libpkgapply

libpkgapply is the Zeppe-Lin C++17 library for applying one accepted libpkgplan package-operation plan to one managed target.

Its authority is deliberately narrow:

libpkgplan    immutable intended transition
libpkgapply   observed application effects and recovery evidence
libpkgstate   durable installed truth and state publication
pkgman        transaction composition and final resolution

Implemented foundation

The current development tree provides the immutable and live-authority foundation required before target mutation is admitted:

• strict domain-separated SHA-256 application identities;
• immutable target application contexts and execution controls;
• operation-specific installation, upgrade, and removal requests retaining the exact accepted libpkgplan objects;
• complete lease-bound installed-state projections;
• rich completed filesystem-object facts with explicit known, unknown, and not-applicable fields;
• path consequences bound back to exact plan decisions and incoming image entry identifiers;
• typed application outcomes, recovery states, durability profiles, receipts, and publication-eligible completed evidence; and
• validation of caller-held target mutation leases against the target context, exclusion domain, acquisition instance, and state projection; and
• constrained backend mechanism contracts for exact observations, private payload staging, old-object capture, active and rejected effects, recovery, durability synchronization, and journal publication; and
• exact admission checks binding plan schema and kind, target, backend, capabilities, outer lease, installed snapshot, ownership inventory, path owner closure, archive bytes, image, inspection receipt, and image entry IDs; and
• fresh filesystem-precondition checks where every planning-time fact that was known must remain known and equal, while additional current facts are retained as richer evidence rather than rejected as drift; and
• exact incoming regular-payload closure derivation, including deduplicated hard-link anchors and separate active versus rejected consumers; and
• pre-mutation old-object capture derivation that merges rejected staging and selected recovery needs without admitting absent or retained paths; and
• deterministic safe mechanism schedules that place old-object capture before mutation, regular payload staging in archive order, rejected publication before destructive active effects, incoming directories before descendants, child removals before parent cleanup, hard-link anchors before links, and final observation after all planned effects.

No concrete filesystem actuator, archive replay coordinator, journal storage backend, or POSIX backend is present yet. The public model rejects inconsistent evidence before those effectful layers are introduced.

Authority boundary

The completed library will:

• consume an accepted installation, upgrade, or removal plan;
• require one caller-held target mutation lease;
• revalidate state and filesystem preconditions under that lease;
• stage exact incoming payloads through libpkgimage;
• execute only effects selected by the accepted plan;
• journal mutation attempts and recovery material;
• return an immutable application receipt; and
• return completed application evidence only after complete success.

The library will not:

• select packages or solve dependencies;
• parse package-manager configuration;
• reinterpret preserve, reject, omit, or ownership policy;
• discover or reopen package archives by pathname;
• execute unbound lifecycle declarations;
• construct libpkgstate installed objects;
• publish installed state; or
• claim global filesystem and state atomicity.

Requirements

Build-time requirements are:

• a C++17 compiler;
• Meson 1.2.0 or later;
• Ninja;
• pkg-config;
• libpkgimage 0.3.0 or later;
• libpkgplan 0.1.0 or later; and
• OpenSSL libcrypto with SHA-256 EVP support.

Building

Shared library:

meson setup build
meson compile -C build
meson test -C build --print-errorlogs

Static library with static dependencies:

meson setup build-static \
  -Ddefault_library=static \
  -Dlink_mode=static
meson compile -C build-static
meson test -C build-static --print-errorlogs

default_library=both is intentionally unsupported. Shared and static artifacts are qualified as separate builds with matching dependency linkage.

Development doctrine

Version 0.1.0 is being built contract-first. Effectful code is admitted only with direct failure, stale-state, journal, recovery, and identity tests.

See DESIGN.md for the normative authority and sequencing model and TESTING.md for release qualification.