tests/test-merge9.t

largefiles: don't verify largefile hashes on servers when processing statlfile

When changesets referencing largefiles are pushed then the corresponding
largefiles will be pushed too - unless the target already has them. The client
will use statlfile to make sure it only sends largefiles that the target
doesn't have. The server would however on every statlfile check that the
content of the largefile had the expected hash. What should be cheap thus
became an expensive operation that trashed the disk and the cache.

Largefile hashes are already checked by putlfile before being stored on the
server. A server should thus be able to keep its largefile store free of
errors - even more than it can keep revlogs free of errors. Verification should
happen when running 'hg verify' locally on the server. Rehashing every
largefile on every remote stat is too expensive.

Clients will also stat lfiles before downloading them. When the server verified
the hash in stat it meant that it had to read the file twice to serve it.

With this change the server will assume its own hashes are ok without checking
them on every statlfile.

Some consequences of this change:
- in case of server side corruption the problem will be detected by the
  existing check on the client side - not on server side
- clients that could upload an uncorrupted largefile when pushing will no
  longer magically heal the server (and break hardlinks) - a client will now
  only upload its uncorrupted files after the corrupted file has been removed
  on the server side
- client side verify will no longer report corruption in files it doesn't have

(Issue3123 discussed related problems - and how they have been fixed.)

test that we don't interrupt the merge session if
a file-level merge failed

  $ hg init repo
  $ cd repo

  $ echo foo > foo
  $ echo a > bar
  $ hg ci -Am 'add foo'
  adding bar
  adding foo

  $ hg mv foo baz
  $ echo b >> bar
  $ echo quux > quux1
  $ hg ci -Am 'mv foo baz'
  adding quux1

  $ hg up -qC 0
  $ echo >> foo
  $ echo c >> bar
  $ echo quux > quux2
  $ hg ci -Am 'change foo'
  adding quux2
  created new head

test with the rename on the remote side
  $ HGMERGE=false hg merge
  merging bar
  merging bar failed!
  merging foo and baz to baz
  1 files updated, 1 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]
  $ hg resolve -l
  U bar
  R baz

test with the rename on the local side
  $ hg up -C 1
  3 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ HGMERGE=false hg merge
  merging bar
  merging bar failed!
  merging baz and foo to baz
  1 files updated, 1 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg update -C .' to abandon
  [1]

show unresolved
  $ hg resolve -l
  U bar
  R baz

unmark baz
  $ hg resolve -u baz

show
  $ hg resolve -l
  U bar
  U baz
  $ hg st
  M bar
  M baz
  M quux2
  ? bar.orig

re-resolve baz
  $ hg resolve baz
  merging baz and foo to baz

after resolve
  $ hg resolve -l
  U bar
  R baz

resolve all warning
  $ hg resolve
  abort: no files or directories specified; use --all to remerge all files
  [255]

resolve all
  $ hg resolve -a
  merging bar
  warning: conflicts during merge.
  merging bar incomplete! (edit conflicts, then use 'hg resolve --mark')
  [1]

after
  $ hg resolve -l
  U bar
  R baz

  $ cd ..