docs(ci): scope build-doc command checks to changed files

.github/workflows/docs-build-command-check.yml

@@ -0,0 +1,36 @@
+---
+name: docs-build-command-check
+
+on:
+  pull_request:
+  push:
+    branches: [master]
+
+jobs:
+  docs-build-command-check:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.x'
+
+      - name: Collect changed files
+        id: changed
+        run: |
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            git diff --name-only origin/${{ github.base_ref }}...HEAD > changed_files.txt
+          else
+            git diff --name-only HEAD~1..HEAD > changed_files.txt || true
+          fi
+          tr '\n' ' ' < changed_files.txt > changed_files_space.txt
+          echo "files=$(cat changed_files_space.txt)" >> "$GITHUB_OUTPUT"
+
+      - name: Run build-docs command checks (changed files only)
+        run: |
+          python3 tools/check_build_docs_commands.py --files ${{ steps.changed.outputs.files }}

tools/check_build_docs_commands.py

@@ -0,0 +1,102 @@
+#!/usr/bin/env python3
+from __future__ import annotations
+import argparse
+import re
+from pathlib import Path
+import subprocess
+import tempfile
+
+ROOT = Path(__file__).resolve().parents[1]
+DEFAULT_DOCS = sorted((ROOT / "docs" / "variants").glob("**/building-manual.md"))
+BLOCK_RE = re.compile(r"```(?:bash|sh|shell)?\n(.*?)```", re.S)
+ALLOWED_PREFIXES = (
+    "git ", "make", "cmake", "docker", "podman", "python", "python3", "pip", "pip3",
+    "./", "sudo ", "export ", "cd ", "echo ", "cat ", "ls", "mkdir", "rm ", "cp ", "mv ",
+    "source ", "ninja", "west", "repo ", "curl ", "wget ", "tar ", "xz ", "unzip ",
+)
+
+def extract_blocks(text: str):
+    for m in BLOCK_RE.finditer(text):
+        b = m.group(1).strip()
+        if b:
+            yield b
+
+def should_skip_block(block: str) -> bool:
+    b = block.lower()
+    markers = ["<version>", "<variant>", "(docker)", "<path>"]
+    return any(m in b for m in markers)
+
+def check_bash_syntax(block: str):
+    with tempfile.NamedTemporaryFile("w", suffix=".sh", delete=True) as f:
+        f.write(block + "\n")
+        f.flush()
+        p = subprocess.run(["bash", "-n", f.name], capture_output=True, text=True)
+        return p.returncode == 0, (p.stderr or p.stdout).strip()
+
+def is_cmd(line: str):
+    s = line.strip()
+    if not s or s.startswith("#"):
+        return False
+    if s in ("fi", "done", "then", "do", "esac", "else"):
+        return False
+    return True
+
+def pick_docs(files: list[str]) -> list[Path]:
+    if not files:
+        return DEFAULT_DOCS
+    out = []
+    for f in files:
+        p = (ROOT / f).resolve() if not f.startswith('/') else Path(f)
+        if p.exists() and p.name == 'building-manual.md' and str(p).startswith(str(ROOT)):
+            out.append(p)
+    return sorted(set(out))
+
+def main() -> int:
+    ap = argparse.ArgumentParser()
+    ap.add_argument('--files', nargs='*', default=[])
+    args = ap.parse_args()
+
+    docs = pick_docs(args.files)
+    failures = []
+    warns = []
+    tested = 0
+
+    if not docs:
+        print("[docs-check] no target build-manual.md files selected")
+        return 0
+
+    for doc in docs:
+        text = doc.read_text(encoding="utf-8", errors="ignore")
+        for i, block in enumerate(extract_blocks(text), 1):
+            tested += 1
+            if should_skip_block(block):
+                warns.append((str(doc), i, "placeholder/pseudocode block skipped"))
+                continue
+            ok, err = check_bash_syntax(block)
+            if not ok:
+                failures.append((str(doc), i, err))
+            for ln, line in enumerate(block.splitlines(), 1):
+                s = line.strip()
+                if not is_cmd(s):
+                    continue
+                if s.startswith(("if ", "for ", "while ", "case ")):
+                    continue
+                if not s.startswith(ALLOWED_PREFIXES):
+                    warns.append((str(doc), i, f"line {ln}: uncommon prefix -> {s}"))
+
+    print(f"[docs-check] scanned files: {len(docs)}")
+    print(f"[docs-check] tested blocks: {tested}")
+    if warns:
+        print("[docs-check] warnings:")
+        for d, i, w in warns:
+            print(f"  - {d} block#{i}: {w}")
+    if failures:
+        print("[docs-check] failures:")
+        for d, i, e in failures:
+            print(f"  - {d} block#{i}: {e}")
+        return 1
+    print("[docs-check] OK")
+    return 0
+
+if __name__ == '__main__':
+    raise SystemExit(main())