tests: demonstrate aborted rebase strips commits that didn't need rebasing

I haven't verified, but this has probably been broken ever since I
added the feature in 78496ac30025 (rebase: allow rebase even if some
revisions need no rebase (BC) (issue5422), 2017-05-11).

Differential Revision: https://phab.mercurial-scm.org/D2877

tests/test-rebase-partial.t

@@ -1,95 +1,125 b''
 Tests rebasing with part of the rebase set already in the
 destination (issue5422)
 
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > rebase=
   > drawdag=$TESTDIR/drawdag.py
   > 
   > [experimental]
   > evolution.createmarkers=True
   > evolution.allowunstable=True
   > 
   > [alias]
   > tglog = log -G --template "{rev}: {node|short} {desc}"
   > EOF
 
   $ rebasewithdag() {
   >   N=`$PYTHON -c "print($N+1)"`
   >   hg init repo$N && cd repo$N
   >   hg debugdrawdag
   >   hg rebase "$@" > _rebasetmp
   >   r=$?
   >   grep -v 'saved backup bundle' _rebasetmp
   >   [ $r -eq 0 ] && hg tglog
   >   cd ..
   >   return $r
   > }
 
 Rebase two commits, of which one is already in the right place
 
   $ rebasewithdag -r C+D -d B <<EOF
   > C
   > |
   > B D
   > |/
   > A
   > EOF
   rebasing 2:b18e25de2cf5 "D" (D)
   already rebased 3:26805aba1e60 "C" (C tip)
   o  4: fe3b4c6498fa D
   |
   | o  3: 26805aba1e60 C
   |/
   | x  2: b18e25de2cf5 D
   | |
   o |  1: 112478962961 B
   |/
   o  0: 426bada5c675 A
   
 Can collapse commits even if one is already in the right place
 
   $ rebasewithdag --collapse -r C+D -d B <<EOF
   > C
   > |
   > B D
   > |/
   > A
   > EOF
   rebasing 2:b18e25de2cf5 "D" (D)
   rebasing 3:26805aba1e60 "C" (C tip)
   o  4: a2493f4ace65 Collapsed revision
   |  * D
   |  * C
   | x  3: 26805aba1e60 C
   |/
   | x  2: b18e25de2cf5 D
   | |
   o |  1: 112478962961 B
   |/
   o  0: 426bada5c675 A
   
+Abort doesn't lose the commits that were already in the right place
+
+  $ hg init abort
+  $ cd abort
+  $ hg debugdrawdag <<EOF
+  > C
+  > |
+  > B D  # B/file = B
+  > |/   # D/file = D
+  > A
+  > EOF
+  $ hg rebase -r C+D -d B
+  rebasing 2:ef8c0fe0897b "D" (D)
+  merging file
+  warning: conflicts while merging file! (edit, then use 'hg resolve --mark')
+  unresolved conflicts (see hg resolve, then hg rebase --continue)
+  [1]
+  $ hg rebase --abort
+  saved backup bundle to $TESTTMP/abort/.hg/strip-backup/79f6d6ab7b14-cce2340e-backup.hg
+  rebase aborted
+BROKEN: C got stripped
+  $ hg tglog
+  o  2: ef8c0fe0897b D
+  |
+  | o  1: 594087dbaf71 B
+  |/
+  o  0: 426bada5c675 A
+  
+  $ cd ..
+
 Rebase with "holes". The commits after the hole should end up on the parent of
 the hole (B below), not on top of the destination (A).
 
   $ rebasewithdag -r B+D -d A <<EOF
   > D
   > |
   > C
   > |
   > B
   > |
   > A
   > EOF
   already rebased 1:112478962961 "B" (B)
   rebasing 3:f585351a92f8 "D" (D tip)
   o  4: 1e6da8103bc7 D
   |
   | x  3: f585351a92f8 D
   | |
   | o  2: 26805aba1e60 C
   |/
   o  1: 112478962961 B
   |
   o  0: 426bada5c675 A