similar: sort files not by object id but by path for stable result Perhaps the original implementation would want to sort added/removed files alphabetically, but actually it did sort fctx objects by memory location. This patch removes the use of set()s in order to preserve the order of added/removed files. addedfiles.remove() becomes quadratic, but its cost appears not dominant. Anyway, the quadratic behavior will be eliminated by the next patch. Benchmark with 50k added/removed files, on tmpfs: $ mkdir src $ for n in `seq 0 49`; do > mkdir `printf src/%02d $n` > done $ for n in `seq 0 49999`; do > f=`printf src/%02d/%05d $(($n/1000)) $n` > dd if=/dev/urandom of=$f bs=8k count=1 status=none > done $ hg ci -qAm 'add 50k files of random content' $ mv src dest $ hg addremove --dry-run --time -q original: real 16.550 secs (user 15.000+0.000 sys 1.540+0.000) this patch: real 16.730 secs (user 15.280+0.000 sys 1.440+0.000)