Similar to what was explained in the previous commit, the diff code
expected copy source to be in "ctx1", which is not always the case
during a merge. This has been broken since before hg 2.0.
Also similar to the previous commit, we fix the problem by fixing up
the copy dict.
During a merge, if the user removes a file that came from parent 2 and
did not exist in parent 1, the file's status will be "removed". This
surprises the diff code, which crashes because it expects removed
files exist in parent 1. This has been broken since ff976121fb34
(trydiff: use 'not in addedset' for symmetry with 'not in removedset',
2014-12-23).
Fix by fixing up the list of removed file, similar to how we currently
fix up the list of modified and added files during a merge.
Many tests fixed the commit date of their changesets at '1000000 0' or
similar. However testing with "Mon Jan 12 13:46:40 1970 +0000" is not
better than testing with "Thu Jan 01 00:00:00 1970 +0000", which is
the default run-tests.py installs.
Removing the unnecessary flag removes some clutter and will hopefully
make it clearer what the tests are really trying to test. Some tests
did not even change their output when the dates were changed, in which
case the -d flag was truly irrelevant.
Dates used in sequence (such as '0 0', '1 0', etc...) were left alone
since they may make the test easier to understand.
