sentinel

library1.0.0pypypi✓ verified 83d ago

Create sentinel objects, akin to None, NotImplemented, Ellipsis. Provides a simple way to define unique sentinel values for signaling special conditions (e.g., default arguments, missing data). Current version: 1.0.0. Release cadence: infrequent, stable.

serialization

pip install sentinel

github ↗package ↗

INSTALL

IMPORT

SIG · SENTINEL

sentinel

serializationpythonv1.0.0

Install

1.6s avg

Import

—

Disk

16MB

Pass rate

10/ 10

Env Coverage10 / 10

glibc

3.9–3.13

musl

3.9–3.13

Install & Compatibility

Where this runs

tested against v1.0.0 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

py 3.10–3.95 runs

installs and imports cleanly · install 0.0s · import 0.000s · 17.8MB

glibc

py 3.10–3.95 runs

installs and imports cleanly · install 1.6s · import 0.000s · 18MB

16MB installed

● package 16MB

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

create

✓ from sentinel import create

✗ from sentinel import Sentinel

inspect

✓ from sentinel import inspect

Any

✓ from sentinel import Any

Creates a sentinel object to use as a default argument marker.

from sentinel import Sentinel # Create a unique sentinel NotGiven = Sentinel('NotGiven') def get_value(key, default=NotGiven): if default is NotGiven: print('No default provided') else: print(f'Default is {default}') get_value('foo') get_value('foo', default='bar')

Debug

Known issues

gotchaSentinel instances are not singletons by default; each call to Sentinel('name') creates a new instance. Use a module-level constant to maintain identity.

fix

Always assign the sentinel to a module-level variable (e.g., _MISSING = Sentinel('MISSING')) and import that variable.

affects: >=0.1.0

gotchaSentinel objects cannot be pickled by default. Attempting to pickle a sentinel will raise a PicklingError.

fix

If pickling is needed, use sentinel's __reduce__ method or define a custom sentinel class.

affects: >=0.1.0

gotchaSentinel instances compare by identity, not value. Using == may give unexpected results if the sentinel is not the exact same object.

fix

Always use 'is' for comparison, not '=='.

affects: >=0.1.0

Upgrade

Version history

1.0.0latest on PyPI · released Jul 23, 2022

Audit

Dependencies

sixoptionalUsed for Python 2/3 compatibility (though library requires >=3.6, included for historical reasons)

Agent activity

9 hits · last 30 days

node

Amazon

Resources

githubhttps://github.com/eddieantonio/sentinel ↗

packagehttps://pypi.org/project/sentinel/ ↗