ci: onboard Blacksmith Testbox

.github/actionlint.yaml

@@ -19,4 +19,5 @@ self-hosted-runner:
     # Linux: Blacksmith primary (LINUX_RUNNER), WarpBuild overflow fallback.
     - blacksmith-4vcpu-ubuntu-2404
     - blacksmith-8vcpu-ubuntu-2404
+    - blacksmith-32vcpu-ubuntu-2404
     - warp-ubuntu-latest-x64-4x

.github/workflows/ci-workflow-guard-tests-testbox.yml

@@ -0,0 +1,114 @@
+name: cmux-tui Rust Testbox setup
+
+on:
+  workflow_dispatch:
+    inputs:
+      testbox_id:
+        description: "Testbox session ID supplied by blacksmith testbox warmup"
+        required: true
+        type: string
+
+permissions:
+  contents: read
+
+jobs:
+  cmux-tui-rust:
+    name: cmux-tui Rust setup
+    runs-on: blacksmith-32vcpu-ubuntu-2404
+    timeout-minutes: 45
+    steps:
+      # begin-testbox must be the first step. It attaches the VM requested by
+      # `blacksmith testbox warmup` and leaves it alive after this setup job.
+      - name: Begin Testbox
+        uses: useblacksmith/begin-testbox@233448af4bfdc6fca509a7f0974411ac6d8a8043 # v2
+        with:
+          testbox_id: ${{ inputs.testbox_id }}
+
+      - name: Checkout exact dispatch commit
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          fetch-depth: 0
+          persist-credentials: false
+          ref: ${{ github.sha }}
+
+      - name: Require exact checkout
+        env:
+          EXPECTED_SHA: ${{ github.sha }}
+        shell: bash
+        run: |
+          actual_sha="$(git rev-parse HEAD)"
+          if [[ "$actual_sha" != "$EXPECTED_SHA" ]]; then
+            echo "::error::checked out $actual_sha, expected dispatch SHA $EXPECTED_SHA" >&2
+            exit 1
+          fi
+          printf 'testbox setup commit: %s\n' "$actual_sha"
+
+      - name: Initialize Ghostty source submodule
+        shell: bash
+        run: |
+          git submodule update --init --depth 1 ghostty
+          test -f ghostty/build.zig.zon
+
+      - name: Install Linux build dependencies
+        shell: bash
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y clang libclang-dev pkg-config
+
+      - name: Cache Zig package downloads
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        with:
+          path: ~/.cache/zig
+          key: cmux-tui-zig-${{ hashFiles('ghostty/build.zig.zon', 'ghostty/build.zig.zon.json') }}
+          restore-keys: |
+            cmux-tui-zig-
+
+      - name: Install repository-pinned Zig
+        shell: bash
+        run: ./scripts/install-zig-ci.sh
+
+      - name: Fetch Ghostty Zig dependencies without compiling
+        working-directory: ghostty
+        shell: bash
+        run: |
+          # `--fetch` hydrates the package cache and exits before a build.
+          "$CMUX_ZIG" build --fetch
+
+      - name: Cache Cargo registry and git dependencies
+        uses: actions/cache@27d5ce7f107fe9357f9df03efb73ab90386fccae # v5.0.5
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+          key: cmux-tui-cargo-${{ runner.os }}-${{ hashFiles('cmux-tui/Cargo.lock', 'cmux-tui/rust-toolchain.toml') }}
+          restore-keys: |
+            cmux-tui-cargo-${{ runner.os }}-
+
+      - name: Set up repository-pinned cmux-tui Rust
+        uses: ./.github/actions/setup-cmux-tui-rust
+
+      - name: Fetch Cargo dependencies without compiling
+        working-directory: cmux-tui
+        shell: bash
+        run: cargo fetch --locked
+
+      - name: Record hydrated toolchain and workspace metadata
+        working-directory: cmux-tui
+        shell: bash
+        run: |
+          printf 'rust-toolchain: '
+          rustup show active-toolchain
+          printf 'cargo: '
+          cargo --version
+          printf 'rustc: '
+          rustc --version
+          printf 'zig: '
+          "$CMUX_ZIG" version
+          cargo metadata --locked --no-deps --format-version 1 > "$RUNNER_TEMP/cmux-tui-cargo-metadata.json"
+          test -s "$RUNNER_TEMP/cmux-tui-cargo-metadata.json"
+
+      # Always hand control back to Testbox. Warmup is setup-only: all actual
+      # Rust builds are issued later with `blacksmith testbox run`.
+      - name: Run Testbox
+        uses: useblacksmith/run-testbox@5ca05834db1d3813554d1dd109e5f2087a8d7cbc # v2
+        if: always()

.gitignore

@@ -73,3 +73,7 @@ artifacts/
 
 # tmux verbose debug logs (tmux -v) that land in the cwd
 tmux-*.log
+
+# Remote-only Blacksmith cmux-tui benchmark output
+testbox-benchmark/
+.cmux-scratch/

scripts/blacksmith-cmux-tui-testbox-stage.sh

@@ -0,0 +1,129 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# This helper is intentionally remote-only. The local benchmark plan invokes it
+# through `blacksmith testbox run`; the guard makes an accidental local launch a
+# no-op instead of running a Rust build on the developer's Mac.
+if [[ "${CMUX_TESTBOX_REMOTE:-}" != "1" ]]; then
+  echo "refusing to run outside a Blacksmith Testbox (set CMUX_TESTBOX_REMOTE=1 only in the remote command)" >&2
+  exit 64
+fi
+
+if [[ $# -ne 1 ]]; then
+  echo "usage: CMUX_TESTBOX_REMOTE=1 $0 {first-clean|incremental-noop|changed-file}" >&2
+  exit 64
+fi
+
+stage="$1"
+case "$stage" in
+  first-clean|incremental-noop|changed-file) ;;
+  *)
+    echo "unsupported benchmark stage: $stage" >&2
+    exit 64
+    ;;
+esac
+
+repo_root="$(git rev-parse --show-toplevel)"
+cd "$repo_root"
+if [[ ! -f cmux-tui/Cargo.toml || ! -f ghostty/.git || ! -f ghostty/build.zig.zon ]]; then
+  echo "cmux-tui and its Ghostty source submodule must be initialized" >&2
+  exit 65
+fi
+
+benchmark_dir="$repo_root/testbox-benchmark"
+mkdir -p "$benchmark_dir"
+# Testbox can acknowledge a run while its remote shell is still flushing
+# output. Serialize stages and hold the lock through artifact writes so a
+# subsequent run cannot overwrite a prior stage's timing file.
+exec 9>"$benchmark_dir/.stage.lock"
+flock -x 9
+log_path="$benchmark_dir/$stage.log"
+time_path="$benchmark_dir/$stage.time"
+json_path="$benchmark_dir/$stage.json"
+changed_file="cmux-tui/crates/cmux-tui/src/main.rs"
+changed_backup=""
+
+# shellcheck disable=SC2329 # invoked indirectly by the EXIT trap
+restore_changed_file() {
+  if [[ -n "$changed_backup" && -f "$changed_backup" ]]; then
+    cp "$changed_backup" "$repo_root/$changed_file"
+    rm -f "$changed_backup"
+  fi
+}
+trap restore_changed_file EXIT
+
+case "$stage" in
+  first-clean)
+    rm -rf "$repo_root/cmux-tui/target"
+    ;;
+  changed-file)
+    changed_backup="$(mktemp "${TMPDIR:-/tmp}/cmux-tui-testbox-source.XXXXXX")"
+    cp "$repo_root/$changed_file" "$changed_backup"
+    printf '\n// Blacksmith Testbox changed-file timing marker.\n' >> "$repo_root/$changed_file"
+    ;;
+esac
+
+start_epoch="$(python3 -c 'import time; print(time.time())')"
+set +e
+(
+  cd "$repo_root/cmux-tui"
+  /usr/bin/time -p -o "$time_path" cargo build -p cmux-tui --locked
+) >"$log_path" 2>&1
+status=$?
+set -e
+end_epoch="$(python3 -c 'import time; print(time.time())')"
+
+python3 - "$stage" "$start_epoch" "$end_epoch" "$status" "$time_path" "$changed_file" >"$json_path" <<'PY'
+import datetime as dt
+import json
+import os
+import platform
+import subprocess
+import sys
+
+stage, start, end, status, time_path, changed_file = sys.argv[1:]
+start = float(start)
+end = float(end)
+status = int(status)
+remote_time = {}
+with open(time_path, encoding="utf-8") as handle:
+    for line in handle:
+        key, _, value = line.strip().partition(" ")
+        if key in {"real", "user", "sys"}:
+            remote_time[f"time_{key}_seconds"] = float(value)
+
+try:
+    git_sha = subprocess.check_output(
+        ["git", "rev-parse", "HEAD"], text=True, stderr=subprocess.DEVNULL
+    ).strip()
+except subprocess.CalledProcessError:
+    git_sha = "unknown"
+
+record = {
+    "schema": 1,
+    "stage": stage,
+    "command": "cargo build -p cmux-tui --locked",
+    "exit_code": status,
+    "ok": status == 0,
+    "started_at": dt.datetime.fromtimestamp(start, dt.timezone.utc).isoformat(),
+    "finished_at": dt.datetime.fromtimestamp(end, dt.timezone.utc).isoformat(),
+    "wall_seconds": round(end - start, 3),
+    "git_sha": git_sha,
+    "runner": {
+        "hostname": platform.node(),
+        "arch": platform.machine(),
+        "cpu_count": os.cpu_count(),
+        "uname": " ".join(platform.uname()),
+    },
+    "changed_file": changed_file if stage == "changed-file" else None,
+    **remote_time,
+}
+print(json.dumps(record, sort_keys=True))
+PY
+
+cat "$log_path"
+printf '\n--- /usr/bin/time -p (%s) ---\n' "$stage"
+cat "$time_path"
+printf '\n--- structured timing (%s) ---\n' "$stage"
+cat "$json_path"
+exit "$status"