dirstate: narrow gathering of parent data
The parent data are only going to be useful is the file might be clean. And it
might only be clean if it is tracked in both p1 and the working copy.
Differential Revision: https://phab.mercurial-scm.org/D11584
$ cat >> $HGRCPATH <<EOF
> [extensions]
> drawdag=$TESTDIR/drawdag.py
> bruterebase=$TESTDIR/bruterebase.py
> [experimental]
> evolution.createmarkers=True
> evolution.allowunstable=True
> EOF
$ init() {
> N=`expr ${N:-0} + 1`
> cd $TESTTMP && hg init repo$N && cd repo$N
> hg debugdrawdag
> }
Source looks like "N"
$ init <<'EOS'
> C D
> |\|
> A B Z
> EOS
$ hg debugbruterebase 'all()-Z' Z
A: A':Z
B: B':Z
AB: A':Z B':Z
C: ABORT: cannot rebase 3:a35c07e8a2a4 without moving at least one of its parents
AC: A':Z C':A'B
BC: B':Z C':B'A
ABC: A':Z B':Z C':A'B'
D: D':Z
AD: A':Z D':Z
BD: B':Z D':B'
ABD: A':Z B':Z D':B'
CD: ABORT: cannot rebase 3:a35c07e8a2a4 without moving at least one of its parents
ACD: A':Z C':A'B D':Z
BCD: B':Z C':B'A D':B'
ABCD: A':Z B':Z C':A'B' D':B'
Moving backwards
$ init <<'EOS'
> C
> |\
> A B
> |
> Z
> EOS
$ hg debugbruterebase 'all()-Z' Z
B: B':Z
A:
BA: B':Z
C: ABORT: cannot rebase 3:b8d7149b562b without moving at least one of its parents
BC: B':Z C':B'A
AC:
BAC: B':Z C':B'A