tests/test-exchange-obsmarkers-case-B7.t

rebase: add boolean config item rebase.store-source

This allows to use rebase without recording a rebase_source extra
field. This is useful for example to build a mirror converted from
another SCM (such as svn) by converting only new revisions, and
then incrementally add them to the destination by pulling from the
newly converted (unrelated) repo and rebasing the new revisions
onto the last old already stored changeset. Without this patch the
rebased changesets would always receive some rebase_source that
would depend on the particular history of the conversion process,
instead of only depending on the original source revisions.

This is used to implement a hg mirror repo of SvarDOS (a partially
nonfree but completely redistributable DOS distribution) in the
scripts at https://hg.pushbx.org/ecm/svardos.scr/

In particular, cre.sh creates an svn mirror, upd.sh recreates an
entire hg repo from the svn mirror (which takes too long to do in a
regular job), and akt.sh uses hg convert with the config item
convert.svn.startrev to incrementally convert only the two most
recent revisions already found in the mirror destination plus any
possible new revisions. If any are found, the temporary repo's
changesets are pulled into the destination (as changesets from an
unrelated repository). Then the changesets corresponding to the new
revisions are rebased onto the prior final changeset. (Finally, the
two remaining duplicates of the prior head and its parent are
stripped from the destination repository.)

Without this patch, the particular rebase_source extra field would
depend on the order and times at which akt.sh was used, instead of
only depending on the source repository. In other words, whatever
sequence of upd.sh and akt.sh is used at whatever times, it is
desired that the final output repositories always match each other
exactly.

============================================
Testing obsolescence markers push: Cases B.7
============================================

Mercurial pushes obsolescences markers relevant to the "pushed-set", the set of
all changesets that requested to be "in sync" after the push (even if they are
already on both side).

This test belongs to a series of tests checking such set is properly computed
and applied. This does not tests "obsmarkers" discovery capabilities.

Category B: pruning case
TestCase 7: Prune on non-targeted common changeset

B.7 Prune above non-targeted common changeset
=============================================

.. (very similar to B1, but the prune changeset is unknown on remote)
..
.. {{{
..     ⊗ B
..     |
..     ◕ A
..     |
..     ● O
.. }}}
..
.. Marker exist from:
..
..  * B (prune)
..
.. Command runs:
..
..  * hg push -r O
..
.. Expected exclude:
..
..  * B (prune)

Setup
-----

  $ . $TESTDIR/testlib/exchange-obsmarker-util.sh

Initial

  $ setuprepos B.7
  creating test repo for test case B.7
  - pulldest
  - main
  - pushdest
  cd into `main` and proceed with env setup
  $ cd main
  $ mkcommit A
  $ hg push -q ../pushdest
  $ hg push -q ../pulldest
  $ mkcommit B
  $ hg prune -qd '0 0' .
  $ hg log -G --hidden
  x  f6fbb35d8ac9 (draft): B
  |
  @  f5bc6836db60 (draft): A
  |
  o  a9bdc8b26820 (public): O
  
  $ inspect_obsmarkers
  obsstore content
  ================
  f6fbb35d8ac958bbe70035e4c789c18471cdc0af 0 {f5bc6836db60e308a17ba08bf050154ba9c4fad7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  $ cd ..
  $ cd ..

Actual Test
-------------------------------------

  $ dotest B.7 O
  ## Running testcase B.7
  # testing echange of "O" (a9bdc8b26820)
  ## initial state
  # obstore: main
  f6fbb35d8ac958bbe70035e4c789c18471cdc0af 0 {f5bc6836db60e308a17ba08bf050154ba9c4fad7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  # obstore: pulldest
  ## pushing "O" from main to pushdest
  pushing to pushdest
  searching for changes
  no changes found
  ## post push state
  # obstore: main
  f6fbb35d8ac958bbe70035e4c789c18471cdc0af 0 {f5bc6836db60e308a17ba08bf050154ba9c4fad7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  # obstore: pulldest
  ## pulling "a9bdc8b26820" from main into pulldest
  pulling from main
  no changes found
  ## post pull state
  # obstore: main
  f6fbb35d8ac958bbe70035e4c789c18471cdc0af 0 {f5bc6836db60e308a17ba08bf050154ba9c4fad7} (Thu Jan 01 00:00:00 1970 +0000) {'user': 'test'}
  # obstore: pushdest
  # obstore: pulldest