view tests/test-install.t @ 18136:f23dea2b296e

copies: do not track backward copies, only renames (issue3739)

The inverse of a rename is a rename, but the inverse of a copy is not a copy.
Presenting it as such -- in particular, stuffing it into the same dict as real
copies -- causes bugs because other code starts believing the inverse copies
are real.

The only test whose output changes is test-mv-cp-st-diff.t. When a backwards
status -C command is run where a copy is involved, the inverse copy (which was
hitherto presented as a real copy) is no longer displayed.

Keeping track of inverse copies is useful in some situations -- composability
of diffs, for example, since adding "a" followed by an inverse copy "b" to "a"
is equivalent to a rename "b" to "a". However, representing them would require
a more complex data structure than the same dict in which real copies are also
stored.

hg debuginstall
  $ hg debuginstall
  checking encoding (ascii)...
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
  no problems detected

hg debuginstall with no username
  $ HGUSER= hg debuginstall
  checking encoding (ascii)...
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
   no username supplied (see "hg help config")
   (specify a username in your configuration file)
  1 problems detected, please check your install!
  [1]