chore: add preview changelog script

Author: piotr-iohk

scripts/preview-changelog.sh

@@ -0,0 +1,133 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  cat <<'EOF'
+Usage: scripts/preview-changelog.sh [--target next|hotfix|all]
+
+Preview pending changelog fragments without modifying files.
+EOF
+}
+
+target="all"
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --target)
+      if [[ $# -lt 2 ]]; then
+        echo "--target requires a value" >&2
+        usage >&2
+        exit 1
+      fi
+      target="$2"
+      shift 2
+      ;;
+    -h|--help)
+      usage
+      exit 0
+      ;;
+    *)
+      echo "Unknown argument: $1" >&2
+      usage >&2
+      exit 1
+      ;;
+  esac
+done
+
+if [[ "$target" != "next" && "$target" != "hotfix" && "$target" != "all" ]]; then
+  echo "--target must be 'next', 'hotfix', or 'all'" >&2
+  usage >&2
+  exit 1
+fi
+
+python3 - "$target" <<'PY'
+from __future__ import annotations
+
+import re
+import sys
+from pathlib import Path
+
+TARGET = sys.argv[1]
+ROOT = Path.cwd()
+CHANGELOG_DIR = ROOT / "changelog.d"
+
+CATEGORY_LABELS = {
+    "added": "Added",
+    "changed": "Changed",
+    "deprecated": "Deprecated",
+    "removed": "Removed",
+    "fixed": "Fixed",
+    "security": "Security",
+}
+CATEGORY_ORDER = list(CATEGORY_LABELS.values())
+FRAGMENT_PATTERN = re.compile(
+    r"^(?P<ref>[A-Za-z0-9][A-Za-z0-9._-]*)\.(?P<category>added|changed|deprecated|removed|fixed|security)\.md$"
+)
+
+
+def fail(message: str) -> None:
+    raise SystemExit(f"preview-changelog: {message}")
+
+
+def fragment_entry(path: Path) -> tuple[str, str]:
+    match = FRAGMENT_PATTERN.match(path.name)
+    if not match:
+        fail(
+            f"invalid fragment name '{path.relative_to(ROOT)}'; "
+            "expected <issue-or-pr>.<category>.md"
+        )
+
+    lines = [line.strip() for line in path.read_text().splitlines() if line.strip()]
+    if not lines:
+        fail(f"fragment '{path.relative_to(ROOT)}' is empty")
+
+    text = " ".join(lines)
+    if text.startswith("-"):
+        fail(f"fragment '{path.relative_to(ROOT)}' must not start with a bullet")
+
+    ref = match.group("ref")
+    category = CATEGORY_LABELS[match.group("category")]
+    suffix = f" #{ref}" if ref.isdigit() else ""
+    return category, f"- {text}{suffix} ({path.relative_to(ROOT)})"
+
+
+def target_dirs() -> list[tuple[str, Path]]:
+    targets = ["next", "hotfix"] if TARGET == "all" else [TARGET]
+    return [(target, CHANGELOG_DIR / target) for target in targets]
+
+
+found_any = False
+
+for target, directory in target_dirs():
+    if not directory.exists():
+        fail(f"fragment directory '{directory.relative_to(ROOT)}' does not exist")
+
+    fragments = sorted(
+        path for path in directory.glob("*.md") if path.is_file() and path.name != ".gitkeep"
+    )
+
+    print(f"## {target}")
+    if not fragments:
+        print("No pending changelog fragments.\n")
+        continue
+
+    found_any = True
+    entries_by_category: dict[str, list[str]] = {category: [] for category in CATEGORY_ORDER}
+    for fragment in fragments:
+        category, entry = fragment_entry(fragment)
+        entries_by_category[category].append(entry)
+
+    for category in CATEGORY_ORDER:
+        entries = entries_by_category[category]
+        if not entries:
+            continue
+
+        print(f"\n### {category}")
+        for entry in entries:
+            print(entry)
+
+    print()
+
+if not found_any:
+    raise SystemExit(0)
+PY