Replaces the naive task-5.1 stopgap with the real restore contract:
detects legacy vs entity-bearing checkpoints by remaining file size;
restores every job then every queue status via restore_job/
restore_queue_state, in file order, with bounds-checked length-prefixed
reads; only after every entity restores successfully does
current_lsn/checkpoint_lsn commit to the checkpoint's position. Every
failure path (bounds check, decode, restore error, unrecognized
format_version) returns before that single commit point -- position is
provably untouched on failure, never partially advanced.
Also fixes the pre-existing restore_job decode leak (job.c): job_init
deep-copies submit (never nulled) and MOVE_PTRs allocs/pidinfo/
pend_reasons (nulled on the one path that runs) -- free_Job(&j) is safe
unconditionally on every reachable return path (EEXIST early-return,
create_job success, create_job failure), verified against the exact
generated free_*_ptr null-check guards.
Two pre-existing test_config_repl.c wire-protocol tests needed their
synthetic garbage snapshot bodies updated to a well-formed empty-entity
tail, since load_snapshot now genuinely parses past the legacy header
(previously ignored); their actual assertions (chunk-reassembly
correctness) are unchanged.
This is the exact function/contract that caused task 2.2's rejection
(position advancing before restore validated). Independent review
traced the memory-safety fix through the generated capnp code field-by-
field, confirmed the test_config_repl.c change doesn't weaken any
assertion, and confirmed restore_queue_state's ENOENT-aborts-the-whole-
checkpoint behavior is faithful to design.md's unconditional contract
(flagged as a watch-item for task 7.1's soak, not a defect).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JDYFbrgyDHbvNYcxApKhrX
Rongsong Shen
9fdb6778d4