view tests/test-mq-safety.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

  $ echo '[extensions]' >> $HGRCPATH
  $ echo 'hgext.mq =' >> $HGRCPATH

  $ hg init repo
  $ cd repo

  $ echo foo > foo
  $ hg ci -qAm 'add a file'

  $ hg qinit

  $ hg qnew foo
  $ echo foo >> foo
  $ hg qrefresh -m 'append foo'

  $ hg qnew bar
  $ echo bar >> foo
  $ hg qrefresh -m 'append bar'

Try to operate on public mq changeset

  $ hg qpop
  popping bar
  now at: foo
  $ hg phase --public qbase
  $ echo babar >> foo
  $ hg qref
  abort: cannot qrefresh public revision
  (see 'hg help phases' for details)
  [255]
  $ hg revert -a
  reverting foo
  $ hg qpop
  abort: popping would remove a public revision
  (see 'hg help phases' for details)
  [255]
  $ hg qfold bar
  abort: cannot qrefresh public revision
  (see 'hg help phases' for details)
  [255]
  $ hg revert -a
  reverting foo

restore state for remaining test

  $ hg qpush
  applying bar
  now at: bar

try to commit on top of a patch

  $ echo quux >> foo
  $ hg ci -m 'append quux'
  abort: cannot commit over an applied mq patch
  [255]


cheat a bit...

  $ mv .hg/patches .hg/patches2
  $ hg ci -m 'append quux'
  $ mv .hg/patches2 .hg/patches


qpop/qrefresh on the wrong revision

  $ hg qpop
  abort: popping would remove a revision not managed by this patch queue
  [255]
  $ hg qpop -n patches
  using patch queue: $TESTTMP/repo/.hg/patches
  abort: popping would remove a revision not managed by this patch queue
  [255]
  $ hg qrefresh
  abort: working directory revision is not qtip
  [255]

  $ hg up -C qtip
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg qpop
  abort: popping would remove a revision not managed by this patch queue
  [255]
  $ hg qrefresh
  abort: cannot qrefresh a revision with children
  [255]
  $ hg tip --template '{rev} {desc}\n'
  3 append quux


qpush warning branchheads

  $ cd ..
  $ hg init branchy
  $ cd branchy
  $ echo q > q
  $ hg add q
  $ hg qnew -f qp
  $ hg qpop
  popping qp
  patch queue now empty
  $ echo a > a
  $ hg ci -Ama
  adding a
  $ hg up null
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg branch b
  marked working directory as branch b
  (branches are permanent and global, did you want a bookmark?)
  $ echo c > c
  $ hg ci -Amc
  adding c
  $ hg merge default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -mmerge
  $ hg up default
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg log
  changeset:   2:65309210bf4e
  branch:      b
  tag:         tip
  parent:      1:707adb4c8ae1
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     merge
  
  changeset:   1:707adb4c8ae1
  branch:      b
  parent:      -1:000000000000
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
  changeset:   0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a
  
  $ hg qpush
  applying qp
  now at: qp

Testing applied patches, push and --force

  $ cd ..
  $ hg init forcepush
  $ cd forcepush
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ echo a >> a
  $ hg ci -m changea
  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch branch
  marked working directory as branch branch
  (branches are permanent and global, did you want a bookmark?)
  $ echo b > b
  $ hg ci -Am addb
  adding b
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg --cwd .. clone -r 0 forcepush forcepush2
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets 07f494440405
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo a >> a
  $ hg qnew patch

Pushing applied patch with --rev without --force

  $ hg push -r . ../forcepush2
  pushing to ../forcepush2
  abort: source has mq patches applied
  [255]

Pushing applied patch with branchhash, without --force

  $ hg push ../forcepush2#default
  pushing to ../forcepush2
  abort: source has mq patches applied
  [255]

Pushing revs excluding applied patch

  $ hg push --new-branch -r 'branch(branch)' -r 2 ../forcepush2
  pushing to ../forcepush2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files

Pushing applied patch with --force

  $ hg phase --force --secret 'mq()'
  $ hg push --force -r default ../forcepush2
  pushing to ../forcepush2
  searching for changes
  no changes found (ignored 1 secret changesets)
  [1]
  $ hg phase --draft 'mq()'
  $ hg push --force -r default ../forcepush2
  pushing to ../forcepush2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files (+1 heads)

  $ cd ..