tests/test-pull-pull-corruption2.t

dirstate: avoid normalizing letter case on icasefs for exact match (issue3340)

on icasefs, "hg qnew" fails to import changing letter case of filename
already occurred in working directory, for example:

    $ hg rename a tmp
    $ hg rename tmp A
    $ hg qnew casechange
    $ hg status
    R a
    $

"hg qnew" invokes 'dirstate.walk()' via 'localrepository.commit()'
with 'exact match' matching object having exact filenames of targets
in ones 'files()'.

current implementation of 'dirstate.walk()' always normalizes letter
case of filenames from 'match.files()' on icasefs, even though exact
matching is required.

then, files only different in letter case are treated as one file.

this patch prevents 'dirstate.walk()' from normalizing, if exact
matching is required, even on icasefs.

filenames for 'exact matching' are given not from user command line,
but from dirstate walk result, manifest of changecontext, patch files
or fixed list for specific system files (e.g.: '.hgtags').

in such case, case normalization should not be done, so this patch
works well.

Corrupt an hg repo with two pulls.
create one repo with a long history

  $ hg init source1
  $ cd source1
  $ touch foo
  $ hg add foo
  $ for i in 1 2 3 4 5 6 7 8 9 10; do
  >     echo $i >> foo
  >     hg ci -m $i
  > done
  $ cd ..

create a third repo to pull both other repos into it

  $ hg init version2
  $ hg -R version2 pull source1 &
  $ sleep 1
  pulling from source1
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 10 changes to 1 files
  (run 'hg update' to get a working copy)
  $ hg clone --pull -U version2 corrupted
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 10 changesets with 10 changes to 1 files
  $ wait
  $ hg -R corrupted verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 10 changesets, 10 total revisions
  $ hg -R version2 verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 10 changesets, 10 total revisions