convert: allow the converter_source to say "skip this revision" If getchanges returns a string, it's assumed to be the id of an already converted revision. We map the current revision to the same revision this converted revision was mapped to. To allow skipping a root revision, getchanges can return the special string 'hg-convert-skipped-revision' (a.k.a. common.SKIPREV), which hopefully won't clash with any real id. The converter_source is responsible for rewriting the parents of the commit objects to make sure the revision graph makes sense.

adding a
? a
adding a
A a
A a
? b
A a
A b
% should fail
b already tracked!
A a
A b
% should fail
a already tracked!
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
warning: conflicts during merge.
merging a
merging a failed!
0 files updated, 0 files merged, 0 files removed, 1 files unresolved
There are unresolved merges, you can redo the full merge using:
  hg update -C 2
  hg merge 1
M a
% should fail
a already tracked!
M a
% issue683
R a
M a