view tests/test-merge-default.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

  $ hg init
  $ echo a > a
  $ hg commit -A -ma
  adding a

  $ echo b >> a
  $ hg commit -mb

  $ echo c >> a
  $ hg commit -mc

  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo d >> a
  $ hg commit -md
  created new head

  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo e >> a
  $ hg commit -me
  created new head

  $ hg up 1
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Should fail because not at a head:

  $ hg merge
  abort: working directory not at a head revision
  (use 'hg update' or merge with an explicit revision)
  [255]

  $ hg up
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to "f25cbe84d8b3: e"
  2 other heads for branch "default"

Should fail because > 2 heads:

  $ HGMERGE=internal:other; export HGMERGE
  $ hg merge
  abort: branch 'default' has 3 heads - please merge with an explicit rev
  (run 'hg heads .' to see heads)
  [255]

Should succeed:

  $ hg merge 2
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg id -Tjson
  [
   {
    "bookmarks": [],
    "branch": "default",
    "dirty": "+",
    "id": "f25cbe84d8b3+2d95304fed5d+",
    "node": "ffffffffffffffffffffffffffffffffffffffff",
    "parents": [{"node": "f25cbe84d8b320e298e7703f18a25a3959518c23", "rev": 4}, {"node": "2d95304fed5d89bc9d70b2a0d02f0d567469c3ab", "rev": 2}],
    "tags": ["tip"]
   }
  ]
  $ hg commit -mm1

Should succeed - 2 heads:

  $ hg merge -P
  changeset:   3:ea9ff125ff88
  parent:      1:1846eede8b68
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     d
  
  $ hg merge
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg commit -mm2

  $ hg id -r 1 -Tjson
  [
   {
    "bookmarks": [],
    "branch": "default",
    "id": "1846eede8b68",
    "node": "1846eede8b6886d8cc8a88c96a687b7fe8f3b9d1",
    "tags": []
   }
  ]

Should fail because at tip:

  $ hg merge
  abort: nothing to merge
  [255]

  $ hg up 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

Should fail because there is only one head:

  $ hg merge
  abort: nothing to merge
  (use 'hg update' instead)
  [255]

  $ hg up 3
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo f >> a
  $ hg branch foobranch
  marked working directory as branch foobranch
  (branches are permanent and global, did you want a bookmark?)
  $ hg commit -mf

Should fail because merge with other branch:

  $ hg merge
  abort: branch 'foobranch' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]


Test for issue2043: ensure that 'merge -P' shows ancestors of 6 that
are not ancestors of 7, regardless of where their common ancestors are.

Merge preview not affected by common ancestor:

  $ hg up -q 7
  $ hg merge -q -P 6
  2:2d95304fed5d
  4:f25cbe84d8b3
  5:a431fabd6039
  6:e88e33f3bf62

Test experimental destination revset

  $ hg log -r '_destmerge()'
  abort: branch 'foobranch' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]

(on a branch with a two heads)

  $ hg up 5
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo f >> a
  $ hg commit -mf
  created new head
  $ hg log -r '_destmerge()'
  changeset:   6:e88e33f3bf62
  parent:      5:a431fabd6039
  parent:      3:ea9ff125ff88
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     m2
  

(from the other head)

  $ hg log -r '_destmerge(e88e33f3bf62)'
  changeset:   8:b613918999e2
  tag:         tip
  parent:      5:a431fabd6039
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     f
  

(from unrelated branch)

  $ hg log -r '_destmerge(foobranch)'
  abort: branch 'foobranch' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]