nab-resolver
Generic PubGrub dependency-resolver core
Decision gist · record as of 2026-08-14
Yes, if you are building a package resolver or constraint-satisfaction system. The low install friction, zero runtime dependencies, active maintenance, and permissive license make it a solid foundation. Not relevant for end users of Python packages—use nab or nab-provider instead.AI-flagged interpretation of the facts on this page — verify before relying
Before you install
- Requires Python 3.10 or later.
- Caller must implement the ResolverProvider protocol with domain-specific logic.
- Low friction: pure Python, no runtime dependencies, and actively maintained with a recent release.
License · maintenance · safety
MIT (permissive) — MIT license permits unrestricted use, modification, and distribution with minimal attribution requirements.
last release 2026-08-14 (0 days) · last repo commit 2026-08-14 · 24 stars
0 known vulnerabilities (OSV.dev, 2026-08-14) · 422,340 downloads/mo, #6,783 on PyPI
Alternatives
Verify before relying
from nab_resolver.resolver import Resolver, ResolverProvider
from nab_resolver.types import Term, Incompatibility
# Implement ResolverProvider with your domain logic
class MyProvider(ResolverProvider):
def choose_package_version(self, term): ...
def get_incompatibilities(self, term): ...
resolver = Resolver(MyProvider())
solution = resolver.resolve(root_term)- Whether the resolver handles cyclic dependencies or other edge cases beyond what the public API documentation implies.
- Performance characteristics and scalability limits for large dependency graphs.
What it is and what it does
nab-resolver is a generic dependency-resolution engine built on PubGrub algorithms. It provides the core constraint-solving logic without any Python-specific knowledge, making it suitable for embedding in resolvers for any package ecosystem. The package exports a ResolverProvider protocol and a Resolver class that callers parameterize with their own domain logic—defining how to fetch versions, check compatibility, and report requirements.
It is intended as a library for developers building package resolvers, not as a standalone tool. The Python-specific provider lives in nab-provider, and the user-facing CLI is in nab. The resolver itself is a SAT-style solver core: you supply it with a protocol implementation, and it returns a solution or raises ResolutionError. It has no runtime dependencies beyond the standard library.
Use it for
- Embed the resolver in a custom package manager for a non-Python ecosystem.
- Build a dependency resolver for a domain-specific package format or language.
- Implement version constraint solving in a build tool or deployment system.
- Test or prototype dependency-resolution algorithms without writing a full resolver from scratch.
Worth the install?
AI-flagged interpretation of the facts on this page. Verify before relying on it.
Yes, if you are building a package resolver or constraint-satisfaction system.
The low install friction, zero runtime dependencies, active maintenance, and permissive license make it a solid foundation. Not relevant for end users of Python packages—use nab or nab-provider instead.
Install
nab-resolver on PyPI
Before you install
Low friction: pure Python, no runtime dependencies, and actively maintained with a recent release. Supports Python 3.10 through 3.14.
Requires Python 3.10 or later. Caller must implement the ResolverProvider protocol with domain-specific logic.
License in practice
MIT license permits unrestricted use, modification, and distribution with minimal attribution requirements.
Quickstart
from nab_resolver.resolver import Resolver, ResolverProvider
from nab_resolver.types import Term, Incompatibility
# Implement ResolverProvider with your domain logic
class MyProvider(ResolverProvider):
def choose_package_version(self, term): ...
def get_incompatibilities(self, term): ...
resolver = Resolver(MyProvider())
solution = resolver.resolve(root_term)Verify before relying
- Whether the resolver handles cyclic dependencies or other edge cases beyond what the public API documentation implies.
- Performance characteristics and scalability limits for large dependency graphs.
Package facts
| License | MIT permissive |
| Python support | Supports the current Python release >=3.10 |
| Install friction | Low. Pure-Python wheel |
| Runtime dependencies | None |
| Maintenance | Actively maintained 0 days since the last release |
| Last repo commit | |
| First released | |
| Downloads | 422,340 / month, #6,783 on PyPI 30-day window, as of 2026-08-14 |
| Known vulnerabilities | None known OSV.dev, checked 2026-08-14 |
| Classifiers | Development Status :: 4 - BetaProgramming Language :: Python :: 3Programming Language :: Python :: 3.10Programming Language :: Python :: 3.11Programming Language :: Python :: 3.12Programming Language :: Python :: 3.13Programming Language :: Python :: 3.14Typing :: Typed |
Evidence: nab_resolver-0.0.14-py3-none-any.whl
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See also nab-python · resolvelib · simplesat · claripy · kiwisolver · python-constraint · aiohttp-asyncmdnsresolver · pycosat · nab-index · sceptre-cmd-resolver