context: use new manifest.diff(clean=True) support This further simplifies the status code. This simplification comes at a slight performance cost for `hg export`. Before, on mozilla-central: perfmanifest tip ! wall 0.265977 comb 0.260000 user 0.240000 sys 0.020000 (best of 38) perftags ! result: 162 ! wall 0.007172 comb 0.010000 user 0.000000 sys 0.010000 (best of 403) perfstatus ! wall 0.422302 comb 0.420000 user 0.260000 sys 0.160000 (best of 24) hgperf export tip ! wall 0.148706 comb 0.150000 user 0.150000 sys 0.000000 (best of 65) after, same repo: perfmanifest tip ! wall 0.267143 comb 0.270000 user 0.250000 sys 0.020000 (best of 37) perftags ! result: 162 ! wall 0.006943 comb 0.010000 user 0.000000 sys 0.010000 (best of 397) perfstatus ! wall 0.411198 comb 0.410000 user 0.260000 sys 0.150000 (best of 24) hgperf export tip ! wall 0.173229 comb 0.170000 user 0.170000 sys 0.000000 (best of 55) The next set of patches introduces a new manifest type implemented almost entirely in C, and more than makes up for the performance hit incurred in this change.