view tests/test-rebase-interruptions.t @ 39764:e4e881572382

localrepo: iteratively derive local repository type

This commit implements the dynamic local repository type derivation
that was explained in the recent commit
bfeab472e3c0 "localrepo: create new function for instantiating a local
repo object."

Instead of a static localrepository class/type which must be customized
after construction, we now dynamically construct a type by building up
base classes/types to represent specific repository interfaces.

Conceptually, the end state is similar to what was happening when
various extensions would monkeypatch the __class__ of newly-constructed
repo instances. However, the approach is inverted. Instead of making
the instance then customizing it, we do the customization up front
by influencing the behavior of the type then we instantiate that
custom type.

This approach gives us much more flexibility. For example, we can
use completely separate classes for implementing different aspects
of the repository. For example, we could have one class representing
revlog-based file storage and another representing non-revlog based
file storage. When then choose which implementation to use based on
the presence of repo requirements.

A concern with this approach is that it creates a lot more types
and complexity and that complexity adds overhead. Yes, it is true that
this approach will result in more types being created. Yes, this is
more complicated than traditional "instantiate a static type." However,
I believe the alternatives to supporting alternate storage backends
are just as complicated. (Before I arrived at this solution, I had
patches storing factory functions on local repo instances for e.g.
constructing a file storage instance. We ended up having a handful
of these. And this was logically identical to assigning custom
methods. Since we were logically changing the type of the instance,
I figured it would be better to just use specialized types instead
of introducing levels of abstraction at run-time.)

On the performance front, I don't believe that having N base classes
has any significant performance overhead compared to just a single base
class. Intuition says that Python will need to iterate the base classes
to find an attribute. However, CPython caches method lookups: as long as
the __class__ or MRO isn't changing, method attribute lookup should be
constant time after first access. And non-method attributes are stored
in __dict__, of which there is only 1 per object, so the number of
base classes for __dict__ is irrelevant.

Anyway, this commit splits up the monolithic completelocalrepository
interface into sub-interfaces: 1 for file storage and 1 representing
everything else.

We've taught ``makelocalrepository()`` to call a series of factory
functions which will produce types implementing specific interfaces.
It then calls type() to create a new type from the built-up list of
base types.

This commit should be considered a start and not the end state. I
suspect we'll hit a number of problems as we start to implement
alternate storage backends:

* Passing custom arguments to __init__ and setting custom attributes
  on __dict__.
* Customizing the set of interfaces that are needed. e.g. the
  "readonly" intent could translate to not requesting an interface
  providing methods related to writing.
* More ergonomic way for extensions to insert themselves so their
  callbacks aren't unconditionally called.
* Wanting to modify vfs instances, other arguments passed to __init__.

That being said, this code is usable in its current state and I'm
convinced future commits will demonstrate the value in this approach.

Differential Revision: https://phab.mercurial-scm.org/D4642

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} '{desc}' {branches}\n"
  > tglogp = log -G --template "{rev}: {node|short} {phase} '{desc}' {branches}\n"
  > EOF


  $ hg init a
  $ cd a

  $ echo A > A
  $ hg ci -Am A
  adding A

  $ echo B > B
  $ hg ci -Am B
  adding B

  $ echo C >> A
  $ hg ci -m C

  $ hg up -q -C 0

  $ echo D >> A
  $ hg ci -m D
  created new head

  $ echo E > E
  $ hg ci -Am E
  adding E

  $ cd ..


Changes during an interruption - continue:

  $ hg clone -q -u . a a1
  $ cd a1

  $ hg tglog
  @  4: ae36e8e3dfd7 'E'
  |
  o  3: 46b37eabc604 'D'
  |
  | o  2: 965c486023db 'C'
  | |
  | o  1: 27547f69f254 'B'
  |/
  o  0: 4a2df7238c3b 'A'
  
Rebasing B onto E:

  $ hg rebase -s 1 -d 4
  rebasing 1:27547f69f254 "B"
  rebasing 2:965c486023db "C"
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Force a commit on C during the interruption:

  $ hg up -q -C 2 --config 'extensions.rebase=!'

  $ echo 'Extra' > Extra
  $ hg add Extra
  $ hg ci -m 'Extra' --config 'extensions.rebase=!'

Force this commit onto secret phase

  $ hg phase --force --secret 6

  $ hg tglogp
  @  6: deb5d2f93d8b secret 'Extra'
  |
  | o  5: 45396c49d53b draft 'B'
  | |
  | o  4: ae36e8e3dfd7 draft 'E'
  | |
  | o  3: 46b37eabc604 draft 'D'
  | |
  o |  2: 965c486023db draft 'C'
  | |
  o |  1: 27547f69f254 draft 'B'
  |/
  o  0: 4a2df7238c3b draft 'A'
  
Resume the rebasing:

  $ hg rebase --continue
  already rebased 1:27547f69f254 "B" as 45396c49d53b
  rebasing 2:965c486023db "C"
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Solve the conflict and go on:

  $ echo 'conflict solved' > A
  $ rm A.orig
  $ hg resolve -m A
  (no more unresolved files)
  continue: hg rebase --continue

  $ hg rebase --continue
  already rebased 1:27547f69f254 "B" as 45396c49d53b
  rebasing 2:965c486023db "C"
  warning: orphaned descendants detected, not stripping 27547f69f254, 965c486023db

  $ hg tglogp
  o  7: d2d25e26288e draft 'C'
  |
  | o  6: deb5d2f93d8b secret 'Extra'
  | |
  o |  5: 45396c49d53b draft 'B'
  | |
  @ |  4: ae36e8e3dfd7 draft 'E'
  | |
  o |  3: 46b37eabc604 draft 'D'
  | |
  | o  2: 965c486023db draft 'C'
  | |
  | o  1: 27547f69f254 draft 'B'
  |/
  o  0: 4a2df7238c3b draft 'A'
  
  $ cd ..


Changes during an interruption - abort:

  $ hg clone -q -u . a a2
  $ cd a2

  $ hg tglog
  @  4: ae36e8e3dfd7 'E'
  |
  o  3: 46b37eabc604 'D'
  |
  | o  2: 965c486023db 'C'
  | |
  | o  1: 27547f69f254 'B'
  |/
  o  0: 4a2df7238c3b 'A'
  
Rebasing B onto E:

  $ hg rebase -s 1 -d 4
  rebasing 1:27547f69f254 "B"
  rebasing 2:965c486023db "C"
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Force a commit on B' during the interruption:

  $ hg up -q -C 5 --config 'extensions.rebase=!'

  $ echo 'Extra' > Extra
  $ hg add Extra
  $ hg ci -m 'Extra' --config 'extensions.rebase=!'

  $ hg tglog
  @  6: 402ee3642b59 'Extra'
  |
  o  5: 45396c49d53b 'B'
  |
  o  4: ae36e8e3dfd7 'E'
  |
  o  3: 46b37eabc604 'D'
  |
  | o  2: 965c486023db 'C'
  | |
  | o  1: 27547f69f254 'B'
  |/
  o  0: 4a2df7238c3b 'A'
  
Abort the rebasing:

  $ hg rebase --abort
  warning: new changesets detected on destination branch, can't strip
  rebase aborted

  $ hg tglog
  @  6: 402ee3642b59 'Extra'
  |
  o  5: 45396c49d53b 'B'
  |
  o  4: ae36e8e3dfd7 'E'
  |
  o  3: 46b37eabc604 'D'
  |
  | o  2: 965c486023db 'C'
  | |
  | o  1: 27547f69f254 'B'
  |/
  o  0: 4a2df7238c3b 'A'
  
  $ cd ..

Changes during an interruption - abort (again):

  $ hg clone -q -u . a a3
  $ cd a3

  $ hg tglogp
  @  4: ae36e8e3dfd7 draft 'E'
  |
  o  3: 46b37eabc604 draft 'D'
  |
  | o  2: 965c486023db draft 'C'
  | |
  | o  1: 27547f69f254 draft 'B'
  |/
  o  0: 4a2df7238c3b draft 'A'
  
Rebasing B onto E:

  $ hg rebase -s 1 -d 4
  rebasing 1:27547f69f254 "B"
  rebasing 2:965c486023db "C"
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]

Change phase on B and B'

  $ hg up -q -C 5 --config 'extensions.rebase=!'
  $ hg phase --public 1
  $ hg phase --public 5
  $ hg phase --secret -f 2

  $ hg tglogp
  @  5: 45396c49d53b public 'B'
  |
  o  4: ae36e8e3dfd7 public 'E'
  |
  o  3: 46b37eabc604 public 'D'
  |
  | o  2: 965c486023db secret 'C'
  | |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
Abort the rebasing:

  $ hg rebase --abort
  warning: can't clean up public changesets 45396c49d53b
  rebase aborted

  $ hg tglogp
  @  5: 45396c49d53b public 'B'
  |
  o  4: ae36e8e3dfd7 public 'E'
  |
  o  3: 46b37eabc604 public 'D'
  |
  | o  2: 965c486023db secret 'C'
  | |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
Test rebase interrupted by hooks

  $ hg up 2
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo F > F
  $ hg add F
  $ hg ci -m F

  $ cd ..

(precommit version)

  $ cp -R a3 hook-precommit
  $ cd hook-precommit
  $ hg rebase --source 2 --dest 5 --tool internal:other --config 'hooks.precommit=hg status | grep "M A"'
  rebasing 2:965c486023db "C"
  M A
  rebasing 6:a0b2430ebfb8 "F" (tip)
  abort: precommit hook exited with status 1
  [255]
  $ hg tglogp
  @  7: 401ccec5e39f secret 'C'
  |
  | @  6: a0b2430ebfb8 secret 'F'
  | |
  o |  5: 45396c49d53b public 'B'
  | |
  o |  4: ae36e8e3dfd7 public 'E'
  | |
  o |  3: 46b37eabc604 public 'D'
  | |
  | o  2: 965c486023db secret 'C'
  | |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
  $ hg rebase --continue
  already rebased 2:965c486023db "C" as 401ccec5e39f
  rebasing 6:a0b2430ebfb8 "F"
  saved backup bundle to $TESTTMP/hook-precommit/.hg/strip-backup/965c486023db-aa6250e7-rebase.hg
  $ hg tglogp
  @  6: 6e92a149ac6b secret 'F'
  |
  o  5: 401ccec5e39f secret 'C'
  |
  o  4: 45396c49d53b public 'B'
  |
  o  3: ae36e8e3dfd7 public 'E'
  |
  o  2: 46b37eabc604 public 'D'
  |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
  $ cd ..

(pretxncommit version)

  $ cp -R a3 hook-pretxncommit
  $ cd hook-pretxncommit
  $ hg rebase --source 2 --dest 5 --tool internal:other \
  >     --config 'hooks.tonative.pretxncommit=True' --config 'hooks.pretxncommit=hg log -r $HG_NODE | grep "summary:     C"'
  rebasing 2:965c486023db "C"
  summary:     C
  rebasing 6:a0b2430ebfb8 "F" (tip)
  transaction abort!
  rollback completed
  abort: pretxncommit hook exited with status 1
  [255]
  $ hg tglogp
  @  7: 401ccec5e39f secret 'C'
  |
  | @  6: a0b2430ebfb8 secret 'F'
  | |
  o |  5: 45396c49d53b public 'B'
  | |
  o |  4: ae36e8e3dfd7 public 'E'
  | |
  o |  3: 46b37eabc604 public 'D'
  | |
  | o  2: 965c486023db secret 'C'
  | |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
  $ hg rebase --continue
  already rebased 2:965c486023db "C" as 401ccec5e39f
  rebasing 6:a0b2430ebfb8 "F"
  saved backup bundle to $TESTTMP/hook-pretxncommit/.hg/strip-backup/965c486023db-aa6250e7-rebase.hg
  $ hg tglogp
  @  6: 6e92a149ac6b secret 'F'
  |
  o  5: 401ccec5e39f secret 'C'
  |
  o  4: 45396c49d53b public 'B'
  |
  o  3: ae36e8e3dfd7 public 'E'
  |
  o  2: 46b37eabc604 public 'D'
  |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
  $ cd ..

(pretxnclose version)

  $ cp -R a3 hook-pretxnclose
  $ cd hook-pretxnclose
  $ hg rebase --source 2 --dest 5 --tool internal:other --config 'hooks.pretxnclose=hg log -r tip | grep "summary:     C"'
  rebasing 2:965c486023db "C"
  summary:     C
  rebasing 6:a0b2430ebfb8 "F" (tip)
  transaction abort!
  rollback completed
  abort: pretxnclose hook exited with status 1
  [255]
  $ hg tglogp
  @  7: 401ccec5e39f secret 'C'
  |
  | @  6: a0b2430ebfb8 secret 'F'
  | |
  o |  5: 45396c49d53b public 'B'
  | |
  o |  4: ae36e8e3dfd7 public 'E'
  | |
  o |  3: 46b37eabc604 public 'D'
  | |
  | o  2: 965c486023db secret 'C'
  | |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
  $ hg rebase --continue
  already rebased 2:965c486023db "C" as 401ccec5e39f
  rebasing 6:a0b2430ebfb8 "F"
  saved backup bundle to $TESTTMP/hook-pretxnclose/.hg/strip-backup/965c486023db-aa6250e7-rebase.hg
  $ hg tglogp
  @  6: 6e92a149ac6b secret 'F'
  |
  o  5: 401ccec5e39f secret 'C'
  |
  o  4: 45396c49d53b public 'B'
  |
  o  3: ae36e8e3dfd7 public 'E'
  |
  o  2: 46b37eabc604 public 'D'
  |
  | o  1: 27547f69f254 public 'B'
  |/
  o  0: 4a2df7238c3b public 'A'
  
  $ cd ..

Make sure merge state is cleaned up after a no-op rebase merge (issue5494)
  $ hg init repo
  $ cd repo
  $ echo a > a
  $ hg commit -qAm base
  $ echo b >> a
  $ hg commit -qm b
  $ hg up '.^'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo c >> a
  $ hg commit -qm c
  $ hg rebase -s 1 -d 2 --noninteractive
  rebasing 1:fdaca8533b86 "b"
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ echo a > a
  $ echo c >> a
  $ hg resolve --mark a
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue
  rebasing 1:fdaca8533b86 "b"
  note: rebase of 1:fdaca8533b86 created no changes to commit
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/fdaca8533b86-7fd70513-rebase.hg
  $ hg resolve --list
  $ test -d .hg/merge
  [1]
Now try again with --collapse
  $ hg unbundle -q .hg/strip-backup/fdaca8533b86-7fd70513-rebase.hg
  $ hg rebase -s 2 -d 1 --noninteractive --collapse
  rebasing 2:fdaca8533b86 "b" (tip)
  merging a
  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ echo a > a
  $ echo c >> a
  $ hg resolve --mark a
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase --continue
  rebasing 2:fdaca8533b86 "b" (tip)
  saved backup bundle to $TESTTMP/repo/.hg/strip-backup/fdaca8533b86-7fd70513-rebase.hg
  $ hg resolve --list
  $ test -d .hg/merge
  [1]