release: 2026.10.26.1 -- the control contract, concurrency, one C++ runtime per process (#838, #839)

.agents/docs/2026-10-26-control-contract-runtime-and-ide-ecosystem-repro.sh

@@ -0,0 +1,202 @@
+#!/usr/bin/env bash
+# Reproductions for .agents/docs/2026-10-26-control-contract-runtime-and-ide-ecosystem-design.md
+#
+# Scenarios (each prints and never asserts; run one with SCENARIO=<letter>):
+#   A  #839  concurrent cold builds of one configuration (E4) and of two configurations (E5)
+#   B  #838  split exception ABI without sycl (E1), and the link-order fix (E2)
+#   C        query/build latency baseline (E8) -- needs hyperfine
+#   D        xlings interface fixed wait (E9)  -- needs strace
+#   E        cache list cost (E10)              -- needs strace
+#   F        clang + libstdc++ import std, cross-.so catch (E14, E15)
+#   G        mcpp run exit status (E16)
+#   H  X2    unrecorded projection entry refused (E12, E13) -- FRESH=1 builds a fresh home (downloads gcc twice)
+#   I        SYCL units vs the runtime collision set and foreign typeinfo (E19, E20) -- needs xim:dpcpp 7.1.0;
+#            TENSORVIA=<checkout> adds Tensorvia's device units
+#
+# Uses only payloads already in the mcpp home, except H with FRESH=1.
+set -u
+M=${MCPP:-$HOME/.xlings/data/xpkgs/xim-x-mcpp/2026.10.24.1/bin/mcpp}
+R=${MCPP_HOME:-$HOME/.mcpp}/registry/data/xpkgs
+W=${WORK:-/tmp/mcpp-ecosystem-repro}
+export MCPP_JOBS=${MCPP_JOBS:-8}
+mkdir -p "$W"
+want() { [ -z "${SCENARIO:-}" ] || [ "$SCENARIO" = "$1" ]; }
+
+modules_project() {   # $1 = dir
+    rm -rf "$1"; mkdir -p "$1/src"
+    printf '[package]\nname = "lk"\nversion = "0.1.0"\nstandard = "c++23"\n[toolchain]\ndefault = "gcc@16.1.0"\n' > "$1/mcpp.toml"
+    for i in $(seq 1 24); do
+        printf 'export module m%d;\nimport std;\nexport int f%d(){ std::vector<int> v(%d); return (int)v.size(); }\n' $i $i $i > "$1/src/m$i.cppm"
+    done
+    { echo 'import std;'; for i in $(seq 1 24); do echo "import m$i;"; done
+      echo 'int main(){ std::println("{}", f1()+f24()); }'; } > "$1/src/main.cpp"
+}
+
+if want A; then
+    echo "===== A: concurrent builds (#839)"
+    modules_project "$W/a"; cd "$W/a"
+    for r in 1 2 3 4 5; do
+        rm -rf target
+        ( nice -n 10 "$M" build >"$W/a1.log" 2>&1; echo $? >"$W/a1.rc" ) &
+        ( sleep 0.$r; nice -n 10 "$M" build >"$W/a2.log" 2>&1; echo $? >"$W/a2.rc" ) &
+        wait
+        echo "round $r: rc=$(cat "$W/a1.rc"),$(cat "$W/a2.rc")  $(grep -h -m1 'error:' "$W/a1.log" "$W/a2.log" | head -1)"
+    done
+    ( "$M" build >/dev/null 2>&1; echo "dev rc=$?" ) & ( "$M" build --release >/dev/null 2>&1; echo "release rc=$?" ) & wait
+fi
+
+if want B; then
+    echo "===== B: split exception ABI (#838)"
+    G=$R/xim-x-gcc/16.1.0/lib64
+    rm -rf "$W/b"; mkdir -p "$W/b/src" "$W/b/tests"; cd "$W/b"
+    cat > mcpp.toml <<EOF
+[package]
+name     = "xrt"
+version  = "0.1.0"
+standard = "c++23"
+[toolchain]
+default = "llvm@22.1.8"
+[lib]
+path = "src/xrt.cppm"
+[targets.xrt]
+kind = "shared"
+[build]
+ldflags = ["-L$G", "-l:libstdc++.so.6"]
+EOF
+    printf 'export module xrt;\nimport std;\nexport namespace xrt { int checked(int v) { if (v < 0) throw std::runtime_error("negative"); return v * 2; } }\n' > src/xrt.cppm
+    cat > tests/catch.cpp <<'EOF'
+import std;
+import xrt;
+int main() {
+    auto ep = std::make_exception_ptr(std::logic_error("x"));   // a libc++abi-only entry point
+    try { xrt::checked(-1); }
+    catch (const std::exception& e) { std::println("caught as std::exception: {}", e.what()); return 0; }
+    catch (...)                     { std::println("std::exception missed -> (...)"); return 1; }
+}
+EOF
+    nice -n 10 "$M" test 2>&1 | tail -3
+    D=$(dirname "$(find target -name build.ninja | head -1)"); LL=$R/xim-x-llvm/22.1.8/bin
+    "$LL/llvm-nm" -D --undefined-only "$D/bin/catch" | grep -E "__cxa_throw|__gxx_personality|_ZTISt13runtime_error"
+    echo "-- relink with the toolchain's own runtime first (E2)"
+    cd "$D"
+    NJ=$(command -v ninja || find "$R" -name ninja -type f -perm -u+x | head -1)
+    CMD=$("$NJ" -t commands bin/catch | tail -1)
+    LIBS="$R/xim-x-llvm/22.1.8/lib/x86_64-unknown-linux-gnu/libc++.a $R/xim-x-llvm/22.1.8/lib/x86_64-unknown-linux-gnu/libc++abi.a"
+    FIXED=$(echo "$CMD" | sed "s# -l:libstdc++.so.6# $LIBS -l:libstdc++.so.6#; s#-o bin/catch#-o bin/catch.fixed#; s#bin/catch.rsp#bin/catch.fixed.rsp#")
+    printf 'obj/xrt.m.o\nobj/catch.o\nobj/std.o\n' > bin/catch.fixed.rsp
+    eval "$FIXED" && ./bin/catch.fixed; echo "rc=$?  GLIBCXX imports: $("$LL/llvm-nm" -D --undefined-only bin/catch.fixed | grep -c GLIBCXX)"
+fi
+
+if want C; then
+    echo "===== C: latency baseline"
+    modules_project "$W/c"; cd "$W/c"; "$M" build >/dev/null 2>&1
+    hyperfine -N --warmup 2 --runs 8 "$M --version" "$M --protocol-version" "$M build" "$M run" \
+        "$M emit build-database --format json" "$M self env --format json" \
+        "$M cache list --format json" "$M toolchain list --format json" 2>&1 | grep -E "^Benchmark|Time \(mean"
+fi
+
+if want D; then
+    echo "===== D: xlings interface fixed wait"
+    X=${MCPP_HOME:-$HOME/.mcpp}/registry/bin/xlings
+    cd "${MCPP_HOME:-$HOME/.mcpp}/registry"
+    for a in '--version' 'payload_status --args {"targets":["xim:gcc@16.1.0"]}'; do
+        s=$(date +%s%N); env -u XLINGS_PROJECT_DIR -u XLINGS_ACTIVE_SUBOS XLINGS_HOME="$PWD" "$X" interface $a >/dev/null 2>&1
+        echo "interface ${a%% *}: $(( ($(date +%s%N)-s)/1000000 )) ms"
+    done
+    strace -f -tt -T -e trace=nanosleep,clock_nanosleep,futex,poll -o "$W/d.txt" \
+        env -u XLINGS_PROJECT_DIR -u XLINGS_ACTIVE_SUBOS XLINGS_HOME="$PWD" "$X" interface payload_status --args '{"targets":["xim:gcc@16.1.0"]}' >/dev/null 2>&1
+    awk '{ if (match($0, /<([0-9.]+)>$/, m) && m[1] > 0.05) print }' "$W/d.txt"
+fi
+
+if want E; then
+    echo "===== E: cache list"
+    C=${MCPP_HOME:-$HOME/.mcpp}/build-cache
+    echo "files: $(find "$C" -type f | wc -l)"
+    strace -c -f -o "$W/e.txt" "$M" cache list --format json >/dev/null 2>&1; head -8 "$W/e.txt"
+fi
+
+if want F; then
+    echo "===== F: clang + libstdc++"
+    CXX=$R/xim-x-llvm/22.1.8/bin/clang++; GLIBC=$R/xim-x-glibc/2.44.3; UAPI=$R/xim-x-linux-headers/5.11.1
+    for V in 15.1.0 16.1.0; do
+        G=$R/xim-x-gcc/$V; GID=$(ls -d "$G"/lib/gcc/x86_64-linux-gnu/* | head -1)
+        rm -rf "$W/f-$V"; mkdir -p "$W/f-$V"; cd "$W/f-$V"
+        INC="-nostdinc++ -isystem $G/include/c++/$V -isystem $G/include/c++/$V/x86_64-linux-gnu -isystem $G/include/c++/$V/backward -nostdlibinc -isystem $GLIBC/include -isystem $UAPI/include"
+        C="--no-default-config -std=c++23 --gcc-install-dir=$GID $INC"
+        L="--no-default-config -stdlib=libstdc++ --gcc-install-dir=$GID -fuse-ld=lld --rtlib=libgcc --unwindlib=libgcc -L$G/lib64 -Wl,-rpath,$G/lib64 -B$GLIBC/lib64 -L$GLIBC/lib64 -Wl,-rpath,$GLIBC/lib64 -Wl,--dynamic-linker=$GLIBC/lib64/ld-linux-x86-64.so.2"
+        "$CXX" $C -Wno-reserved-module-identifier --precompile -x c++-module "$G/include/c++/$V/bits/std.cc" -o std.pcm 2>/dev/null; echo "[$V] std.pcm rc=$?"
+        "$CXX" $C -c std.pcm -o std.o 2>/dev/null
+        printf 'import std;\nint main(){ std::vector<int> v{3,1,2}; std::ranges::sort(v); std::println("{} {}", v, std::format("{:.2f}", 3.14159));\n try { throw std::runtime_error("boom"); } catch (const std::exception& e) { std::println("caught: {}", e.what()); }\n std::jthread t([]{ std::println("thread ok"); }); }\n' > main.cpp
+        "$CXX" $C -fmodule-file=std=std.pcm -c main.cpp -o main.o && "$CXX" $L main.o std.o -o app && ./app; echo "[$V] run rc=$?"
+        printf '#include <stdexcept>\nint checked(int v){ if (v<0) throw std::runtime_error("negative (from .so)"); return v*2; }\n' > lib.cpp
+        printf 'import std;\nint checked(int);\nint main(){ try { checked(-1); } catch (const std::exception& e) { std::println("caught across .so: {}", e.what()); return 0; } catch (...) { return 1; } }\n' > use.cpp
+        "$CXX" $C -fPIC -c lib.cpp -o lib.o && "$CXX" $L -shared lib.o -o libthrow.so \
+            && "$CXX" $C -fmodule-file=std=std.pcm -c use.cpp -o use.o && "$CXX" $L use.o std.o -L. -lthrow -Wl,-rpath,"$PWD" -o use && ./use
+        echo "[$V] cross-.so rc=$?"
+    done
+fi
+
+if want G; then
+    echo "===== G: mcpp run exit status"
+    rm -rf "$W/g"; mkdir -p "$W/g/src"; cd "$W/g"
+    printf '[package]\nname = "rc"\nversion = "0.1.0"\nstandard = "c++23"\n' > mcpp.toml
+    printf 'import std;\nint main(int argc, char* argv[]) {\n std::string_view m = argc > 1 ? argv[1] : "ok";\n if (m == "exit") return std::atoi(argv[2]);\n if (m == "throw") throw std::runtime_error("boom");\n if (m == "abort") std::abort();\n if (m == "segv") std::raise(11);\n return 0; }\n' > src/main.cpp
+    "$M" build >/dev/null 2>&1
+    for a in "ok" "exit 3" "exit 255" "exit 256" "throw" "abort" "segv"; do
+        "$M" run -- $a >/dev/null 2>&1; echo "mcpp run -- $a => $?"
+    done
+fi
+
+if want H; then
+    echo "===== H: X2 unrecorded projection entry"
+    if [ "${FRESH:-0}" = 1 ]; then
+        H=$W/h-home; rm -rf "$H" "$W/h1"; mkdir -p "$W/h1/src"
+        printf '[package]\nname = "p1"\nversion = "0.1.0"\nstandard = "c++23"\n[toolchain]\ndefault = "gcc@16.1.0"\n[xlings.workspace]\n"xim:gcc" = "15.1.0"\n' > "$W/h1/mcpp.toml"
+        printf 'import std;\nint main(){ std::println("p1"); }\n' > "$W/h1/src/main.cpp"
+        (cd "$W/h1" && MCPP_HOME=$H nice -n 10 "$M" build 2>&1 | tail -2)
+        X=$H/registry/bin/xlings; E="env -u XLINGS_PROJECT_DIR -u XLINGS_ACTIVE_SUBOS XLINGS_HOME=$H/registry"
+        cd "$H/registry"
+        $E "$X" use gcc 15.1.0 2>&1 | tail -1; $E "$X" use gcc 16.1.0 2>&1 | tail -1   # E12: both succeed
+        cp subos/default/.xlings.json "$W/h-ledger.bak"
+        python3 - "$H/registry/subos/default/.xlings.json" <<'EOF'
+import json, sys
+p = sys.argv[1]; d = json.load(open(p))
+def strip(o):
+    if isinstance(o, dict):
+        for k in [k for k in o if k in ("libatomic.so", "libatomic.so.1")]: del o[k]
+        for v in o.values(): strip(v)
+    elif isinstance(o, list):
+        for v in o: strip(v)
+strip(d); json.dump(d, open(p, "w"), indent=2)
+EOF
+        $E "$X" use gcc 15.1.0 2>&1 | tail -1                                                # E13: refused
+        cp "$W/h-ledger.bak" subos/default/.xlings.json
+    else
+        echo "set FRESH=1 to build a fresh home (downloads gcc 16.1.0 and 15.1.0)"
+    fi
+fi
+
+if want I; then
+    echo "===== I: SYCL units vs the collision set (E19, E20)"
+    DX=$R/xim-x-dpcpp/7.1.0/bin/clang++; G=$R/xim-x-gcc/15.1.0; GID=$(ls -d "$G"/lib/gcc/x86_64-linux-gnu/* | head -1)
+    GLIBC=$R/xim-x-glibc/2.44.3; UAPI=$(ls -d "$R"/xim-x-linux-headers/* | head -1); LL=$R/xim-x-llvm/22.1.8; NM=$LL/bin/llvm-nm
+    P=$R/mcpp-x-plugins/0.19.1/mcpp-plugins-0.19.1/tests/sycl-consumer
+    rm -rf "$W/i"; mkdir -p "$W/i"; cd "$W/i"
+    "$NM" -D --defined-only "$R/xim-x-gcc/16.1.0/lib64/libstdc++.so.6" | awk '{print $3}' | sed 's/@.*//' | sort -u > gnu.txt
+    "$NM" --defined-only -g "$LL/lib/x86_64-unknown-linux-gnu/libc++.a" "$LL/lib/x86_64-unknown-linux-gnu/libc++abi.a" 2>/dev/null \
+        | awk 'NF==3 && $2 ~ /[TDRVWBui]/ {print $3}' | sort -u > llvm.txt
+    comm -12 gnu.txt llvm.txt > collide.txt; echo "collision set: $(wc -l < collide.txt)"
+    F="-fsycl -std=c++17 -O2 -fPIC --gcc-install-dir=$GID -isystem$GLIBC/include -isystem$UAPI/include"
+    nice -n 10 "$DX" $F -I"$P/include" -x c++ -c "$P/src/kernels/saxpy.sycl" -o saxpy.o
+    if [ -n "${TENSORVIA:-}" ]; then
+        for f in runtime arithmetic matmul; do
+            nice -n 10 "$DX" $F -I"$TENSORVIA/include" -I"$TENSORVIA/src/backend/sycl" -x c++ -c "$TENSORVIA/src/backend/sycl/device/$f.sycl" -o "tv_$f.o"
+        done
+    fi
+    for o in *.o; do
+        "$NM" -u "$o" | awk '{print $2}' | sort -u > u.txt
+        echo "== $o: $(comm -12 u.txt collide.txt | wc -l) in collision set; layout-sensitive:" \
+             "$(comm -12 u.txt collide.txt | c++filt | grep -c -E 'runtime_error|logic_error|out_of_range|invalid_argument|length_error|::what\(\)')"
+        echo "   foreign typeinfo: $(grep '^_ZTI' u.txt | comm -23 - collide.txt | c++filt | tr '\n' ' ')"
+    done
+fi

.agents/docs/README.md

@@ -18,7 +18,7 @@ superseded_by: 2026-09-07-....md  # when status is superseded
 ---
 ```
 
-336 records.
+337 records.
 
 ## By subject
 
@@ -64,6 +64,10 @@ Records that declare one. Everything else is listed by date below.
 - [A curriculum for the examples, a reference for the documentation, and a check with a denominator](2026-09-08-examples-curriculum-and-documentation-plan.md) — superseded by [2026-09-08-documentation-architecture-three-trees.md](2026-09-08-documentation-architecture-three-trees.md)
 - [Three documentation trees, three audiences, and the rule for citing between them](2026-09-08-documentation-architecture-three-trees.md) — active
 
+### ecosystem
+
+- [控制契约、并发与性能、单一 C++ 运行时，以及 IDE 生态（生态级，#838、#839）](2026-10-26-control-contract-runtime-and-ide-ecosystem-design.md) — active
+
 ### heterogeneous
 
 - [A dlopen surface no closure walks, and a process with two unwinders](2026-09-09-dlopen-surface-and-two-unwinders.md) — landed
@@ -139,6 +143,7 @@ Records that declare one. Everything else is listed by date below.
 
 ### 2026-10
 
+- [控制契约、并发与性能、单一 C++ 运行时，以及 IDE 生态（生态级，#838、#839）](2026-10-26-control-contract-runtime-and-ide-ecosystem-design.md) — active
 - [目标基座与执行宿主：sysroot 的通用模型、运行器契约、自备输入，以及同批的发布产物路径（#832）](2026-10-23-target-base-and-execution-host-design.md) — landed
 - [依赖 image 的资源归属、模块扫描边界与锁文件稳定写入](2026-10-21-resource-ownership-module-scan-and-lock-write-design.md) — active
 - [首次初始化、home 重定向与网络诊断优化设计](2026-10-19-first-run-home-and-network-design.md) — landed

.github/actions/bootstrap-mcpp/action.yml

@@ -33,7 +33,7 @@ inputs:
     # `package.name`, so one of the two was simply unreachable — and which one
     # depended on the machine, which is why CI failed on `compat:lua` on
     # Windows and `mcpplibs.capi:lua` on Linux. Never pin below that.
-    default: '2026.10.24.1'
+    default: '2026.10.26.1'
 
 outputs:
   sandbox-key:

.github/actions/setup-macos-llvm/action.yml

@@ -15,7 +15,7 @@ inputs:
     # Floor imposed by the index, not a routine bump — see
     # .github/actions/bootstrap-mcpp/action.yml for why 0.4.69 is required
     # (two packages named `lua` in one repo need openxlings/xlings#381).
-    default: '2026.10.24.1'
+    default: '2026.10.26.1'
   image:
     description: >
       The runner label the job runs on (macos-15, xcode-27). It is part of the

.github/tools/check_function_sizes.sh

@@ -29,7 +29,9 @@
 #
 # A compile database that names BMIs explicitly (-fmodule-file=...), which
 # only a build actually produces: `mcpp build --toolchain llvm@23.1.3` writes
-# compile_commands.json at the project root. This script does not build it:
+# the configuration's compile_commands.json, which target/.last-result.json
+# names (a root copy only when [build] compile_commands asks for one, mcpp
+# 2026.10.26.1+). This script does not build it:
 # the caller runs that build first. check_file_lengths.sh needs no such
 # division because it reads the tree.
 #
@@ -57,7 +59,18 @@ cd "$REPO_DIR" || { echo "FAIL: cannot cd to $REPO_DIR" >&2; exit 1; }
 LINE_THRESHOLD=400
 DIR="src/build/prepare"
 PRIMARY="src/build/prepare.cppm"
+# The database the build wrote: the project root's copy when the project asks
+# for one (`[build] compile_commands`), else the configuration's own, which the
+# result record names (mcpp 2026.10.26.1+, design 2026-10-26 D14).
 CDB="compile_commands.json"
+if [ ! -f "$CDB" ] && [ -f target/.last-result.json ]; then
+    CDB=$(python3 - <<'PY'
+import json
+last = json.load(open("target/.last-result.json"))["data"]["result"]
+print(json.load(open(last))["data"].get("compileDatabase") or "compile_commands.json")
+PY
+)
+fi
 
 [ -d "$DIR" ] || { echo "FAIL: $DIR does not exist -- this guard has gone stale" >&2; exit 1; }
 
@@ -68,8 +81,8 @@ FAIL: $CDB does not exist.
   compile database that names every imported module's BMI explicitly.
   Produce one first:
       mcpp build --toolchain llvm@23.1.3
-  (any installed LLVM row works; the database is written at the project
-  root regardless of the row's exact version).
+  (any installed LLVM row works; the database is read from the project
+  root, or from the configuration target/.last-result.json names).
 EOF
     exit 1
 fi
@@ -148,7 +161,7 @@ trap 'rm -f "$OUT"' EXIT
 "$CLANG_TIDY" \
     --checks='-*,readability-function-size' \
     --config="{CheckOptions: {readability-function-size.LineThreshold: '$LINE_THRESHOLD'}}" \
-    -p "$REPO_DIR" \
+    -p "$(dirname "$CDB")" \
     "${FILES[@]}" > "$OUT" 2>&1
 rc=$?
 

.github/tools/check_unicode_paths.sh

@@ -87,7 +87,10 @@ for name in ascii "$CAFE" "$CJK"; do
         if [ "$name" != ascii ]; then
             ninja=$(find target -name build.ninja -newer mcpp.toml | head -1)
             check_bytes "$ninja" "$name" "$label"
-            check_bytes compile_commands.json "$name" "$label"
+            # The configuration's database: the root copy is written only
+            # when [build] compile_commands asks for one (2026.10.26.1+).
+            cdb=$(find target -name compile_commands.json -newer mcpp.toml | head -1)
+            check_bytes "$cdb" "$name" "$label"
         fi
         ok "$label"
     done

.github/workflows/bootstrap-macos.yml

@@ -17,7 +17,7 @@ jobs:
       # Dormant (workflow_dispatch only), but kept in step with the rest —
       # check_version_pins.sh holds it there. Floor: 0.4.69, below which the
       # index cannot resolve two packages that share a short name.
-      XLINGS_VERSION: '2026.10.24.1'
+      XLINGS_VERSION: '2026.10.26.1'
     steps:
       - uses: actions/checkout@v4
 

.github/workflows/ci-bootstrap.yml

@@ -41,7 +41,7 @@ jobs:
         os: [ubuntu-24.04, macos-15, windows-2025]
     env:
       XLINGS_NON_INTERACTIVE: '1'
-      XLINGS_VERSION: '2026.10.24.1'
+      XLINGS_VERSION: '2026.10.26.1'
     steps:
       - uses: actions/checkout@v4
 
@@ -50,7 +50,7 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v2026.10.24.1
+          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v2026.10.26.1
           echo "$HOME/.xlings/subos/current/bin" >> "$GITHUB_PATH"
           echo "$HOME/.xlings/bin" >> "$GITHUB_PATH"
 
@@ -124,7 +124,7 @@ jobs:
         shell: bash
         run: |
           set -euo pipefail
-          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v2026.10.24.1
+          curl -fsSL https://raw.githubusercontent.com/openxlings/xlings/main/tools/other/quick_install.sh | bash -s v2026.10.26.1
           echo "$HOME/.xlings/subos/current/bin" >> "$GITHUB_PATH"
 
       - name: Install the newest release and build the tree with it (mcpp build --strict)