This does not make much sense, because if common-unique lines swallow their neighboring ones, they count less, and another bad, shorter sequence may gain more weight than a very long sequence that was combined to just one common-unique chunk. It also much simplifies the code and avoids bugs we had to implement complex fixes for before.

In practice, recursion is already limited by our Myers max-effort cut and this heuristic should generally provide a better split than a limit on the number of diff boxes. A recursion limit is only required for diff configs that do not include the Myers algorithm, which we currently don't have. Discussed with Neels

discussed with Neels

Adjust labels used in diff output accordingly; non-existent files should have the label "/dev/null"

ok millert stsp

This line appears as a context line with regular diff(1) and git diff: crd->crd_key = sd->mds.mdd_crypto.scr_key[0]; [[[ + crd->crd_alg = sd->mds.mdd_crypto.scr_alg; + crd->crd_klen = sd->mds.mdd_crypto.scr_klen; crd->crd_key = sd->mds.mdd_crypto.scr_key[0]; - bcopy(&blk, crd->crd_iv, sizeof(blk)); + memcpy(crd->crd_iv, &blkno, sizeof(blkno)); ]]] Our diff produces a different result where this context line is both deleted and added: [[[ - crd->crd_alg = CRYPTO_AES_XTS; + crd->crd_alg = sd->mds.mdd_crypto.scr_alg; + crd->crd_klen = sd->mds.mdd_crypto.scr_klen; + crd->crd_key = sd->mds.mdd_crypto.scr_key[0]; + memcpy(crd->crd_iv, &blkno, sizeof(blkno)); + } - switch (sd->mds.mdd_crypto.scr_meta->scm_alg) { - case SR_CRYPTOA_AES_XTS_128: - crd->crd_klen = 256; - break; - case SR_CRYPTOA_AES_XTS_256: - crd->crd_klen = 512; - break; - default: - goto unwind; - } - crd->crd_key = sd->mds.mdd_crypto.scr_key[0]; - bcopy(&blk, crd->crd_iv, sizeof(blk)); - } - crwu->cr_wu = wu; - crwu->cr_crp->crp_opaque = crwu; - return (crwu); ]]]

uncovers errors related to placing minus chunks above already added plus chunks.