This is not only a bit faster, but also aligns with callers' expectations
better since we can legitimately have manifestdict's _flags set to '' instead
of unset.
hg perfmergecalculate -r .
before: ! wall 0.139582 comb 0.140000 user 0.140000 sys 0.000000 (best of 59)
after: ! wall 0.126154 comb 0.120000 user 0.120000 sys 0.000000 (best of 74)
hg perfmergecalculate -r .^
before: ! wall 0.236333 comb 0.240000 user 0.240000 sys 0.000000 (best of 36)
after: ! wall 0.212265 comb 0.210000 user 0.210000 sys 0.000000 (best of 45)
Given two dicts, diff returns a dict containing all the keys that are present
in one dict but not the other, or whose values are different between the
dicts. The values are pairs of the values from the dicts, with missing values
being represented as an optional argument, defaulting to None.
Given two dicts, join performs what is known as an outer join in relational
database land: it returns a dict containing all the keys across both dicts.
The values are pairs as above, except they aren't compared to see if they're
the same.
