view tests/test-rebase-detach.t @ 39561:d06834e0f48e

wireprotov2peer: stream decoded responses

Previously, wire protocol version 2 would buffer all response data.
Only once all data was received did we CBOR decode it and resolve
the future associated with the command. This was obviously not
desirable. In future commits that introduce large response payloads,
this caused significant memory bloat and slowed down client
operations due to waiting on the server.

This commit refactors the response handling code so that response
data can be streamed.

Command response objects now contain a buffered CBOR decoder. As
new data arrives, it is fed into the decoder. Decoded objects are
made available to the generator as they are decoded.

Because there is a separate thread processing incoming frames and
feeding data into the response object, there is the potential for
race conditions when mutating response objects. So a lock has been
added to guard access to critical state variables.

Because the generator emitting decoded objects needs to wait on
those objects to become available, we've added an Event for the
generator to wait on so it doesn't busy loop. This does mean
there is the potential for deadlocks. And I'm pretty sure they can
occur in some scenarios. We already have a handful of TODOs around
this. But I've added some more. Fixing this will likely require
moving the background thread receiving frames into clienthandler.
We likely would have done this anyway when implementing the client
bits for the SSH transport.

Test output changes because the initial CBOR map holding the overall
response state is now always handled internally by the response
object.

Differential Revision: https://phab.mercurial-scm.org/D4474

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {node|short} '{desc}'\n"
  > 
  > [extensions]
  > drawdag=$TESTDIR/drawdag.py
  > EOF

Rebasing D onto B detaching from C (one commit):

  $ hg init a1
  $ cd a1

  $ hg debugdrawdag <<EOF
  > D
  > |
  > C B
  > |/
  > A
  > EOF
  $ hg phase --force --secret D

  $ hg rebase -s D -d B
  rebasing 3:e7b3f00ed42e "D" (D tip)
  saved backup bundle to $TESTTMP/a1/.hg/strip-backup/e7b3f00ed42e-6f368371-rebase.hg

  $ hg log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  o  3:secret 'D'
  |
  | o  2:draft 'C'
  | |
  o |  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ hg manifest --rev tip
  A
  B
  D

  $ cd ..


Rebasing D onto B detaching from C (two commits):

  $ hg init a2
  $ cd a2

  $ hg debugdrawdag <<EOF
  > E
  > |
  > D
  > |
  > C B
  > |/
  > A
  > EOF

  $ hg rebase -s D -d B
  rebasing 3:e7b3f00ed42e "D" (D)
  rebasing 4:69a34c08022a "E" (E tip)
  saved backup bundle to $TESTTMP/a2/.hg/strip-backup/e7b3f00ed42e-a2ec7cea-rebase.hg

  $ hg tglog
  o  4: ee79e0744528 'E'
  |
  o  3: 10530e1d72d9 'D'
  |
  | o  2: dc0947a82db8 'C'
  | |
  o |  1: 112478962961 'B'
  |/
  o  0: 426bada5c675 'A'
  
  $ hg manifest --rev tip
  A
  B
  D
  E

  $ cd ..

Rebasing C onto B using detach (same as not using it):

  $ hg init a3
  $ cd a3

  $ hg debugdrawdag <<EOF
  > D
  > |
  > C B
  > |/
  > A
  > EOF

  $ hg rebase -s C -d B
  rebasing 2:dc0947a82db8 "C" (C)
  rebasing 3:e7b3f00ed42e "D" (D tip)
  saved backup bundle to $TESTTMP/a3/.hg/strip-backup/dc0947a82db8-b8481714-rebase.hg

  $ hg tglog
  o  3: 7375f3dbfb0f 'D'
  |
  o  2: bbfdd6cb49aa 'C'
  |
  o  1: 112478962961 'B'
  |
  o  0: 426bada5c675 'A'
  
  $ hg manifest --rev tip
  A
  B
  C
  D

  $ cd ..


Rebasing D onto B detaching from C and collapsing:

  $ hg init a4
  $ cd a4

  $ hg debugdrawdag <<EOF
  > E
  > |
  > D
  > |
  > C B
  > |/
  > A
  > EOF
  $ hg phase --force --secret E

  $ hg rebase --collapse -s D -d B
  rebasing 3:e7b3f00ed42e "D" (D)
  rebasing 4:69a34c08022a "E" (E tip)
  saved backup bundle to $TESTTMP/a4/.hg/strip-backup/e7b3f00ed42e-a2ec7cea-rebase.hg

  $ hg  log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  o  3:secret 'Collapsed revision
  |  * D
  |  * E'
  | o  2:draft 'C'
  | |
  o |  1:draft 'B'
  |/
  o  0:draft 'A'
  
  $ hg manifest --rev tip
  A
  B
  D
  E

  $ cd ..

Rebasing across null as ancestor
  $ hg init a5
  $ cd a5

  $ hg debugdrawdag <<EOF
  > E
  > |
  > D
  > |
  > C
  > |
  > A B
  > EOF

  $ hg rebase -s C -d B
  rebasing 2:dc0947a82db8 "C" (C)
  rebasing 3:e7b3f00ed42e "D" (D)
  rebasing 4:69a34c08022a "E" (E tip)
  saved backup bundle to $TESTTMP/a5/.hg/strip-backup/dc0947a82db8-3eefec98-rebase.hg

  $ hg tglog
  o  4: e3d0c70d606d 'E'
  |
  o  3: e9153d36a1af 'D'
  |
  o  2: a7ac28b870a8 'C'
  |
  o  1: fc2b737bb2e5 'B'
  
  o  0: 426bada5c675 'A'
  
  $ hg rebase -d 1 -s 3
  rebasing 3:e9153d36a1af "D"
  rebasing 4:e3d0c70d606d "E" (tip)
  saved backup bundle to $TESTTMP/a5/.hg/strip-backup/e9153d36a1af-db7388ed-rebase.hg
  $ hg tglog
  o  4: 2c24e540eccd 'E'
  |
  o  3: 73f786ed52ff 'D'
  |
  | o  2: a7ac28b870a8 'C'
  |/
  o  1: fc2b737bb2e5 'B'
  
  o  0: 426bada5c675 'A'
  
  $ cd ..

Verify that target is not selected as external rev (issue3085)

  $ hg init a6
  $ cd a6

  $ hg debugdrawdag <<EOF
  > H
  > | G
  > |/|
  > F E
  > |/
  > A
  > EOF
  $ hg up -q G

  $ echo "I" >> E
  $ hg ci -m "I"
  $ hg tag --local I
  $ hg merge H
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m "Merge"
  $ echo "J" >> F
  $ hg ci -m "J"
  $ hg tglog
  @  7: c6aaf0d259c0 'J'
  |
  o    6: 0cfbc7e8faaf 'Merge'
  |\
  | o  5: b92d164ad3cb 'I'
  | |
  o |  4: 4ea5b230dea3 'H'
  | |
  | o  3: c6001eacfde5 'G'
  |/|
  o |  2: 8908a377a434 'F'
  | |
  | o  1: 7fb047a69f22 'E'
  |/
  o  0: 426bada5c675 'A'
  
  $ hg rebase -s I -d H --collapse --config ui.merge=internal:other
  rebasing 5:b92d164ad3cb "I" (I)
  rebasing 6:0cfbc7e8faaf "Merge"
  rebasing 7:c6aaf0d259c0 "J" (tip)
  saved backup bundle to $TESTTMP/a6/.hg/strip-backup/b92d164ad3cb-88fd7ab7-rebase.hg

  $ hg tglog
  @  5: 65079693dac4 'Collapsed revision
  |  * I
  |  * Merge
  |  * J'
  o  4: 4ea5b230dea3 'H'
  |
  | o  3: c6001eacfde5 'G'
  |/|
  o |  2: 8908a377a434 'F'
  | |
  | o  1: 7fb047a69f22 'E'
  |/
  o  0: 426bada5c675 'A'
  

  $ hg log --rev tip
  changeset:   5:65079693dac4
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Collapsed revision
  

  $ cd ..

Ensure --continue restores a correct state (issue3046) and phase:
  $ hg init a7
  $ cd a7

  $ hg debugdrawdag <<EOF
  > C B
  > |/
  > A
  > EOF
  $ hg up -q C
  $ echo 'B2' > B
  $ hg ci -A -m 'B2'
  adding B
  $ hg phase --force --secret .
  $ hg rebase -s . -d B --config ui.merge=internal:fail
  rebasing 3:17b4880d2402 "B2" (tip)
  merging B
  warning: conflicts while merging B! (edit, then use 'hg resolve --mark')
  unresolved conflicts (see hg resolve, then hg rebase --continue)
  [1]
  $ hg resolve --all -t internal:local
  (no more unresolved files)
  continue: hg rebase --continue
  $ hg rebase -c
  rebasing 3:17b4880d2402 "B2" (tip)
  note: rebase of 3:17b4880d2402 created no changes to commit
  saved backup bundle to $TESTTMP/a7/.hg/strip-backup/17b4880d2402-1ae1f6cc-rebase.hg
  $ hg  log -G --template "{rev}:{phase} '{desc}' {branches}\n"
  o  2:draft 'C'
  |
  | @  1:draft 'B'
  |/
  o  0:draft 'A'
  

  $ cd ..