Error in user YAML: (<unknown>): found character that cannot start any token while scanning for the next token at line 3 column 1

---

## Quick start — Python API

```python
import pyrift

# Scan a directory
result = pyrift.scan("./src")

print(result)
# ScanResult(files=23, errors=2, warnings=1, score=77)

# Iterate findings
for finding in result.findings:
    print(finding)

# Filter by severity
for error in result.errors:
    print(f"{error.file}:{error.line} — {error.title}")

# Export formats
json_output     = pyrift.to_json(result)
markdown_output = pyrift.to_markdown(result)
text_output     = pyrift.to_text(result)

# Scan a single file
findings = pyrift.scan_file("./src/utils.py")
```

---

Rules

CPython rules — version compatibility

ID	Title	Severity	Affects
CPY001	Dict ordering assumption	Warning	CPython < 3.7
CPY002	Exception.add_note() requires Python 3.11+	Error	CPython ≤ 3.10
CPY003	X | Y union type syntax requires Python 3.10+	Error	CPython ≤ 3.9
CPY004	tomllib requires Python 3.11+	Error	CPython ≤ 3.10
CPY005	match/case requires Python 3.10+	Error	CPython ≤ 3.9
CPY006	asyncio.timeout() / TaskGroup requires Python 3.11+	Error	CPython ≤ 3.10
CPY007	Module removed in Python 3.13 (21 modules)	Error	CPython ≥ 3.13
CPY008	__slots__ may not prevent __dict__ with base classes	Info	All versions
CPY009	ExceptionGroup requires Python 3.11+	Error	CPython ≤ 3.10
CPY010	@dataclass(slots=True) requires Python 3.10+	Error	CPython ≤ 3.9
CPY011	typing.Self requires Python 3.11+	Error	CPython ≤ 3.10
CPY012	typing.LiteralString requires Python 3.11+	Error	CPython ≤ 3.10
CPY013	typing.override requires Python 3.12+	Error	CPython ≤ 3.11
CPY014	typing.TypeAlias requires Python 3.10+	Error	CPython ≤ 3.9
CPY015	typing.Never requires Python 3.11+	Error	CPython ≤ 3.10
CPY016	typing.TypeVarTuple requires Python 3.11+	Error	CPython ≤ 3.10
CPY017	typing.Unpack requires Python 3.11+	Error	CPython ≤ 3.10
CPY018	typing.Required / NotRequired requires Python 3.11+	Error	CPython ≤ 3.10
CPY019	distutils removed in Python 3.12+	Error	CPython ≥ 3.12
CPY020	datetime.UTC requires Python 3.11+	Error	CPython ≤ 3.10
CPY021	asyncio.iscoroutinefunction() deprecated since 3.12	Warning	CPython ≥ 3.12
CPY022	Bitwise inversion on bool deprecated in 3.12	Warning	CPython ≥ 3.12
CPY023	multiprocessing default start method changing in 3.14	Warning	CPython ≥ 3.14
CPY024	typing.TypeGuard requires Python 3.10+	Error	CPython ≤ 3.9
CPY025	typing.ParamSpec requires Python 3.10+	Error	CPython ≤ 3.9
CPY026	typing.io and typing.re removed in Python 3.13	Error	CPython ≥ 3.13
CPY027	locale.resetlocale() removed in Python 3.13	Error	CPython ≥ 3.13
CPY028	lib2to3 removed in Python 3.13	Error	CPython ≥ 3.13
CPY029	locals() semantics changed in Python 3.13	Warning	CPython ≥ 3.13
CPY030	sys.path no longer accepts bytes in Python 3.11+	Error	CPython ≥ 3.11
CPY031	typing.assert_never requires Python 3.11+	Error	CPython ≤ 3.10
CPY032	typing.reveal_type requires Python 3.11+	Error	CPython ≤ 3.10
CPY033	pathlib.Path.is_relative_to() requires Python 3.9+	Error	CPython ≤ 3.8
CPY034	int.bit_count() requires Python 3.10+	Error	CPython ≤ 3.9
CPY035	str.removeprefix/removesuffix requires Python 3.9+	Error	CPython ≤ 3.8
CPY036	datetime.utcnow() deprecated since Python 3.12	Warning	CPython ≥ 3.12
CPY037	datetime.utcfromtimestamp() deprecated since Python 3.12	Warning	CPython ≥ 3.12
CPY038	asyncio.get_event_loop() raises RuntimeError in 3.12+	Error	CPython ≥ 3.12
CPY039	zoneinfo module requires Python 3.9+	Error	CPython ≤ 3.8
CPY040	graphlib module requires Python 3.9+	Error	CPython ≤ 3.8
CPY041	dict | merge operator requires Python 3.9+	Error	CPython ≤ 3.8
CPY042	aiter() and anext() builtins require Python 3.10+	Error	CPython ≤ 3.9
CPY043	math.lcm() requires Python 3.9+	Error	CPython ≤ 3.8
CPY044	math.gcd() multi-arg form requires Python 3.9+	Error	CPython ≤ 3.8
CPY045	NaN hash behaviour changed in Python 3.10	Warning	CPython ≥ 3.10

PyPy rules — runtime differences

ID	Title	Severity	Affects
PPY001	Relying on __del__ for resource cleanup	Error	PyPy all versions
PPY002	ctypes usage may silently fail	Warning	PyPy all versions
PPY003	sys.getrefcount() is meaningless on PyPy	Error	PyPy all versions
PPY004	weakref.proxy() raises ReferenceError unpredictably	Warning	PyPy all versions
PPY005	File write without explicit flush may lose data	Warning	PyPy all versions
PPY006	Monkey-patching built-in types behaves differently	Warning	PyPy all versions
PPY007	sys.intern() identity guarantees differ on PyPy	Warning	PyPy all versions
PPY008	threading.local() cleanup timing differs on PyPy	Warning	PyPy all versions
PPY009	id() values not stable across GC cycles on PyPy	Warning	PyPy all versions
PPY010	gc.collect() behaviour differs on PyPy	Warning	PyPy all versions
PPY011	array.array('u') type code removed in Python 3.13	Error	CPython ≥ 3.13
PPY012	Overriding built-in methods behaves differently on PyPy	Warning	PyPy all versions
PPY013	sys.getsizeof() raises TypeError on PyPy	Error	PyPy all versions
PPY014	String concatenation in loops is O(n²) on PyPy	Warning	PyPy all versions
PPY015	Generator cleanup timing differs on PyPy	Warning	PyPy all versions
PPY016	Instance __dict__ ordering not guaranteed on PyPy	Warning	PyPy all versions
PPY017	Adding __del__ to existing class not called on PyPy	Error	PyPy all versions
PPY018	sys.setrecursionlimit() behaviour differs on PyPy	Warning	PyPy all versions
PPY019	float('nan') identity differs between CPython and PyPy	Warning	PyPy all versions
PPY020	dict(**kwargs) requires string keys on PyPy	Error	PyPy all versions
PPY021	Socket not closed promptly on PyPy	Warning	PyPy all versions
PPY022	PYTHONHASHSEED=0 has no effect on PyPy	Warning	PyPy all versions
PPY023	inspect.ismethod() returns different results on PyPy	Warning	PyPy all versions
PPY024	timeit reports average not minimum on PyPy	Info	PyPy all versions
PPY025	Set iteration order differs between CPython and PyPy	Warning	PyPy all versions
PPY026	__builtins__ is always a module on PyPy	Warning	PyPy all versions
PPY027	Deleting module/class attributes is slower on PyPy	Warning	PyPy all versions
PPY028	readline.parse_and_bind() silently ignored on PyPy	Warning	PyPy all versions
PPY029	Assigning to __builtins__ has no effect on PyPy	Warning	PyPy all versions
PPY030	sys.flags values may differ between CPython and PyPy	Warning	PyPy all versions
PPY031	Integer is identity semantics differ on PyPy	Info	PyPy all versions
PPY032	Mutating dict keys raises RuntimeError on PyPy	Warning	PyPy all versions
PPY033	Exceptions in __del__ appear at unpredictable times	Warning	PyPy all versions
PPY034	hash() values may differ between CPython and PyPy	Info	PyPy all versions
PPY035	C extension packages may not work correctly on PyPy	Warning	PyPy all versions
PPY036	open() line buffering behaves differently on PyPy	Warning	PyPy all versions
PPY037	os.urandom() source may differ on PyPy	Info	PyPy all versions
PPY038	decimal module uses different backend on PyPy	Info	PyPy all versions
PPY039	os.fork() may not work correctly on all PyPy platforms	Warning	PyPy all versions
PPY040	subprocess.PIPE buffering may cause deadlocks on PyPy	Warning	PyPy all versions
PPY041	dict | operator requires PyPy 7.3.7+	Info	PyPy < 7.3.7
PPY042	print(flush=True) may not flush immediately on PyPy	Info	PyPy all versions
PPY043	__slots__ memory savings differ on PyPy	Info	PyPy all versions
PPY044	Exception variable cleanup timing differs on PyPy	Info	PyPy all versions
PPY045	sys.settrace() disables JIT on PyPy	Warning	PyPy all versions

Full rule documentation: docs/rules.md

---

Use in CI

Add pyrift to your GitHub Actions workflow:

- name: Run pyrift
  run: |
    pip install pyrift
    pyrift scan . --format json --output pyrift-report.json
    pyrift scan .

Exit code is 1 when errors are found — fails the CI build automatically. Use --exit-zero to report without failing.

---

Use with pre-commit

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/BHUVANSH855/pyrift
    rev: v0.8.0
    hooks:
      - id: pyrift

---

Why pyrift?

Tool	What it catches	What it misses
pylint / ruff	Style, common bugs	Runtime behaviour differences
mypy / pyright	Type errors	Runtime behaviour differences
pip-audit	Known CVEs	Behaviour differences
bandit	Security patterns	Behaviour differences
pyrift	Silent runtime behaviour differences	(that's the whole point)

pyrift does not replace any of these tools. It catches what they all miss.

---

Roadmap

Planned for upcoming versions — contributions welcome:

• CPY064+ — next CPython compatibility rules (open for contributions)
• PPY048+ — next PyPy runtime difference rules (open for contributions)
• Pre-commit hook native support
• VS Code extension
• GitHub Action marketplace listing

See CONTRIBUTING.md to add a rule yourself — rule IDs CPY046+ and PPY046+ are open for community contributions.

---

Contributing

Contributions are very welcome — especially new rules for behaviour differences you have personally encountered.

See CONTRIBUTING.md for the full guide.

---

Project status

• Version: 0.8.0
• Rules: 104 total (58 CPython + 44 PyPy + 2 cross-runtime)
• Tests: 608 passing
• Dependencies: zero
• Python: 3.10+

---

Author

Built by Bhuvansh Kataria — CPython contributor and PyPy toolkit author.

---

License

MIT — see LICENSE