compare grep result between target and its parent I found that typical case is that grep target is added at (*) revision in the tree shown below. +--- 1(*) --- 3 0 +--- 2 ------ 4 Now, I expect 'hg grep --all' to show only rev:1 which is first appearance of target line. But 'hg grep --all' will tell: target line dis-appeared at 3 => 4 target line appeared at 2 => 3 target line dis-appeared at 1 => 2 target line appeared at 0 => 1 because current 'hg grep' implementation compares not between target revision and its parent, but between neighbor revisions in walkthrough order. I checked performance of this patch by "hg grep --follow --all walkchangerevs" on whole Mercurial repo, and patched version could complete as fast as un-patched one.