view tests/test-directaccess.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

Tests for access level on hidden commits by various commands on based of their
type.

Setting the required config to start this

  $ cat >> $HGRCPATH <<EOF
  > [experimental]
  > evolution=createmarkers, allowunstable
  > directaccess=True
  > directaccess.revnums=True
  > [extensions]
  > amend =
  > EOF

  $ hg init repo
  $ cd repo
  $ for ch in a b c; do touch $ch; echo "foo" >> $ch; hg ci -Aqm "Added "$ch; done

  $ hg log -G -T '{rev}:{node} {desc}' --hidden
  @  2:28ad74487de9599d00d81085be739c61fc340652 Added c
  |
  o  1:29becc82797a4bc11ec8880b58eaecd2ab3e7760 Added b
  |
  o  0:18d04c59bb5d2d4090ad9a5b59bd6274adb63add Added a
  
  $ echo "bar" >> c
  $ hg amend

  $ hg log -G -T '{rev}:{node} {desc}' --hidden
  @  3:2443a0e664694756d8b435d06b6ad84f941b6fc0 Added c
  |
  | x  2:28ad74487de9599d00d81085be739c61fc340652 Added c
  |/
  o  1:29becc82797a4bc11ec8880b58eaecd2ab3e7760 Added b
  |
  o  0:18d04c59bb5d2d4090ad9a5b59bd6274adb63add Added a
  
Testing read only commands on the hidden revision

Testing with rev number

  $ hg exp 2 --config experimental.directaccess.revnums=False
  abort: hidden revision '2' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

  $ hg exp 2
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 28ad74487de9599d00d81085be739c61fc340652
  # Parent  29becc82797a4bc11ec8880b58eaecd2ab3e7760
  Added c
  
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

  $ hg log -r 2
  changeset:   2:28ad74487de9
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  obsolete:    rewritten using amend as 3:2443a0e66469
  summary:     Added c
  
  $ hg identify -r 2
  28ad74487de9

  $ hg status --change 2
  A c

  $ hg status --change 2 --config experimental.directaccess.revnums=False
  abort: hidden revision '2' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

  $ hg diff -c 2
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

Testing with hash

`hg export`

  $ hg exp 28ad74
  # HG changeset patch
  # User test
  # Date 0 0
  #      Thu Jan 01 00:00:00 1970 +0000
  # Node ID 28ad74487de9599d00d81085be739c61fc340652
  # Parent  29becc82797a4bc11ec8880b58eaecd2ab3e7760
  Added c
  
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

`hg log`

  $ hg log -r 28ad74
  changeset:   2:28ad74487de9
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  obsolete:    rewritten using amend as 3:2443a0e66469
  summary:     Added c
  
`hg cat`

  $ hg cat -r 28ad74 c
  foo

`hg diff`

  $ hg diff -c 28ad74
  diff -r 29becc82797a -r 28ad74487de9 c
  --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -0,0 +1,1 @@
  +foo

`hg files`

  $ hg files -r 28ad74
  a
  b
  c

`hg identify`

  $ hg identify -r 28ad74
  28ad74487de9

`hg annotate`

  $ hg annotate -r 28ad74 a
  0: foo

`hg status`

  $ hg status --change 28ad74
  A c

`hg archive`

This should not throw error
  $ hg archive -r 28ad74 foo

`hg update`

  $ hg up 28ad74
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  updated to hidden changeset 28ad74487de9
  (hidden revision '28ad74487de9' was rewritten as: 2443a0e66469)

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

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

`hg revert`

  $ hg revert -r 28ad74 --all
  reverting c

  $ hg diff
  diff -r 2443a0e66469 c
  --- a/c	Thu Jan 01 00:00:00 1970 +0000
  +++ b/c	Thu Jan 01 00:00:00 1970 +0000
  @@ -1,2 +1,1 @@
   foo
  -bar

Test special hash/rev

  $ hg log -qr 'null:wdir() & 000000000000'
  -1:000000000000
  $ hg log -qr 'null:wdir() & ffffffffffff'
  2147483647:ffffffffffff
  $ hg log -qr 'null:wdir() & rev(-1)'
  -1:000000000000
  $ hg log -qr 'null:wdir() & rev(2147483647)'
  2147483647:ffffffffffff
  $ hg log -qr 'null:wdir() & 2147483647'
  2147483647:ffffffffffff

Commands with undefined intent should not work right now

  $ hg phase -r 28ad74
  abort: hidden revision '28ad74' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

  $ hg phase -r 2
  abort: hidden revision '2' was rewritten as: 2443a0e66469!
  (use --hidden to access hidden revisions)
  [255]

Setting a bookmark will make that changeset unhidden, so this should come in end

  $ hg bookmarks -r 28ad74 book
  bookmarking hidden changeset 28ad74487de9
  (hidden revision '28ad74487de9' was rewritten as: 2443a0e66469)

  $ hg bookmarks
     book                      2:28ad74487de9