annotate tests/test-evolve-wdir.t @ 5777:c5dfbbe4363d

evolve: when relocating, optionally first try to do it using in-memory merge

This patch adds a config option to let run evolve's relocation step
using in-memory merge. It is disabled by default. When the option is
on, the relocation is first attempted in memory. If that fails because
of merge conflicts, it retries that commit in the working copy.

There are a few reasons that I made it configurable. The most
important one is that the precommit hook won't trigger when using
in-memory merge. Another reason is that it lets us roll out the
feature slowly to our users at Google.

For now, we also update the working copy after creating the commit (in the
successful case, when there are no merge conflicts). The next patch will make it
so we don't do that update.

Because of the unnecessary working-copy update, this patch doesn't
provide any benefit on its own. Evolving 29 commits that each change
one line in the hg slows down from ~4.5s to ~4.8s when the config
option is on.

I've added `#testcases inmemory ondisk` to select `.t` files. Almost
all differences are because of the new "hit merge conflicts" message
and retrying the merge. There's also one difference in
`test-stabilize-order.t` caused by the different order of working copy
updates (we now update the working copy at the end).

===============================================
Testing evolution of obsolete working directory
===============================================

Pulling changes from other repos can make your working directory parent (wdir)
obsolete, most probably because now it has a new successor. But there are
other cases as well where it might be pruned with no successors or split
in multiple changesets etc.

This test file deals with all the possible cases for the evolution from an
obsolete working directory parent.

.. Case A: obsolete wdp with single successor
..     Resolution : simply update to the successor
..
.. Case B: obsolete wdp with no successor (simply pruned)
..     Resolution : update to a not-dead ancestor
..
.. Case C: obsolete wdp with multiple successor (divergence rewriting)
..     Resolution : #TODO: not handled yet
..
.. Case D: obsolete wdp with multiple successor (split rewriting)
..     Resolution : #TODO: not handled yet

A. Obsolete wdp with single successor
-------------------------------------

Setup
  $ . $TESTDIR/testlib/common.sh
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > evolve=
  > rebase=
  > [alias]
  > glog = log --graph --template "{rev}:{node|short} ({phase}): {desc|firstline} {if(troubles, '[{troubles}]')}\n"
  > EOF

#testcases inmemory ondisk
#if inmemory
  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > evolution.in-memory = yes
  > EOF
#endif

  $ hg init repo
  $ cd repo
  $ mkcommit c_A
  $ mkcommit c_B
  $ hg amend -m "u_B"
  $ hg up -r 'desc(c_B)' --hidden
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 707ee88b2870
  (hidden revision '707ee88b2870' was rewritten as: 9bf151312dec)
  working directory parent is obsolete! (707ee88b2870)
  (use 'hg evolve' to update to its successor: 9bf151312dec)

  $ hg evolve
  update:[2] u_B
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  working directory is now at 9bf151312dec
  $ hg glog
  @  2:9bf151312dec (draft): u_B
  |
  o  0:9f0188af4c58 (draft): c_A
  

B. Obsolete wdp with no successor
---------------------------------

  $ hg prune .
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  working directory is now at 9f0188af4c58
  1 changesets pruned
  $ hg up -r 'desc(c_B)' --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 707ee88b2870
  (hidden revision '707ee88b2870' is pruned)
  working directory parent is obsolete! (707ee88b2870)
  (use 'hg evolve' to update to its parent successor)

  $ hg evolve
  update:[0] c_A
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  working directory is now at 9f0188af4c58
  $ hg glog
  @  0:9f0188af4c58 (draft): c_A
  

C. Obsolete wdp with multiple successor (divergence rewriting)
---------------------------------------------------------------

  $ hg metaedit -r 'desc(u_B)' -d '0 1' --hidden
  $ hg metaedit -r 'desc(c_B)' -d '0 1' --hidden
  2 new content-divergent changesets
  $ hg up -r 'min(desc(c_B))' --hidden
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 707ee88b2870
  (hidden revision '707ee88b2870' has diverged)
  working directory parent is obsolete! (707ee88b2870)
  (707ee88b2870 has diverged, use 'hg evolve --list --content-divergent' to resolve the issue)

  $ hg evolve
  parent is obsolete with multiple successors:
  [3] u_B
  [4] c_B
  [2]

  $ hg glog
  *  4:39e54eb7aa3c (draft): c_B [content-divergent]
  |
  | *  3:90624b574289 (draft): u_B [content-divergent]
  |/
  | @  1:707ee88b2870 (draft): c_B
  |/
  o  0:9f0188af4c58 (draft): c_A
  

D. Obsolete wdp with multiple successor (split rewriting)
----------------------------------------------------------

#TODO: yet to write tests for this case