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.
#!/bin/sh
mkdir t
cd t
hg init
echo This is file a1 > a
echo This is file b1 > b
hg add a b
hg commit -m "commit #0" -d "1000000 0"
echo This is file b22 > b
hg commit -m"comment #1" -d "1000000 0"
hg update 0
rm b
hg commit -A -m"comment #2" -d "1000000 0"
# in theory, we shouldn't need the "-y" below, but it prevents
# this test from hanging when "hg update" erroneously prompts the
# user for "keep or delete"
hg update -y 1
exit 0