Issues #27 and #28.

deriveCandidateHints walked each check-in's whole S-card tree and its parent's, for every check-in. Shared subtrees can never pair -- an unchanged node has the same rid on both sides, so pairAgainstParent skips it -- and their blobs were already recorded at introduction, which Pass 2 relies on only as a distinct set (it compacts with dedupSortedRids). So the walk now descends lockstep and prunes any subtree whose S node is the same artifact in both. O(check-ins x tree) becomes O(check-ins x changed paths): sub-manifest loads drop 56 percent on libfossil, to near the distinct-node floor, and the ratio grows with tree size.

The visits that remain were re-inflating. contentOfEntry memoized only .delta frames, so a .zlib sub-manifest re-inflated on every visit -- which is why a pack profile is dominated by flate.Decompress.streamInner rather than by tree-walk arithmetic. PlaintextCache gains memoize_undeltaed, off by default because a linear sweep that reads each artifact once would only duplicate bytes, and opted into by this walk, which revisits.

Output is byte-identical: the wapp store hashes unchanged, and a 189,251 artifact fossil-corpus repack is a fixpoint at 176,143,384 bytes with the same 146,059 re-deltaed.

test 3495/3495, gate, dst 6x1000, e2e 718/718, git-import-e2e, git-import-cli. check-in: a89b63ad05 user: dmestas tags: sub-manifest