0.0.1-alpha.3

scripts/audit_rust_item_spacing.py

@@ -0,0 +1,168 @@
+#!/usr/bin/env python3
+# file: scripts/audit_rust_item_spacing.py
+# version: 1
+
+"""Audit exact spacing between mechanically detectable Rust items."""
+
+from __future__ import annotations
+
+import argparse
+import dataclasses
+import pathlib
+import re
+import sys
+
+from _rust_audit_common import line_depths, mask_source, selected_files
+
+
+@dataclasses.dataclass(frozen=True)
+class RustItem:
+    """One mechanically detected Rust item and its source span."""
+
+    kind: str
+    visibility: str
+    start: int
+    declaration: int
+    end: int
+    depth: int
+    braced: bool
+
+
+def _visibility(stripped: str) -> str:
+    if stripped.startswith("pub(crate) "):
+        return "pub(crate)"
+    if stripped.startswith("pub "):
+        return "pub"
+    return "private"
+
+
+def _kind(stripped: str) -> str | None:
+    prefix = r"(?:(?:pub|pub\(crate\))\s+)?"
+    qualifiers = r"(?:(?:async|const|unsafe)\s+)*"
+    if re.match(rf"^{prefix}{qualifiers}fn\b", stripped):
+        return "fn"
+    for kind in ("struct", "enum", "union", "trait", "impl", "const", "static", "type"):
+        if re.match(rf"^{prefix}{qualifiers}{kind}\b", stripped):
+            return kind
+    return None
+
+
+def _leading_line(lines: list[str], declaration: int) -> int:
+    cursor = declaration - 2
+    while cursor >= 0:
+        stripped = lines[cursor].strip()
+        if stripped.startswith("///") or stripped.startswith("#["):
+            cursor -= 1
+            continue
+        break
+    return cursor + 2
+
+
+def _end_line(masked_lines: list[str], depths: list[int], declaration: int, kind: str) -> tuple[int, bool]:
+    start_depth = depths[declaration - 1]
+    if kind in {"const", "static", "type"}:
+        brackets: list[str] = []
+        closing = {"}": "{", ")": "(", "]": "["}
+        for line_index in range(declaration - 1, len(masked_lines)):
+            for char in masked_lines[line_index]:
+                if char in "{([":
+                    brackets.append(char)
+                elif char in "})]" and brackets and brackets[-1] == closing[char]:
+                    brackets.pop()
+                elif char == ";" and not brackets:
+                    return line_index + 1, False
+        return declaration, False
+    body_started = False
+    for line_index in range(declaration - 1, len(masked_lines)):
+        masked_line = masked_lines[line_index]
+        if not body_started and ";" in masked_line and "{" not in masked_line:
+            return line_index + 1, False
+        if "{" in masked_line:
+            body_started = True
+        if body_started:
+            end_depth = depths[line_index] + masked_line.count("{") - masked_line.count("}")
+            if end_depth == start_depth:
+                return line_index + 1, True
+    return declaration, body_started
+
+
+def _items(lines: list[str], masked_lines: list[str], depths: list[int]) -> list[RustItem]:
+    result: list[RustItem] = []
+    for number, line in enumerate(lines, 1):
+        stripped = line.strip()
+        kind = _kind(stripped)
+        if kind is None:
+            continue
+        end, braced = _end_line(masked_lines, depths, number, kind)
+        result.append(RustItem(kind, _visibility(stripped), _leading_line(lines, number), number, end, depths[number - 1], braced))
+    return result
+
+
+def _parent(item: RustItem, items: list[RustItem]) -> RustItem | None:
+    parents = [candidate for candidate in items if candidate.braced and candidate.declaration < item.declaration <= candidate.end and candidate.depth < item.depth]
+    if not parents:
+        return None
+    return max(parents, key=lambda candidate: candidate.depth)
+
+
+def audit_file(path: pathlib.Path) -> list[str]:
+    """Require exact separation between adjacent items in one Rust scope."""
+
+    text = path.read_text(encoding="utf-8")
+    lines = text.splitlines()
+    masked, _ = mask_source(text)
+    masked_lines = masked.splitlines()
+    depths = line_depths(masked)
+    items = _items(lines, masked_lines, depths)
+    siblings: dict[tuple[int, int] | None, list[RustItem]] = {}
+    for item in items:
+        parent = _parent(item, items)
+        key = None if parent is None else (parent.declaration, parent.end)
+        siblings.setdefault(key, []).append(item)
+
+    errors: list[str] = []
+    for group in siblings.values():
+        group.sort(key=lambda item: item.declaration)
+        for previous, current in zip(group, group[1:]):
+            between = lines[previous.end:current.start - 1]
+            # Unknown syntax or a macro between items owns its own layout; do not infer across it.
+            if any(candidate.strip() for candidate in between):
+                continue
+            blank_count = sum(1 for candidate in between if not candidate.strip())
+            compact = previous.kind == current.kind and previous.kind in {"const", "static", "type"} and previous.visibility == current.visibility
+            if compact:
+                # Compact declaration blocks have a dedicated owner when a project selects one.
+                continue
+            if blank_count != 1:
+                errors.append(f"{path}:{current.start}: expected exactly one blank line between Rust items; found {blank_count}")
+    return errors
+
+
+def main() -> int:
+    """Run the read-only item-spacing audit on explicitly selected Rust files."""
+
+    parser = argparse.ArgumentParser(description=__doc__)
+    parser.add_argument("paths", nargs="+", help="Rust files or directories to inspect")
+    args = parser.parse_args()
+    files, errors = selected_files(args.paths)
+    if errors or not files:
+        for error in errors or ["no Rust files selected"]:
+            print(f"Rust item-spacing audit: {error}", file=sys.stderr)
+        return 2
+    for path in files:
+        try:
+            errors.extend(audit_file(path))
+        except (OSError, UnicodeError) as error:
+            print(f"Rust item-spacing audit: cannot read {path}: {error}", file=sys.stderr)
+            return 2
+    for error in errors:
+        print(error, file=sys.stderr)
+    if errors:
+        print(f"Rust item-spacing audit: {len(errors)} error(s) across {len(files)} file(s)", file=sys.stderr)
+        return 1
+    print(f"Rust item-spacing audit: clean ({len(files)} file(s))")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())