view tests/test-commit-unresolved.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

  $ addcommit () {
  >     echo $1 > $1
  >     hg add $1
  >     hg commit -d "${2} 0" -m $1
  > }

  $ commit () {
  >     hg commit -d "${2} 0" -m $1
  > }

  $ hg init a
  $ cd a
  $ addcommit "A" 0
  $ addcommit "B" 1
  $ echo "C" >> A
  $ commit "C" 2

  $ hg update -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo "D" >> A
  $ commit "D" 3
  created new head

State before the merge

  $ hg status
  $ hg id
  e45016d2b3d3 tip
  $ hg summary
  parent: 3:e45016d2b3d3 tip
   D
  branch: default
  commit: (clean)
  update: 2 new changesets, 2 branch heads (merge)
  phases: 4 draft

Testing the abort functionality first in case of conflicts

  $ hg merge --abort
  abort: no merge in progress
  [255]
  $ hg merge
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]

  $ hg merge --abort e4501
  abort: cannot specify a node with --abort
  [255]
  $ hg merge --abort --rev e4501
  abort: cannot specify both --rev and --abort
  [255]

  $ hg merge --abort
  aborting the merge, updating back to e45016d2b3d3
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

Checking that we got back in the same state

  $ hg status
  ? A.orig
  $ hg id
  e45016d2b3d3 tip
  $ hg summary
  parent: 3:e45016d2b3d3 tip
   D
  branch: default
  commit: 1 unknown (clean)
  update: 2 new changesets, 2 branch heads (merge)
  phases: 4 draft

Merging a conflict araises

  $ hg merge
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]

Correct the conflict without marking the file as resolved

  $ echo "ABCD" > A
  $ hg commit -m "Merged"
  abort: unresolved merge conflicts (see 'hg help resolve')
  [255]

Mark the conflict as resolved and commit

  $ hg resolve -m A
  (no more unresolved files)
  $ hg commit -m "Merged"

Test that if a file is removed but not marked resolved, the commit still fails
(issue4972)

  $ hg up ".^"
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg merge 2
  merging A
  warning: conflicts while merging A! (edit, then use 'hg resolve --mark')
  1 files updated, 0 files merged, 0 files removed, 1 files unresolved
  use 'hg resolve' to retry unresolved file merges or 'hg merge --abort' to abandon
  [1]
  $ hg rm --force A
  $ hg commit -m merged
  abort: unresolved merge conflicts (see 'hg help resolve')
  [255]

  $ hg resolve -ma
  (no more unresolved files)
  $ hg commit -m merged
  created new head

Testing the abort functionality in case of no conflicts

  $ hg update -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ addcommit "E" 4
  created new head
  $ hg id
  68352a18a7c4 tip

  $ hg merge -r 4
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg merge --preview --abort
  abort: cannot specify --preview with --abort
  [255]

  $ hg merge --abort
  aborting the merge, updating back to 68352a18a7c4
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg id
  68352a18a7c4 tip

  $ cd ..