tests/test-debugrename.t

pathencode: fix hashmangle short dir limit (issue3958)

The Python version of this (see mercurial/store.py:_hashencode) copies path
components up to a limit of maxshortdirslen bytes. The Python version does not
consider the initial "dh/" to be part of the this, though, while the C version
currently does. Adding len("dh/") == 3 to the limit for the C version brings it
in line with the Python version.

This was not caught by the randomized testing scheme in test-pathencode.py
because of a couple of flaws with the test. Upcoming patches will fix those
problems.

  $ hg init
  $ echo a > a
  $ hg ci -Am t
  adding a

  $ hg mv a b
  $ hg ci -Am t1
  $ hg debugrename b
  b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3

  $ hg mv b a
  $ hg ci -Am t2
  $ hg debugrename a
  a renamed from b:37d9b5d994eab34eda9c16b195ace52c7b129980

  $ hg debugrename --rev 1 b
  b renamed from a:b789fdd96dc2f3bd229c1dd8eedf0fc60e2b68e3