transactions: add version number to journal.backupfiles The transaction format will be changing a bit over the next releases, so let's go ahead and add a version number to make backwards compatibility easier. This whole file format was broken prior to 3.2 (see previous patch), so changing it now is pretty low risk.

transactions: fix hg recover with fncache backups The transaction backupfiles logic was broken for 'hg recover'. The file format is XXX\0XXX\0YYY\0YYY\0 but the parser did a couple things wrong. 1) It went one step beyond the final \0 and tried to read past the end of the array. 2) array[i:i+1] returns a single item, instead of two items as intended. Added a test to catch it, which turns out to be the first actual 'hg recover' test.

revset: have rev() drop out-of-range or filtered rev explicitly (issue4396) The recent optimization of "and" operation relies on the assumption that the rhs set does not contain invalid revisions. So rev() has to remove invalid revisions. This is still faster than using `.filter(lambda r: r == l)`. revset #0: rev(25) 0) wall 0.026341 comb 0.020000 user 0.020000 sys 0.000000 (best of 113) 1) wall 0.000038 comb 0.000000 user 0.000000 sys 0.000000 (best of 66567) 2) wall 0.000062 comb 0.000000 user 0.000000 sys 0.000000 (best of 43699) (0: bbf4f3dfd700^, 1: 3.2-rc, 2: this patch)