Patchwork [1,of,2,V2] split: new extension to split changesets

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Submitter Jun Wu
Date June 25, 2017, 6:08 a.m.
Message ID <0a25f04006ce0e4d5088.1498370880@x1c>
Download mbox | patch
Permalink /patch/21697/
State Changes Requested
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Jun Wu - June 25, 2017, 6:08 a.m.
# HG changeset patch
# User Jun Wu <quark@fb.com>
# Date 1498370621 25200
#      Sat Jun 24 23:03:41 2017 -0700
# Node ID 0a25f04006ce0e4d50881fe6a053e1cbc18882ef
# Parent  bec821f3bb744a7d13e33436433005654a263bc3
# Available At https://bitbucket.org/quark-zju/hg-draft
#              hg pull https://bitbucket.org/quark-zju/hg-draft -r 0a25f04006ce
split: new extension to split changesets

This diff introduces an experimental split extension to split changesets.

The implementation is largely inspired by Laurent Charignon's implementation
for mutable-history (changeset 9603aa1ecdfd54b0d86e262318a72e0a2ffeb6cc [1])

This version contains various improvements:

  - Rebase by default
    This is more friendly for new users. Split won't lead to merge conflicts
    so a rebase won't give the user more trouble.
    This has been on by default at Facebook for months now and seems to be a
    good UX improvement.

  - Remove "Done split? [y/n]" prompt
    That could be detected by checking repo.status() instead.

  - Works with obsstore disabled
    Without obsstore, split uses strip to clean up old nodes, and it can
    even handle split a non-head changeset with "allowunstable" disabled,
    since it runs a rebase to solve the "unstable" issue in a same
    transaction.

[1]: https://bitbucket.org/marmoute/mutable-history/commits/9603aa1ecdfd54b

Patch

diff --git a/hgext/split.py b/hgext/split.py
new file mode 100644
--- /dev/null
+++ b/hgext/split.py
@@ -0,0 +1,182 @@ 
+# split.py - split a changeset into smaller ones
+#
+# Copyright 2015 Laurent Charignon <lcharignon@fb.com>
+# Copyright 2017 Facebook, Inc.
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License version 2 or any later version.
+"""command to split a changeset into smaller ones (EXPERIMENTAL)"""
+
+from __future__ import absolute_import
+
+from mercurial.i18n import _
+
+from mercurial import (
+    bookmarks,
+    cmdutil,
+    commands,
+    error,
+    extensions,
+    hg,
+    node,
+    obsolete,
+    registrar,
+    repair,
+    revsetlang,
+    scmutil,
+)
+
+cmdtable = {}
+command = registrar.command(cmdtable)
+
+# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
+# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
+# be specifying the version(s) of Mercurial they are tested with, or
+# leave the attribute unspecified.
+testedwith = 'ships-with-hg-core'
+
+@command('^split',
+    [('r', 'rev', '', _("revision to split"), _('REV')),
+     ('', 'no-rebase', False, _('do not rebase descendants after split')),
+    ] + cmdutil.commitopts2,
+    _('hg split [[-r] REV] [--no-rebase]'))
+def split(ui, repo, *args, **opts):
+    """split a changeset into smaller ones
+
+    Repetitively prompt changes and commit message for new changesets until
+    there is nothing left in the original changeset.
+
+    If --rev was not given, split the working directory parent.
+
+    If --no-rebase was not set, rebase old descendants on top of the last new
+    changeset.
+    """
+    revlist = []
+    if opts.get('rev'):
+        revlist.append(opts.get('rev'))
+    revlist.extend(args)
+    revs = scmutil.revrange(repo, revlist or ['.'])
+    if len(revs) > 1:
+        raise error.Abort(_('cannot split multiple revisions'))
+
+    rev = revs.first()
+    ctx = repo[rev]
+    if rev is None or ctx.node() == node.nullid:
+        ui.status(_('nothing to split\n'))
+        return 1
+    if ctx.node() is None:
+        raise error.Abort(_('cannot split working directory'))
+
+    descendants = repo.revs('(%d::) - (%d)', ctx, ctx)
+    if opts.get('no_rebase'):
+        allowunstable = obsolete.isenabled(repo, obsolete.allowunstableopt)
+        if not allowunstable and descendants:
+            raise error.Abort(
+                _('cannot split changeset with children without rebase'))
+        torebase = ()
+    else:
+        if descendants:
+            try:
+                extensions.find('rebase').rebase
+            except (KeyError, AttributeError):
+                raise error.Abort(_('rebase extension is required'))
+        torebase = descendants
+
+    if len(ctx.parents()) > 1:
+        raise error.Abort(_('cannot split a merge changeset'))
+
+    cmdutil.bailifchanged(repo, merge=False)
+
+    # Deactivate bookmark temporarily so it won't get moved unintentionally
+    bname = repo._activebookmark
+    if bname and repo._bookmarks[bname] != ctx.node():
+        bookmarks.deactivate(repo)
+
+    with repo.wlock():
+        with repo.lock():
+            # Not using transaction with block because "dorebase" may want to
+            # close the transaction earlier.
+            # NOTE: strip might be made smarter to "work" in a transaction.
+            tr = repo.transaction('split')
+            try:
+                wnode = repo['.'].node()
+                top = None
+                try:
+                    top = dosplit(ui, repo, tr, ctx, opts)
+                finally:
+                    # top is None: split failed, need update --clean recovery.
+                    # wnode == ctx.node(): wnode split, no need to update.
+                    if top is None or wnode != ctx.node():
+                        hg.clean(repo, wnode, show_stats=False)
+                    if bname:
+                        bookmarks.activate(repo, bname)
+                if torebase and top:
+                    dorebase(ui, repo, torebase, top)
+                if top:
+                    dostrip(ui, repo, ctx.node())
+            finally:
+                tr = repo.currenttransaction()
+                if tr:
+                    tr.close()
+
+def dosplit(ui, repo, tr, ctx, opts):
+    committed = [] # [ctx]
+
+    # Set working parent to ctx.p1(), and keep working copy as ctx's content
+    # NOTE: if we can have "update without touching working copy" API, the
+    # revert step could be cheaper.
+    hg.clean(repo, ctx.p1().node(), show_stats=False)
+    parents = repo.changelog.parents(ctx.node())
+    ui.pushbuffer()
+    cmdutil.revert(ui, repo, ctx, parents)
+    ui.popbuffer() # discard "reverting ..." messages
+
+    # Any modified, added, removed, deleted result means split is incomplete
+    incomplete = lambda repo: any(repo.status()[:4])
+
+    # Main split loop
+    while incomplete(repo):
+        opts.update({
+            'edit': True,
+            'interactive': True,
+            'message': ctx.description(),
+        })
+        commands.commit(ui, repo, **opts)
+        newctx = repo['.']
+        committed.append(newctx)
+
+    if not committed:
+        raise error.Abort(_('cannot split an empty revision'))
+
+    # Move bookmarks
+    oldbookmarks = repo.nodebookmarks(ctx.node())
+    if oldbookmarks and committed:
+        marks = repo._bookmarks
+        newnode = committed[-1].node()
+        for name in oldbookmarks:
+            marks[name] = newnode
+        marks.recordchange(tr)
+
+    # Write obsmarkers
+    if obsolete.isenabled(repo, obsolete.createmarkersopt):
+        obsolete.createmarkers(repo, [(ctx, committed)], operation='split')
+
+    return committed[-1]
+
+def dorebase(ui, repo, src, dest):
+    tr = repo.currenttransaction()
+    if not obsolete.isenabled(repo, obsolete.createmarkersopt) and tr:
+        # rebase calls strip, which cannot be inside a transaction
+        tr.close()
+    rebase = extensions.find('rebase')
+    rebase.rebase(ui, repo, rev=[revsetlang.formatspec('%ld', src)],
+                  dest=revsetlang.formatspec('%d', dest))
+
+def dostrip(ui, repo, node):
+    if obsolete.isenabled(repo, obsolete.createmarkersopt):
+        # obsmarker written by dosplit will hide node
+        return
+    tr = repo.currenttransaction()
+    if tr:
+        tr.close()
+    repair.strip(ui, repo, [node])
diff --git a/tests/test-split.t b/tests/test-split.t
new file mode 100644
--- /dev/null
+++ b/tests/test-split.t
@@ -0,0 +1,415 @@ 
+#testcases default obsstore
+
+  $ cat > $TESTTMP/editor.py <<EOF
+  > #!$PYTHON
+  > import os, sys
+  > path = os.path.join(os.environ['TESTTMP'], 'messages')
+  > messages = open(path).read().split('--\n')
+  > prompt = open(sys.argv[1]).read()
+  > sys.stdout.write(''.join('EDITOR: %s' % l for l in prompt.splitlines(True)))
+  > sys.stdout.flush()
+  > with open(sys.argv[1], 'w') as f:
+  >    f.write(messages[0])
+  > with open(path, 'w') as f:
+  >    f.write('--\n'.join(messages[1:]))
+  > EOF
+
+  $ cat >> $HGRCPATH <<EOF
+  > [extensions]
+  > split=
+  > [ui]
+  > interactive=1
+  > [diff]
+  > git=1
+  > unified=0
+  > [alias]
+  > glog=log -G -T '{rev}:{node|short} {desc} {bookmarks}\n'
+  > EOF
+
+#if obsstore
+  $ cat >> $HGRCPATH <<EOF
+  > [experimental]
+  > evolution=all
+  > EOF
+#endif
+
+  $ hg init a
+  $ cd a
+
+Nothing to split
+
+  $ hg split
+  nothing to split
+  [1]
+
+  $ hg commit -m empty --config ui.allowemptycommit=1
+  $ hg split
+  abort: cannot split an empty revision
+  [255]
+
+  $ rm -rf .hg
+  $ hg init
+
+Cannot split working directory
+
+  $ hg split -r 'wdir()'
+  abort: cannot split working directory
+  [255]
+
+Split a head
+
+  $ $TESTDIR/seq.py 1 5 >> a
+  $ hg ci -m a1 -A a -q
+  $ hg bookmark -i r1
+  $ sed 's/1/11/;s/3/33/;s/5/55/' a > b
+  $ mv b a
+  $ hg ci -m a2 -q
+  $ hg bookmark -i r2
+
+  $ cp -R . ../b
+  $ cp -R . ../c
+
+  $ hg bookmark r3
+
+  $ hg split 'all()'
+  abort: cannot split multiple revisions
+  [255]
+
+  $ runsplit() {
+  > cat > $TESTTMP/messages <<EOF
+  > split 1
+  > --
+  > split 2
+  > --
+  > split 3
+  > EOF
+  > cat <<EOF | hg split "$@"
+  > y
+  > y
+  > y
+  > y
+  > y
+  > y
+  > EOF
+  > }
+
+  $ HGEDITOR=false runsplit
+  diff --git a/a b/a
+  1 hunks, 1 lines changed
+  examine changes to 'a'? [Ynesfdaq?] y
+  
+  @@ -5,1 +5,1 @@ 4
+  -5
+  +55
+  record this change to 'a'? [Ynesfdaq?] y
+  
+  abort: edit failed: false exited with status 1
+  [255]
+  $ hg status
+
+  $ HGEDITOR="$PYTHON $TESTTMP/editor.py"
+  $ runsplit
+  diff --git a/a b/a
+  1 hunks, 1 lines changed
+  examine changes to 'a'? [Ynesfdaq?] y
+  
+  @@ -5,1 +5,1 @@ 4
+  -5
+  +55
+  record this change to 'a'? [Ynesfdaq?] y
+  
+  EDITOR: a2
+  EDITOR: 
+  EDITOR: 
+  EDITOR: HG: Enter commit message.  Lines beginning with 'HG:' are removed.
+  EDITOR: HG: Leave message empty to abort commit.
+  EDITOR: HG: --
+  EDITOR: HG: user: test
+  EDITOR: HG: branch 'default'
+  EDITOR: HG: changed a
+  created new head
+  diff --git a/a b/a
+  1 hunks, 1 lines changed
+  examine changes to 'a'? [Ynesfdaq?] y
+  
+  @@ -3,1 +3,1 @@ 2
+  -3
+  +33
+  record this change to 'a'? [Ynesfdaq?] y
+  
+  EDITOR: a2
+  EDITOR: 
+  EDITOR: 
+  EDITOR: HG: Enter commit message.  Lines beginning with 'HG:' are removed.
+  EDITOR: HG: Leave message empty to abort commit.
+  EDITOR: HG: --
+  EDITOR: HG: user: test
+  EDITOR: HG: branch 'default'
+  EDITOR: HG: changed a
+  diff --git a/a b/a
+  1 hunks, 1 lines changed
+  examine changes to 'a'? [Ynesfdaq?] y
+  
+  @@ -1,1 +1,1 @@
+  -1
+  +11
+  record this change to 'a'? [Ynesfdaq?] y
+  
+  EDITOR: a2
+  EDITOR: 
+  EDITOR: 
+  EDITOR: HG: Enter commit message.  Lines beginning with 'HG:' are removed.
+  EDITOR: HG: Leave message empty to abort commit.
+  EDITOR: HG: --
+  EDITOR: HG: user: test
+  EDITOR: HG: branch 'default'
+  EDITOR: HG: changed a
+  saved backup bundle to $TESTTMP/a/.hg/strip-backup/1df0d5c5a3ab-8341b760-backup.hg (glob) (?)
+
+#if default
+  $ hg bookmark
+     r1                        0:a61bcde8c529
+     r2                        3:00eebaf8d2e2
+   * r3                        3:00eebaf8d2e2
+  $ hg glog -p
+  @  3:00eebaf8d2e2 split 3 r2 r3
+  |  diff --git a/a b/a
+  |  --- a/a
+  |  +++ b/a
+  |  @@ -1,1 +1,1 @@
+  |  -1
+  |  +11
+  |
+  o  2:a09ad58faae3 split 2
+  |  diff --git a/a b/a
+  |  --- a/a
+  |  +++ b/a
+  |  @@ -3,1 +3,1 @@
+  |  -3
+  |  +33
+  |
+  o  1:e704349bd21b split 1
+  |  diff --git a/a b/a
+  |  --- a/a
+  |  +++ b/a
+  |  @@ -5,1 +5,1 @@
+  |  -5
+  |  +55
+  |
+  o  0:a61bcde8c529 a1 r1
+     diff --git a/a b/a
+     new file mode 100644
+     --- /dev/null
+     +++ b/a
+     @@ -0,0 +1,5 @@
+     +1
+     +2
+     +3
+     +4
+     +5
+  
+#endif
+#if obsstore
+  $ hg bookmark
+     r1                        0:a61bcde8c529
+     r2                        4:00eebaf8d2e2
+   * r3                        4:00eebaf8d2e2
+  $ hg glog
+  @  4:00eebaf8d2e2 split 3 r2 r3
+  |
+  o  3:a09ad58faae3 split 2
+  |
+  o  2:e704349bd21b split 1
+  |
+  o  0:a61bcde8c529 a1 r1
+  
+#endif
+
+Split a head while working parent is not that head
+
+  $ cd $TESTTMP/b
+
+  $ hg up 0 -q
+  $ hg bookmark r3
+
+  $ runsplit tip >/dev/null
+
+#if default
+  $ hg bookmark
+     r1                        0:a61bcde8c529
+     r2                        3:00eebaf8d2e2
+   * r3                        0:a61bcde8c529
+  $ hg glog
+  o  3:00eebaf8d2e2 split 3 r2
+  |
+  o  2:a09ad58faae3 split 2
+  |
+  o  1:e704349bd21b split 1
+  |
+  @  0:a61bcde8c529 a1 r1 r3
+  
+#endif
+#if obsstore
+  $ hg bookmark
+     r1                        0:a61bcde8c529
+     r2                        4:00eebaf8d2e2
+   * r3                        0:a61bcde8c529
+  $ hg glog
+  o  4:00eebaf8d2e2 split 3 r2
+  |
+  o  3:a09ad58faae3 split 2
+  |
+  o  2:e704349bd21b split 1
+  |
+  @  0:a61bcde8c529 a1 r1 r3
+  
+#endif
+
+Split a non-head
+
+  $ cd $TESTTMP/c
+  $ echo d > d
+  $ hg ci -m d1 -A d
+  $ hg bookmark -i d1
+  $ echo 2 >> d
+  $ hg ci -m d2
+  $ echo 3 >> d
+  $ hg ci -m d3
+  $ hg bookmark -i d3
+  $ hg up '.^' -q
+  $ hg bookmark d2
+  $ cp -R . ../d
+
+  $ runsplit 1
+  abort: rebase extension is required
+  [255]
+  $ runsplit -r 1 --config extensions.rebase= | grep rebasing
+  rebasing 2:b5c5ea414030 "d1" (d1)
+  rebasing 3:f4a0a8d004cc "d2" (d2)
+  rebasing 4:777940761eba "d3" (d3)
+#if default
+  $ hg bookmark
+     d1                        4:c4b449ef030e
+   * d2                        5:c9dd00ab36a3
+     d3                        6:19f476bc865c
+     r1                        0:a61bcde8c529
+     r2                        3:00eebaf8d2e2
+  $ hg glog -p
+  o  6:19f476bc865c d3 d3
+  |  diff --git a/d b/d
+  |  --- a/d
+  |  +++ b/d
+  |  @@ -2,0 +3,1 @@
+  |  +3
+  |
+  @  5:c9dd00ab36a3 d2 d2
+  |  diff --git a/d b/d
+  |  --- a/d
+  |  +++ b/d
+  |  @@ -1,0 +2,1 @@
+  |  +2
+  |
+  o  4:c4b449ef030e d1 d1
+  |  diff --git a/d b/d
+  |  new file mode 100644
+  |  --- /dev/null
+  |  +++ b/d
+  |  @@ -0,0 +1,1 @@
+  |  +d
+  |
+  o  3:00eebaf8d2e2 split 3 r2
+  |  diff --git a/a b/a
+  |  --- a/a
+  |  +++ b/a
+  |  @@ -1,1 +1,1 @@
+  |  -1
+  |  +11
+  |
+  o  2:a09ad58faae3 split 2
+  |  diff --git a/a b/a
+  |  --- a/a
+  |  +++ b/a
+  |  @@ -3,1 +3,1 @@
+  |  -3
+  |  +33
+  |
+  o  1:e704349bd21b split 1
+  |  diff --git a/a b/a
+  |  --- a/a
+  |  +++ b/a
+  |  @@ -5,1 +5,1 @@
+  |  -5
+  |  +55
+  |
+  o  0:a61bcde8c529 a1 r1
+     diff --git a/a b/a
+     new file mode 100644
+     --- /dev/null
+     +++ b/a
+     @@ -0,0 +1,5 @@
+     +1
+     +2
+     +3
+     +4
+     +5
+  
+#endif
+#if obsstore
+  $ hg bookmark
+     d1                        8:c4b449ef030e
+   * d2                        9:c9dd00ab36a3
+     d3                        10:19f476bc865c
+     r1                        0:a61bcde8c529
+     r2                        7:00eebaf8d2e2
+  $ hg glog
+  o  10:19f476bc865c d3 d3
+  |
+  @  9:c9dd00ab36a3 d2 d2
+  |
+  o  8:c4b449ef030e d1 d1
+  |
+  o  7:00eebaf8d2e2 split 3 r2
+  |
+  o  6:a09ad58faae3 split 2
+  |
+  o  5:e704349bd21b split 1
+  |
+  o  0:a61bcde8c529 a1 r1
+  
+#endif
+
+Split a non-head without rebase
+
+  $ cd $TESTTMP/d
+#if default
+  $ runsplit -r 1 --no-rebase
+  abort: cannot split changeset with children without rebase
+  [255]
+#endif
+#if obsstore
+  $ runsplit -r 1 --no-rebase >/dev/null
+  $ hg bookmark
+     d1                        2:b5c5ea414030
+   * d2                        3:f4a0a8d004cc
+     d3                        4:777940761eba
+     r1                        0:a61bcde8c529
+     r2                        7:00eebaf8d2e2
+
+  $ hg glog
+  o  7:00eebaf8d2e2 split 3 r2
+  |
+  o  6:a09ad58faae3 split 2
+  |
+  o  5:e704349bd21b split 1
+  |
+  | o  4:777940761eba d3 d3
+  | |
+  | @  3:f4a0a8d004cc d2 d2
+  | |
+  | o  2:b5c5ea414030 d1 d1
+  | |
+  | x  1:1df0d5c5a3ab a2
+  |/
+  o  0:a61bcde8c529 a1 r1
+  
+#endif