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
hg --debug init
echo this is a1 > a
hg add a
hg commit -m0 -d "1000000 0"
echo this is b1 > b
hg add b
hg commit -m1 -d "1000000 0"
hg manifest --debug 1
echo this is c1 > c
hg rawcommit -p 1 -d "1000000 0" -m2 c
hg manifest --debug 2
hg -v parents
rm b
hg rawcommit -p 2 -d "1000000 0" -m3 b
hg manifest --debug 3
hg -v parents
echo this is a22 > a
hg rawcommit -p 3 -d "1000000 0" -m4 a
hg manifest --debug 4
hg -v parents
echo this is c22 > c
hg rawcommit -p 1 -d "1000000 0" -m5 c
hg manifest --debug 5
hg -v parents
# merge, but no files changed
hg rawcommit -p 4 -p 5 -d "1000000 0" -m6
hg manifest --debug 6
hg -v parents
# no changes what-so-ever
hg rawcommit -p 6 -d "1000000 0" -m7
hg manifest --debug 7
hg -v parents