tests/test-patch-offset.t

tests: avoid referring to pvec in demandimport test

Nothing else currently uses pvec, so we may want to delete it (but
Augie Fackler says he may want to use it). To enable deletion, this
patch replaces it by the error module in the demandimport test (any
module works). However, since the error module had already been loaded
at this point in the test (via the util module), I moved it earlier in
the test so it's still not loaded (although I'm not sure if that's
even relevant to the test).

Differential Revision: https://phab.mercurial-scm.org/D2287

  $ cat > writepatterns.py <<EOF
  > import sys
  > 
  > path = sys.argv[1]
  > patterns = sys.argv[2:]
  > 
  > fp = open(path, 'wb')
  > for pattern in patterns:
  >     count = int(pattern[0:-1])
  >     char = pattern[-1] + '\n'
  >     fp.write(char*count)
  > fp.close()
  > EOF

prepare repo

  $ hg init a
  $ cd a

These initial lines of Xs were not in the original file used to generate
the patch.  So all the patch hunks need to be applied to a constant offset
within this file.  If the offset isn't tracked then the hunks can be
applied to the wrong lines of this file.

  $ $PYTHON ../writepatterns.py a 34X 10A 1B 10A 1C 10A 1B 10A 1D 10A 1B 10A 1E 10A 1B 10A
  $ hg commit -Am adda
  adding a

This is a cleaner patch generated via diff
In this case it reproduces the problem when
the output of hg export does not
import patch

  $ hg import -v -m 'b' -d '2 0' - <<EOF
  > --- a/a	2009-12-08 19:26:17.000000000 -0800
  > +++ b/a	2009-12-08 19:26:17.000000000 -0800
  > @@ -9,7 +9,7 @@
  >  A
  >  A
  >  B
  > -A
  > +a
  >  A
  >  A
  >  A
  > @@ -53,7 +53,7 @@
  >  A
  >  A
  >  B
  > -A
  > +a
  >  A
  >  A
  >  A
  > @@ -75,7 +75,7 @@
  >  A
  >  A
  >  B
  > -A
  > +a
  >  A
  >  A
  >  A
  > EOF
  applying patch from stdin
  patching file a
  Hunk #1 succeeded at 43 (offset 34 lines).
  Hunk #2 succeeded at 87 (offset 34 lines).
  Hunk #3 succeeded at 109 (offset 34 lines).
  committing files:
  a
  committing manifest
  committing changelog
  created 189885cecb41

compare imported changes against reference file

  $ $PYTHON ../writepatterns.py aref 34X 10A 1B 1a 9A 1C 10A 1B 10A 1D 10A 1B 1a 9A 1E 10A 1B 1a 9A
  $ diff aref a

  $ cd ..