parsedate: understand "now" as a shortcut for the current time

export: clobber files with -o (bc) (issue3652) This violated user expectation. Updated the code to clobber files, but preserve the behavior of appending multiple patches requested in a single export. Includes tests.

merge: don't call copies.mergecopies unless we need to This reduces the amount of time we spend calculating when doing a clean non-merge update. In a large repo, the time dropped from 10.1 seconds to 3.4.

merge: rename p1 to wctx in manifestmerge This is always a workingctx, and this name is more in line with other functions in this module.

largefiles: fix test and check code

histedit: always abort with same message when working dir is wrong. Using only one message makes live easier for translators. The clearer error message was supposed by Augie Fackler.

histedit: report when revisions to edit are not ancestors of working dir Editing the history only is possible when the working dir is a descendant of the revisions to edit. When this happens explain it by writing abort: %s is not an ancestor of working directory

Merge

manifestmerge: handle abort on local unknown, remote created files This replaces the _checkunknown call in calculateupdates with a more performant version. On a repository with over 150,000 files, this speeds up an update by 0.6-0.8 seconds, which is up to 25%. This does not introduce any UI changes. There is existing test coverage for every case, mostly in test-merge*.t.

manifestmerge: pass in branchmerge and force separately This will be used in an upcoming patch.