docs: #722 completed, the function-size gate in CI (changelog, 13.6)

Author: speak-agent

.agents/docs/2026-09-27-eight-reports-by-home-and-one-optimisation-plan.md

@@ -1392,3 +1392,19 @@ there on both binaries, for reasons of the environment (an unset `MCPP_HOME`;
 the machine's default toolchain), so the differential read them as unchanged.
 A test that fails on both sides measures nothing about the change; its reading
 has to come from an environment in which it passes, which here is CI.
+
+**#722, completed after the first CI run.** The first pass split the seven named
+functions and three more the gate found (10 findings at the base, 6 after it).
+The second pass split the six that remained (`step6_provision_host_tools`,
+`loadVersionDep`, `phase11_scan`, `step1_target_and_static_overrides`,
+`phase2_define_toolchain_resolver`, `step9_kernel_abi_interfaces_and_requirements`),
+each with a phase-local context struct where several of its steps share locals.
+Readings on the final tree: the gate reports no function over 400 lines; the
+seven fixtures are byte-identical to the pre-split binary; AddressSanitizer
+reports nothing over the fixtures and a 20-script e2e subset; the unit suite
+passes. The gate runs in `ci-linux.yml`'s LLVM toolchain job after mcpp builds
+itself with llvm@20.1.7, with clang-tidy from `xim:llvm-tools` at the version
+that wrote the compile database, because it reads that clang's BMIs. The merge
+of the first pass took `plan.cpp` to 2,505 lines, over the file gate; the
+records half of P13 (`mcpp.lock`, `resolution.json`) moved to `records.cpp`,
+byte-identical on the same fixtures.

CHANGELOG.md

@@ -68,7 +68,10 @@
 ### 内部
 
 - **`src/build/prepare/` 的阶段函数按其小节拆分(#722)。** 代码逐字移动,不改变语句顺序;七个
-  夹具的 `resolution.json`、`build.ninja` 与构建数据库输出与拆分前逐字节相同。
+  夹具的 `resolution.json`、`build.ninja` 与构建数据库输出与拆分前逐字节相同。该目录下没有超过
+  400 行的函数:`.github/tools/check_function_sizes.sh` 以 clang-tidy 的 `readability-function-size`
+  在 LLVM 自举构建之后检查,拆分前报告 10 处。`mcpp.lock` 与 `resolution.json` 的写入移入
+  `records.cpp`。
 - **xlings 固定版本为 2026.9.28.1。** 该版本的 interface 协议为 1.2:`update_packages` 按阶段发出
   进度事件,interface 能力运行期间写到标准输出的文本不再混入事件流(openxlings/xlings#625)。