux is gcc), and with one it is built by that compiler.
The released 2026.9.26.2 fails the first criterion; this branch passes both.

e2e 802 read libstdc++'s NEEDED entry under whatever toolchain the machine
defaults to, so it failed where the user's default is llvm; the manifest now
names gcc@16.1.0.

CHANGELOG: the changes an existing project can observe -- an unresolved
`workspace = true` is refused (#714), `sources = []` no longer infers a
library, and the build-database note code was renamed without an alias.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: speak-agent

CHANGELOG.md

@@ -52,8 +52,20 @@
 - `mcpp pack` 的 bundle-all 形态随 glibc 载荷复制 `lib/locale` 与 `lib/gconv`,启动脚本设置
   `LOCPATH` 与 `GCONV_PATH`(用户已设置时保留用户的值)。
 
+### 兼容性
+
+以下变化对已有工程可见:
+
+- 未解析的 `workspace = true` 此前静默成为空版本依赖,现在在加载时报错并点名条目(#714)。
+  修正方法是在工作空间根的 `[workspace.dependencies]` 中声明该包,或在条目上写明版本。
+- `[build] sources = []` 不再推断库目标。依赖这一推断的包在 `[targets]` 中声明库目标。
+- note 代码 `MCPP_BUILD_DATABASE_HOST_TOOL_UNBUILT` 由 `MCPP_BUILD_DATABASE_HOST_TOOL_DEFERRED`
+  取代,不保留旧代码。
+
 ### 其他
 
+- 测试:e2e 804 覆盖不属于任何工作空间的路径宿主工具包的工具链选择(#710);e2e 802 固定 gcc
+  工具链,使其断言不依赖机器的默认工具链。
 - ELF 检查以一次读取载入文件。此前逐字节读入,`mcpp test` 的链接后检查在测试程序较多时耗时
   数十分钟。
 - 规范:SPEC-001 v1.5、SPEC-004 v1.8、SPEC-005 v1.4、SPEC-007 v0.3。

tests/e2e/802_a_host_build_applies_its_host_row.sh

@@ -33,6 +33,11 @@ version = "0.1.0"
 standard   = "c++23"
 import_std = false
 
+# The criteria read libstdc++'s NEEDED entry, so the compiler is gcc whatever
+# the machine's default toolchain is.
+[toolchain]
+default = "gcc@16.1.0"
+
 [targets.cxxrt]
 kind = "bin"
 main = "src/main.cpp"

tests/e2e/804_a_path_host_tool_builds_with_its_chosen_toolchain.sh

@@ -0,0 +1,103 @@
+#!/usr/bin/env bash
+# requires: gcc elf
+# 804_a_path_host_tool_builds_with_its_chosen_toolchain.sh — mcpp#710.
+#
+# A host tool is built by one compiler, chosen once and recorded in the tool
+# store's key: `MCPP_TOOLCHAIN` when set, else the tool package's own
+# `[toolchain]` (its workspace's, for a member), else the compiler the
+# consumer compiles its build programs with. The member case has a unit test
+# (HostToolToolchain.AMemberToolReadsItsWorkspaceToolchain). This test covers
+# a tool reached through a plain path dependency, which belongs to no
+# workspace:
+#   1. a tool package that names no toolchain is built by the consumer's
+#      build-program compiler (llvm 22.1.8 here), not by the global default
+#      (gcc on Linux), which is what the sub-build used to resolve for itself;
+#   2. a tool package that names its own toolchain is built by it
+#      (gcc 16.1.0) while the consumer keeps llvm.
+# The compiler that produced the tool is read from its `.comment` section.
+set -e
+
+TMP=$(mktemp -d)
+trap "rm -rf $TMP" EXIT
+cd "$TMP"
+
+# An isolated home, so neither the user's default toolchain nor a stale tool
+# store entry decides the outcome. The registry is shared: toolchains are
+# expensive to install.
+export MCPP_HOME="$TMP/mcpphome"
+mkdir -p "$MCPP_HOME"
+if [ -d "$HOME/.mcpp/registry" ]; then
+    ln -s "$HOME/.mcpp/registry" "$MCPP_HOME/registry"
+fi
+unset MCPP_TOOLCHAIN
+
+mkdir -p toolpkg/src app/src
+write_tool() {   # $1 = the body of the tool's [toolchain] table, empty for none
+    cat > toolpkg/mcpp.toml <<'TOML'
+[package]
+name    = "toolpkg"
+version = "0.1.0"
+
+[targets.stamp]
+kind = "bin"
+main = "src/stamp.cpp"
+TOML
+    if [[ -n "$1" ]]; then
+        printf '\n[toolchain]\n%s\n' "$1" >> toolpkg/mcpp.toml
+    fi
+}
+cat > toolpkg/src/stamp.cpp <<'CPP'
+int main() { return 0; }
+CPP
+
+cat > app/mcpp.toml <<'TOML'
+[package]
+name    = "app"
+version = "0.1.0"
+
+[toolchain]
+default = "llvm@22.1.8"
+
+[dependencies]
+toolpkg = { path = "../toolpkg", tools = ["stamp"] }
+TOML
+cat > app/src/main.cpp <<'CPP'
+int main() {}
+CPP
+cat > app/build.mcpp <<'CPP'
+#include <string>
+import mcpp;
+int main() {
+    const char* tool = mcpp::dep_bin("toolpkg", "stamp");
+    if (!tool || !*tool) return 1;
+    mcpp::warning((std::string("TOOL=") + tool).c_str());
+}
+CPP
+
+tool_path() { sed -n 's/.*TOOL=//p' "$1" | tail -1; }
+
+# ── 1 ── no toolchain of its own: the consumer's build-program compiler
+write_tool ""
+(cd app && "$MCPP" build > ../b1.log 2>&1) || { cat b1.log; echo "FAIL: 1: build failed"; exit 1; }
+t="$(tool_path b1.log)"
+[[ -x "$t" ]] || { cat b1.log; echo "FAIL: 1: no tool binary at '$t'"; exit 1; }
+readelf -p .comment "$t" > c1.txt
+grep -q 'clang version 22\.1\.8' c1.txt || {
+    cat c1.txt; echo "FAIL: 1: the tool was not built by the consumer's llvm 22.1.8"; exit 1; }
+echo "ok: 1"
+
+# ── 2 ── its own toolchain: that one, whatever the consumer uses
+write_tool 'default = "gcc@16.1.0"'
+rm -rf app/target
+(cd app && "$MCPP" build > ../b2.log 2>&1) || { cat b2.log; echo "FAIL: 2: build failed"; exit 1; }
+t="$(tool_path b2.log)"
+[[ -x "$t" ]] || { cat b2.log; echo "FAIL: 2: no tool binary at '$t'"; exit 1; }
+readelf -p .comment "$t" > c2.txt
+grep -qE 'GCC: \(.*\) 16\.1\.0' c2.txt || {
+    cat c2.txt; echo "FAIL: 2: the tool's own [toolchain] was not used"; exit 1; }
+if grep -q 'clang version' c2.txt; then
+    cat c2.txt; echo "FAIL: 2: the tool was built by the consumer's clang"; exit 1
+fi
+echo "ok: 2"
+
+echo "PASS: 804_a_path_host_tool_builds_with_its_chosen_toolchain"