tests/test-convert-bzr-directories.out

prepush: add more precise error messages

Part of the patch is from [e-mail]

- indicate the branch name where there are multiple heads
- give better advice when hitting a possible race, where new heads are added
  between discovery and the call to branchmap(). In that case, asking the user
  to merge isn't helpful, since only remote has the changes.

% empty directory
initializing destination source-hg repository
scanning source...
sorting...
converting...
2 Initial add
1 Empty directory added
0 Added file into directory
% manifest of 1
644   a
% manifest of tip
644   a
644   empty/something
% directory renames
tpyo => typo
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Added directory
0 Oops, typo
% manifest of 0
644   tpyo/something
% manifest of tip
644   typo/something
% nested directory renames
firstlevel/secondlevel => secondlevel
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Added nested directories
0 Moved secondlevel one level up
% manifest of tip
644   secondlevel/file
644   secondlevel/thirdlevel/stuff
% directory remove
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Added directory
0 Removed directory
% manifest of 0
644   src/sourcecode
% manifest of tip
% directory replace
first/file => second/file
first => third
initializing destination source-hg repository
scanning source...
sorting...
converting...
1 Initial layout
0 Some conflicting moves
% manifest of tip
644   second/file
644   second/something
644   third/dummy