bitfielddepends

Bitfielddepends is a mechanism in software configuration and packaging systems for encoding dependencies that depend on the values of a bitfield. A bitfield is an integer whose bits represent binary feature flags. Bitfielddepends allows a single manifest to express multiple conditional dependencies without enumerating every feature combination.

In a bitfielddepends model, rules specify a bitmask, a required value, and a list of dependencies that apply when (config & mask) equals value. The resolver evaluates the rules against the configured bitfield and aggregates the required packages. Some implementations support rule precedence to resolve conflicts when multiple rules match.

Example usage can involve feature flags such as GUI and networking. A rule may require a graphics library when the GUI bit is set, and an additional networking dependency when both GUI and networking bits are set. This enables compact manifests in modular systems with many optional components, where dependencies scale with feature combinations rather than with individual options.

Benefits of bitfielddepends include reduced manifest size and potentially faster dependency evaluation in highly modular builds. Challenges include reduced readability and increased difficulty in debugging, as well as ensuring deterministic resolution as the number of bits grows and interactions between rules become more complex.

Bitfielddepends is related to broader concepts such as feature flags and conditional dependencies. It shares a goal with mask-based configuration approaches used in embedded software and some package management ecosystems: to express complex, conditional requirements in a compact, machine-readable form. See also feature flag, conditional dependency, bitfield.