wait-for2
Asyncio wait_for that can handle simultaneous cancellation and future completion.
Decision gist · record as of 2026-08-14
Yes, if you support Python 3.7–3.11 and need bulletproof timeout and cancellation semantics in asyncio code. The package is low-friction to install and has no dependencies. On Python 3.12+, it transparently uses the builtin implementation, so it is safe to leave in place during version upgrades. If you only target Python 3.12+, the builtin asyncio.wait_for is sufficient and this package is unnecessary.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.7 or later; on Python 3.12+ the package delegates to the builtin asyncio.wait_for unless a race_handler is explicitly provided.
- Low install friction; pure Python wheel with no runtime dependencies.
- Maintenance status is aging (last release June 2025, 427 days old), but the repository remains active and the package is explicitly designed to become unnecessary on Python 3.12+, where the builtin asyncio.wait_for was fixed.
License · maintenance · safety
Apache-2.0 (permissive) — Licensed under Apache-2.0 (permissive), imposing no significant restrictions on use or redistribution in most contexts.
last release 2025-06-13 (427 days) · last repo commit 2025-06-13 · 3 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 330,746 downloads/mo, #7,531 on PyPI
Alternatives
Verify before relying
import asyncio
import wait_for2
task = asyncio.create_task(...)
try:
result = await wait_for2.wait_for(task, 5.0)
except wait_for2.CancelledWithResultError as e:
# Handle simultaneous cancellation and result
result = e.result
raise asyncio.CancelledError()- Whether the package's race-condition handling callbacks (race_handler parameter) are thread-safe or have any async-context limitations.
- Performance overhead of wait_for2 compared to builtin asyncio.wait_for on Python 3.10–3.11.
What it is and what it does
wait_for2 is a drop-in replacement for asyncio.wait_for() that addresses a family of race conditions present in Python's builtin implementation across versions 3.7–3.11. When a timeout fires and the inner future completes simultaneously, or when cancellation and completion occur at the same time, the builtin asyncio.wait_for() can either lose the future's result or ignore the cancellation request, depending on the Python version. wait_for2 instead raises a CancelledWithResultError that contains both the cancellation signal and the result, allowing caller code to decide how to handle the edge case. Alternatively, a callback-based race_handler can be provided to process the result without raising an exception.
The package is explicitly designed as a compatibility shim: on Python 3.12+, where the builtin asyncio.wait_for was fixed, wait_for2 delegates to the standard library unless a race_handler is explicitly passed. For Python 3.7–3.11, it provides consistent, predictable behavior across all versions and implementations (CPython and PyPy). It has no runtime dependencies and installs as a pure Python wheel.
Use it for
- Ensuring timeout and cancellation safety in asyncio code that must support Python 3.7–3.11 without losing results or cancellation signals.
- Handling edge cases where a task completes and is cancelled in the same event-loop cycle, using either exception handling or a callback.
- Migrating legacy asyncio code from Python 3.7–3.10 to newer versions while maintaining consistent race-condition semantics.
- Building robust async libraries that need predictable timeout behavior across multiple Python versions and implementations.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you support Python 3.7–3.11 and need bulletproof timeout and cancellation semantics in asyncio code.
The package is low-friction to install and has no dependencies. On Python 3.12+, it transparently uses the builtin implementation, so it is safe to leave in place during version upgrades. If you only target Python 3.12+, the builtin asyncio.wait_for is sufficient and this package is unnecessary.
Install
wait-for2 on PyPI
Before you install
Low install friction; pure Python wheel with no runtime dependencies. Maintenance status is aging (last release June 2025, 427 days old), but the repository remains active and the package is explicitly designed to become unnecessary on Python 3.12+, where the builtin asyncio.wait_for was fixed.
Requires Python 3.7 or later; on Python 3.12+ the package delegates to the builtin asyncio.wait_for unless a race_handler is explicitly provided.
License in practice
Licensed under Apache-2.0 (permissive), imposing no significant restrictions on use or redistribution in most contexts.
Quickstart
import asyncio
import wait_for2
task = asyncio.create_task(...)
try:
result = await wait_for2.wait_for(task, 5.0)
except wait_for2.CancelledWithResultError as e:
# Handle simultaneous cancellation and result
result = e.result
raise asyncio.CancelledError()Verify before relying
- Whether the package's race-condition handling callbacks (race_handler parameter) are thread-safe or have any async-context limitations.
- Performance overhead of wait_for2 compared to builtin asyncio.wait_for on Python 3.10–3.11.
Package facts
| License | Apache-2.0 permissive |
| Python support | Not specified |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Aging 427 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 330,746 / month, #7,531 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Intended Audience :: DevelopersProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.8Programming Language :: Python :: 3.9Programming Language :: Python :: Implementation :: CPythonProgramming Language :: Python :: Implementation :: PyPy |
Evidence: wait_for2-0.4.1-py3-none-any.whl
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