ci: reject implicit engine buffer allocation

Signed-off-by: Nicholas Gates <nick@nickgates.com>

Author: gatesn

.github/workflows/ci.yml

@@ -349,6 +349,10 @@ jobs:
         id: fmt
         continue-on-error: true
         run: cargo +$NIGHTLY_TOOLCHAIN fmt --all --check
+      - name: Buffer allocator check
+        id: buffer-allocators
+        continue-on-error: true
+        run: python3 scripts/check-buffer-allocators.py
       - name: Rustc check
         id: check
         continue-on-error: true
@@ -372,6 +376,7 @@ jobs:
           script: |
             const failed = Object.entries({
               fmt: '${{ steps.fmt.outcome }}',
+              'buffer-allocators': '${{ steps.buffer-allocators.outcome }}',
               check: '${{ steps.check.outcome }}',
               'check-release': '${{ steps.check-release.outcome }}',
               'clippy-all': '${{ steps.clippy-all.outcome }}',

scripts/check-buffer-allocators.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python3
+
+import re
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parent.parent
+PATHS = (
+    "vortex-array/src/arrays/filter/execute",
+    "vortex-array/src/arrays/fixed_width/filter.rs",
+    "vortex-array/src/arrays/fixed_width/take",
+    "vortex-array/src/arrays/interleave/execute",
+    "vortex-array/src/patches.rs",
+    "vortex-array/src/scalar_fn/fns",
+)
+TYPES = r"(?:ByteBuffer|Buffer|BitBuffer|ByteBufferMut|BufferMut|BitBufferMut)"
+METHODS = "|".join(
+    (
+        "with_capacity",
+        "with_capacity_aligned",
+        "with_capacity_preferred_aligned",
+        "zeroed",
+        "zeroed_aligned",
+        "empty",
+        "empty_aligned",
+        "copy_from",
+        "copy_from_aligned",
+        "full",
+        "new_set",
+        "new_unset",
+        "collect_bool",
+        "collect_bool_multiversioned",
+        "from_trusted_len_iter",
+        "try_from_trusted_len_iter",
+    )
+)
+STATIC_ALLOCATION = re.compile(rf"\b{TYPES}::(?:{METHODS})\s*\(")
+
+
+def rust_files(path: Path):
+    files = path.rglob("*.rs") if path.is_dir() else (path,)
+    return (
+        file
+        for file in files
+        if file.name != "tests.rs" and "tests" not in file.relative_to(ROOT).parts
+    )
+
+
+failures = []
+for relative in PATHS:
+    for file in rust_files(ROOT / relative):
+        for number, line in enumerate(file.read_text().splitlines(), 1):
+            if STATIC_ALLOCATION.search(line):
+                failures.append(f"{file.relative_to(ROOT)}:{number}: {line.strip()}")
+
+if failures:
+    print("Engine buffers must use an allocator-aware constructor ending in `_in`.")
+    print("\n".join(failures))
+    raise SystemExit(1)