view tests/test-parseindex.t @ 22284:72b378658cff

largefiles: restore standins from non branch-tip parent at rollback correctly

Before this patch, "hg rollback" can't restore standins correclty, if:

  - old parent of the working directory is rollback-ed, and
  - new parent of the working directory is not branch-tip

"overriderollback" uses "merge.update" as a kind of "revert" utility
to restore only standins with "node=None", and this makes
"merge.update" choose "branch-tip" revision as the updating target
unexpectedly.

Then, "merge.update" restores standins from the branch-tip revision
regardless of the parent of the working directory after rollback and
this may cause unexpected behavior.

This patch invokes "merge.update" with "node='.'" to restore standins
from the parent revision of the working directory.

In fact, this "merge.update" invocation will be replaced in the
subsequent patch to fix another problem, but this change is usefull to
inform reason why such complicated case should be tested.

revlog.parseindex must be able to parse the index file even if
an index entry is split between two 64k blocks.  The ideal test
would be to create an index file with inline data where
64k < size < 64k + 64 (64k is the size of the read buffer, 64 is
the size of an index entry) and with an index entry starting right
before the 64k block boundary, and try to read it.
We approximate that by reducing the read buffer to 1 byte.

  $ hg init a
  $ cd a
  $ echo abc > foo
  $ hg add foo
  $ hg commit -m 'add foo'
  $ echo >> foo
  $ hg commit -m 'change foo'
  $ hg log -r 0:
  changeset:   0:7c31755bf9b5
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     add foo
  
  changeset:   1:26333235a41c
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     change foo
  
  $ cat >> test.py << EOF
  > from mercurial import changelog, scmutil
  > from mercurial.node import *
  > 
  > class singlebyteread(object):
  >     def __init__(self, real):
  >         self.real = real
  > 
  >     def read(self, size=-1):
  >         if size == 65536:
  >             size = 1
  >         return self.real.read(size)
  > 
  >     def __getattr__(self, key):
  >         return getattr(self.real, key)
  > 
  > def opener(*args):
  >     o = scmutil.opener(*args)
  >     def wrapper(*a):
  >         f = o(*a)
  >         return singlebyteread(f)
  >     return wrapper
  > 
  > cl = changelog.changelog(opener('.hg/store'))
  > print len(cl), 'revisions:'
  > for r in cl:
  >     print short(cl.node(r))
  > EOF
  $ python test.py
  2 revisions:
  7c31755bf9b5
  26333235a41c

  $ cd ..