fix: add new fuzz targets

- template for adding targets

scripts/add_fuzz_target.py

@@ -0,0 +1,177 @@
+#!/usr/bin/env python3
+"""Fully automates registering a new cargo-fuzz target.
+
+Usage:
+    python3 scripts/add_fuzz_target.py <TARGET_NAME>
+
+Where TARGET_NAME is the full binary name, e.g. fuzz_my_feature.
+
+Actions performed:
+  1. Appends a [[bin]] entry to fuzz/Cargo.toml
+  2. Inserts TARGET_NAME into every YAML matrix block in
+     .github/workflows/fuzz.yml  (smoke-fuzz, regression)
+  3. Inserts TARGET_NAME into the perf-baseline shell for-loop in
+     .github/workflows/fuzz.yml
+
+Run from the repository root.
+"""
+
+import re
+import sys
+from pathlib import Path
+
+# Target names must follow the cargo-fuzz binary naming convention.
+_TARGET_RE = re.compile(r"^fuzz_[a-z][a-z0-9_]*$")
+
+
+def append_cargo_bin(target: str, cargo_toml: Path) -> None:
+    """Append a [[bin]] entry to fuzz/Cargo.toml if not already present."""
+    content = cargo_toml.read_text()
+    if f'name = "{target}"' in content:
+        print(f"  SKIP fuzz/Cargo.toml — [[bin]] {target!r} already present")
+        return
+
+    entry = (
+        f"\n[[bin]]\n"
+        f'name = "{target}"\n'
+        f'path = "fuzz_targets/{target}.rs"\n'
+        f"test = false\n"
+        f"bench = false\n"
+    )
+    cargo_toml.write_text(content.rstrip("\n") + "\n" + entry)
+    print(f"  [+] fuzz/Cargo.toml  — added [[bin]] {target!r}")
+
+
+def insert_into_yaml_matrices(target: str, content: str) -> tuple[str, int]:
+    """Insert target into YAML strategy matrix blocks.
+
+    Matches blocks of the form::
+
+        target:
+          - fuzz_a
+          - fuzz_b
+
+    and appends ``          - <target>`` after the last existing entry.
+    """
+    pattern = re.compile(
+        r"(        target:\n(?:          - fuzz_\w+\n)+)",
+        re.MULTILINE,
+    )
+
+    def add_target(m: re.Match) -> str:
+        return m.group(0) + f"          - {target}\n"
+
+    new_content, count = pattern.subn(add_target, content)
+    return new_content, count
+
+
+def insert_into_shell_loop(target: str, content: str) -> tuple[str, int]:
+    """Insert target into a 'for target in ... ; do' shell loop.
+
+    The last entry in the loop ends with ``; do``.  We change it to end with
+    a backslash continuation and append the new entry with ``; do``.
+
+    Example — before::
+
+              fuzz_block_verification; do
+
+    After::
+
+              fuzz_block_verification \\
+              fuzz_new_target; do
+    """
+    # Match the last fuzz target in the for-loop: "            fuzz_xxx; do"
+    # Indentation: 12 spaces (inside a run: | block).
+    pattern = re.compile(r"(            fuzz_\w+)(; do)", re.MULTILINE)
+
+    # We only want to replace the *last* occurrence (the closing entry).
+    matches = list(pattern.finditer(content))
+    if not matches:
+        return content, 0
+
+    if len(matches) > 1:
+        print(
+            f"  ERROR: found {len(matches)} shell loops matching the pattern; "
+            "cannot determine which one to update. "
+            "Please edit .github/workflows/fuzz.yml manually.",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    m = matches[-1]
+    replacement = f"{m.group(1)} \\\n            {target}{m.group(2)}"
+    new_content = content[: m.start()] + replacement + content[m.end() :]
+    return new_content, 1
+
+
+def insert_into_workflow(target: str, workflow: Path) -> None:
+    """Update all target lists in the fuzz workflow file."""
+    content = workflow.read_text()
+
+    if target in content:
+        print(f"  SKIP .github/workflows/fuzz.yml — {target!r} already present")
+        return
+
+    # 1. YAML matrix blocks (smoke-fuzz, regression)
+    content, yaml_count = insert_into_yaml_matrices(target, content)
+    if yaml_count:
+        print(
+            f"  [+] .github/workflows/fuzz.yml — inserted {target!r} into "
+            f"{yaml_count} YAML matrix block(s)"
+        )
+    else:
+        print(
+            f"  ERROR: no YAML matrix blocks matched in {workflow} — please edit manually",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    # 2. Shell for-loop (perf-baseline)
+    content, loop_count = insert_into_shell_loop(target, content)
+    if loop_count:
+        print(
+            f"  [+] .github/workflows/fuzz.yml — inserted {target!r} into "
+            f"perf-baseline shell loop"
+        )
+    else:
+        print(
+            f"  ERROR: perf-baseline shell loop not found in {workflow} — please edit manually",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    workflow.write_text(content)
+
+
+def main() -> None:
+    if len(sys.argv) != 2:
+        print(f"Usage: {sys.argv[0]} <TARGET_NAME>", file=sys.stderr)
+        sys.exit(1)
+
+    target = sys.argv[1]
+
+    if not _TARGET_RE.match(target):
+        print(
+            f"ERROR: target name must match fuzz_[a-z][a-z0-9_]*, got: {target!r}",
+            file=sys.stderr,
+        )
+        sys.exit(1)
+
+    root = Path(__file__).parent.parent  # repository root
+
+    cargo_toml = root / "fuzz" / "Cargo.toml"
+    workflow = root / ".github" / "workflows" / "fuzz.yml"
+
+    if not cargo_toml.exists():
+        print(f"ERROR: {cargo_toml} not found", file=sys.stderr)
+        sys.exit(1)
+    if not workflow.exists():
+        print(f"ERROR: {workflow} not found", file=sys.stderr)
+        sys.exit(1)
+
+    append_cargo_bin(target, cargo_toml)
+    insert_into_workflow(target, workflow)
+
+
+if __name__ == "__main__":
+    main()