[PATCH STABLE V3] rebase: move bookmark to destination for commits becoming empty (issue5627)
Martin von Zweigbergk
martinvonz at google.com
Wed Jul 26 14:23:33 EDT 2017
On Tue, Jul 25, 2017 at 12:08 AM, Jun Wu <quark at fb.com> wrote:
> # HG changeset patch
> # User Jun Wu <quark at fb.com>
> # Date 1500965576 25200
> # Mon Jul 24 23:52:56 2017 -0700
> # Branch stable
> # Node ID 1f0a72adb6f8dffe6edd24b3147c590aada3a5b6
> # Parent e12c3049af8ee85dfcf0575297fd568dde5cc8d2
> # Available At https://bitbucket.org/quark-zju/hg-draft
> # hg pull https://bitbucket.org/quark-zju/hg-draft -r 1f0a72adb6f8
> rebase: move bookmark to destination for commits becoming empty (issue5627)
>
> When rebasing a changeset X and that changeset becomes empty, we should move
> the bookmark on X to rebase destination.
>
> This is a regression caused by the scmutil.cleanupnodes refactoring for
> rebase.
>
> The `adjustdest` function calculates the destination of bookmark movement.
> It was back-ported from https://phab.mercurial-scm.org/D21. It might be
> slightly more powerful than the minimal requirement to solve this issue.
> For example, it's impossible for a merge changeset to become empty while any
> of its ancestors does not become empty, but the code could handle that case.
IIUC, that will be true even with D21. So you're saying that it just
happens to handle that hypothetical situation, not that that it was
needed for D21 and you didn't bother removing that feature while
back-porting it, right?
But do note (as you probably already have) that the current rebase
code (pre-D21) will behave differently between p1 and p2 in this case:
$ hg debugdrawdag<<'EOS'
> E
> /|
> B C D
> \|/
> A
> EOS
$ hg co E
$ hg revert -r D -a
$ hg ci --amend -m E
$ hg debugdrawdag<<'EOS'
> H
> |
> C
> |
> B
> EOS
$ hg rebase -r '(A::)-(B::)-A' -d H
$ hg log -G -T '{rev} {desc} {bookmarks}'
@ 5 E
|\
| o 4 D
|/
o 3 H
|
o 2 C
|
o 1 B
|
o 0 A
If you instead revert E's contents to C and up D in the upstream, you
will not get the merge commit E after rebase. I'm not sure which is
better, but they should clearly not be different.
> Since the code is reasonably short and clean, and helps the upcoming D21
> series, I'd like to check-in `adjustdest` now.
Yay for any piece of D21 that can be factored out :-)
>
> Thanks Martin von Zweigbergk for spotting corner cases (-k and descendant
> with bookmarks) in this area!
>
> diff --git a/hgext/rebase.py b/hgext/rebase.py
> --- a/hgext/rebase.py
> +++ b/hgext/rebase.py
> @@ -513,5 +513,6 @@ class rebaseruntime(object):
> if self.collapsef:
> collapsedas = newnode
> - clearrebased(ui, repo, self.state, self.skipped, collapsedas)
> + clearrebased(ui, repo, self.dest, self.state, self.skipped,
> + collapsedas)
>
> clearstatus(repo)
> @@ -898,4 +899,56 @@ def rebasenode(repo, rev, p1, base, stat
> return stats
>
> +def adjustdest(repo, rev, dest, state):
> + """adjust rebase destination given the current rebase state
> +
> + rev is what being rebased. Return a list of two revs, which are the
I'm adding the missing "rev is what *is* being" here.
> + adjusted destinations for rev's p1 and p2, respectively. If a parent is
> + nullrev, return dest without adjustment for it.
> +
> + For example, when doing rebase -r B+E -d F, rebase will first move B to B1,
> + and E's destination will be adjusted from F to B1.
> +
> + B1 <- written during rebasing B
> + |
> + F <- original destination of B, E
> + |
> + | E <- rev, which is being rebased
> + | |
> + | D <- prev, one parent of rev being checked
> + | |
> + | x <- skipped, ex. no successor or successor in (::dest)
> + | |
> + | C
> + | |
> + | B <- rebased as B1
> + |/
> + A
> +
> + Another example about merge changeset, rebase -r C+G+H -d K, rebase will
> + first move C to C1, G to G1, and when it's checking H, the adjusted
> + destinations will be [C1, G1].
> +
> + H C1 G1
> + /| | /
> + F G |/
> + K | | -> K
> + | C D |
> + | |/ |
> + | B | ...
> + |/ |/
> + A A
> + """
> + result = []
> + for prev in repo.changelog.parentrevs(rev):
> + adjusted = dest
> + if prev != nullrev:
> + # pick already rebased revs from state
> + source = [s for s, d in state.items() if d > 0]
Looks like this can be moved outside of the loop?
> + candidate = repo.revs('max(%ld and (::%d))', source, prev).first()
> + if candidate is not None:
> + adjusted = state[candidate]
> + result.append(adjusted)
> + return result
> +
> def nearestrebased(repo, rev, state):
> """return the nearest ancestors of rev in the rebase result"""
> @@ -1302,5 +1355,5 @@ def buildstate(repo, dest, rebaseset, co
> return originalwd, dest.rev(), state
>
> -def clearrebased(ui, repo, state, skipped, collapsedas=None):
> +def clearrebased(ui, repo, dest, state, skipped, collapsedas=None):
> """dispose of rebased revision at the end of the rebase
>
> @@ -1308,4 +1361,13 @@ def clearrebased(ui, repo, state, skippe
> `collapsedas` node."""
> tonode = repo.changelog.node
> + # Move bookmark of skipped nodes to destination. This cannot be handled
> + # by scmutil.cleanupnodes since it will treat rev as removed (no successor)
> + # and move bookmark backwards.
> + bmchanges = [(name, tonode(max(adjustdest(repo, rev, dest, state))))
> + for rev in skipped
> + for name in repo.nodebookmarks(tonode(rev))]
> + if bmchanges:
> + with repo.transaction('rebase') as tr:
> + repo._bookmarks.applychanges(repo, tr, bmchanges)
> mapping = {}
> for rev, newrev in sorted(state.items()):
> diff --git a/tests/test-rebase-emptycommit.t b/tests/test-rebase-emptycommit.t
> new file mode 100644
> --- /dev/null
> +++ b/tests/test-rebase-emptycommit.t
> @@ -0,0 +1,202 @@
> + $ cat >> $HGRCPATH<<EOF
> + > [extensions]
> + > rebase=
> + > drawdag=$TESTDIR/drawdag.py
> + > EOF
> +
> + $ hg init non-merge
> + $ cd non-merge
> + $ hg debugdrawdag<<'EOS'
> + > F
> + > |
> + > E
> + > |
> + > D
> + > |
> + > B C
> + > |/
> + > A
> + > EOS
> +
> + $ for i in C D E F; do
> + > hg bookmark -r $i -i BOOK-$i
> + > done
> +
> + $ hg debugdrawdag<<'EOS'
> + > E
> + > |
> + > D
> + > |
> + > B
> + > EOS
> +
> + $ hg log -G -T '{rev} {desc} {bookmarks}'
> + o 7 E
> + |
> + o 6 D
> + |
> + | o 5 F BOOK-F
> + | |
> + | o 4 E BOOK-E
> + | |
> + | o 3 D BOOK-D
> + | |
> + | o 2 C BOOK-C
> + | |
> + o | 1 B
> + |/
> + o 0 A
> +
> +With --keep, bookmark should not move
> +
> + $ hg rebase -r 3+4 -d E --keep
> + rebasing 3:e7b3f00ed42e "D" (BOOK-D)
> + note: rebase of 3:e7b3f00ed42e created no changes to commit
> + rebasing 4:69a34c08022a "E" (BOOK-E)
> + note: rebase of 4:69a34c08022a created no changes to commit
> + $ hg log -G -T '{rev} {desc} {bookmarks}'
> + o 7 E
> + |
> + o 6 D
> + |
> + | o 5 F BOOK-F
> + | |
> + | o 4 E BOOK-E
> + | |
> + | o 3 D BOOK-D
> + | |
> + | o 2 C BOOK-C
> + | |
> + o | 1 B
> + |/
> + o 0 A
> +
> +Bookmark is usually an indication of a head. For changes are introduced by
I'm changing this to "changes *that* are" in flight.
> +an ancestor of bookmark B, after moving B to B-NEW, the changes are ideally
> +still introduced by an ancestor of changeset on B-NEW. In the below case,
> +"BOOK-D", and "BOOK-E" include changes introduced by "C".
> +
> + $ hg rebase -s 2 -d E
> + rebasing 2:dc0947a82db8 "C" (C BOOK-C)
> + rebasing 3:e7b3f00ed42e "D" (BOOK-D)
> + note: rebase of 3:e7b3f00ed42e created no changes to commit
> + rebasing 4:69a34c08022a "E" (BOOK-E)
> + note: rebase of 4:69a34c08022a created no changes to commit
> + rebasing 5:6b2aeab91270 "F" (F BOOK-F)
> + saved backup bundle to $TESTTMP/non-merge/.hg/strip-backup/dc0947a82db8-52bb4973-rebase.hg (glob)
> + $ hg log -G -T '{rev} {desc} {bookmarks}'
> + o 5 F BOOK-F
> + |
> + o 4 C BOOK-C BOOK-D BOOK-E
> + |
> + o 3 E
> + |
> + o 2 D
> + |
> + o 1 B
> + |
> + o 0 A
> +
> +Merge and its ancestors all become empty
> +
> + $ hg init $TESTTMP/merge1
> + $ cd $TESTTMP/merge1
> +
> + $ hg debugdrawdag<<'EOS'
> + > E
> + > /|
> + > B C D
> + > \|/
> + > A
> + > EOS
> +
> + $ for i in C D E; do
> + > hg bookmark -r $i -i BOOK-$i
> + > done
> +
> + $ hg debugdrawdag<<'EOS'
> + > H
> + > |
> + > D
> + > |
> + > C
> + > |
> + > B
> + > EOS
> +
> + $ hg rebase -r '(A::)-(B::)-A' -d H
nit: The revisions to rebase can be described more simply as '(::E)-A'
(or e.g. 'only(E,A)' or 'only(E,H)' if you prefer).
> + rebasing 2:dc0947a82db8 "C" (BOOK-C)
> + note: rebase of 2:dc0947a82db8 created no changes to commit
> + rebasing 3:b18e25de2cf5 "D" (BOOK-D)
> + note: rebase of 3:b18e25de2cf5 created no changes to commit
> + rebasing 4:86a1f6686812 "E" (E BOOK-E)
> + note: rebase of 4:86a1f6686812 created no changes to commit
> + saved backup bundle to $TESTTMP/merge1/.hg/strip-backup/b18e25de2cf5-1fd0a4ba-rebase.hg (glob)
> +
> + $ hg log -G -T '{rev} {desc} {bookmarks}'
> + o 4 H BOOK-C BOOK-D BOOK-E
> + |
> + o 3 D
> + |
> + o 2 C
> + |
> + o 1 B
> + |
> + o 0 A
> +
> +Part of ancestors of a merge become empty
> +
> + $ hg init $TESTTMP/merge2
> + $ cd $TESTTMP/merge2
> +
> + $ hg debugdrawdag<<'EOS'
> + > G
> + > /|
> + > E F
> + > | |
> + > B C D
> + > \|/
> + > A
> + > EOS
> +
> + $ for i in C D E F G; do
> + > hg bookmark -r $i -i BOOK-$i
> + > done
> +
> + $ hg debugdrawdag<<'EOS'
> + > H
> + > |
> + > F
> + > |
> + > C
> + > |
> + > B
> + > EOS
> +
> + $ hg rebase -r '(A::)-(B::)-A' -d H
> + rebasing 2:dc0947a82db8 "C" (BOOK-C)
> + note: rebase of 2:dc0947a82db8 created no changes to commit
> + rebasing 3:b18e25de2cf5 "D" (D BOOK-D)
> + rebasing 4:03ca77807e91 "E" (E BOOK-E)
> + rebasing 5:ad6717a6a58e "F" (BOOK-F)
> + note: rebase of 5:ad6717a6a58e created no changes to commit
> + rebasing 6:c58e8bdac1f4 "G" (G BOOK-G)
> + saved backup bundle to $TESTTMP/merge2/.hg/strip-backup/b18e25de2cf5-2d487005-rebase.hg (glob)
> +
> + $ hg log -G -T '{rev} {desc} {bookmarks}'
> + o 7 G BOOK-G
> + |\
> + | o 6 E BOOK-E
> + | |
> + o | 5 D BOOK-D BOOK-F
> + |/
> + o 4 H BOOK-C
> + |
> + o 3 F
> + |
> + o 2 C
> + |
> + o 1 B
> + |
> + o 0 A
> +
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