manifest: document return type of readfast() I keep having to ponder out what readfast() means, and it always surprises me. Document the return type in the docstring so that future readers won't have to puzzle this out again.

archive: always use portable path component separators with subrepos The previous behavior when archiving a subrepo 's' on Windows was to internally name the file under it 's\file', due to the use of vfs.reljoin(). When printing the file list from the archive on Windows or Linux, the file was named 's\\file'. The archive extracted OK on Windows, but if the archive was brought to a Linux system, it created a file named 's\file' instead of a directory 's' containing 'file'. *.zip format achives seemed not to have the problem, but this was definitely an issue with *.tgz archives. Largefiles actually got this right, but a test is added to keep this from regressing. The subrepo-deep-nested-change.t test was repurposed to archive to a file, since there are several subsequent tests that archive to a directory. The output change is losing the filesystem prefix '../archive_lf' and not listing the directories 'sub1' and 'sub1/sub2'.

revset: narrow the subset using smartset operation in roots() We were manually creating a base with explicit subset testing. We should let smartset magic happen and optimise that logic if needed. benchmark show some massive speedup when "parents set" is huge and "subset" is small. revset: 42:68 and roots(42:tip) 0) wall 0.011322 comb 0.010000 user 0.010000 sys 0.000000 (best of 161) 1) wall 0.002282 comb 0.010000 user 0.010000 sys 0.000000 (best of 1082) Minor speedup in simple case (were fullreposet helps) revset: roots(0::tip) 0) wall 0.095688 comb 0.100000 user 0.100000 sys 0.000000 (best of 85) 1) wall 0.084448 comb 0.080000 user 0.080000 sys 0.000000 (best of 95) revset: roots((0:tip)::) 0) wall 0.146752 comb 0.140000 user 0.140000 sys 0.000000 (best of 58) 1) wall 0.143538 comb 0.140000 user 0.140000 sys 0.000000 (best of 59) And small overhead then the "parents set" is fairly complicated (transforming it into a revset once and for all appears to be faster). revset: roots((tip~100::) - (tip~100::tip)) 0) wall 0.004652 comb 0.010000 user 0.010000 sys 0.000000 (best of 544) 1) wall 0.004878 comb 0.010000 user 0.010000 sys 0.000000 (best of 479) revset: roots((0::) - (0::tip)) 0) wall 0.146587 comb 0.150000 user 0.150000 sys 0.000000 (best of 53) 1) wall 0.157192 comb 0.160000 user 0.160000 sys 0.000000 (best of 53) revset: first(roots((0::) - (0::tip))) 0) wall 0.152924 comb 0.150000 user 0.150000 sys 0.000000 (best of 57) 1) wall 0.153192 comb 0.160000 user 0.160000 sys 0.000000 (best of 55)