alias: make alias command lazily resolved With many aliases, resolving them could have some visible overhead. Below is part of traceprof [1] output of `hg bookmark --hidden`: (time unit: ms) 37 \ addaliases dispatch.py:526 37 | __init__ (60 times) dispatch.py:402 33 | findcmd (108 times) cmdutil.py:721 16 | findpossible (49 times) cmdutil.py:683 It may get better by optimizing `findcmd` to do a bisect, but we don't really need to resolve an alias if it's not used, so let's make those command entries lazy. After this patch, `addalias` takes less than 1ms. .. perf:: improved performance when many aliases are defined [1]: https://bitbucket.org/facebook/hg-experimental/src/9aca0dbdbdfc48457e5d2581ca2d6e662fced2e6/hgext3rd/traceprof.pyx Differential Revision: https://phab.mercurial-scm.org/D805