view tests/test-mq-missingfiles.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

Issue835: qpush fails immediately when patching a missing file, but
remaining added files are still created empty which will trick a
future qrefresh.

  $ cat > writelines.py <<EOF
  > import sys
  > path = sys.argv[1]
  > args = sys.argv[2:]
  > assert (len(args) % 2) == 0
  > 
  > f = open(path, 'wb')
  > for i in range(len(args) // 2):
  >    count, s = args[2*i:2*i+2]
  >    count = int(count)
  >    s = s.decode('string_escape')
  >    f.write(s*count)
  > f.close()
  > EOF

  $ echo "[extensions]" >> $HGRCPATH
  $ echo "mq=" >> $HGRCPATH

  $ hg init normal
  $ cd normal
  $ $PYTHON ../writelines.py b 10 'a\n'
  $ hg ci -Am addb
  adding b
  $ echo a > a
  $ $PYTHON ../writelines.py b 2 'b\n' 10 'a\n' 2 'c\n'
  $ echo c > c
  $ hg add a c
  $ hg qnew -f changeb
  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg rm b
  $ hg ci -Am rmb

Push patch with missing target:

  $ hg qpush
  applying changeb
  unable to find 'b' for patching
  (use '--prefix' to apply patch relative to the current directory)
  2 out of 2 hunks FAILED -- saving rejects to file b.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changeb
  [2]

Display added files:

  $ cat a
  a
  $ cat c
  c

Display rejections:

  $ cat b.rej
  --- b
  +++ b
  @@ -1,3 +1,5 @@
  +b
  +b
   a
   a
   a
  @@ -8,3 +10,5 @@
   a
   a
   a
  +c
  +c

Test missing renamed file

  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg up -qC 0
  $ echo a > a
  $ hg mv b bb
  $ $PYTHON ../writelines.py bb 2 'b\n' 10 'a\n' 2 'c\n'
  $ echo c > c
  $ hg add a c
  $ hg qnew changebb
  $ hg qpop
  popping changebb
  patch queue now empty
  $ hg up -qC 1
  $ hg qpush
  applying changebb
  patching file bb
  Hunk #1 FAILED at 0
  Hunk #2 FAILED at 7
  2 out of 2 hunks FAILED -- saving rejects to file bb.rej
  b not tracked!
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changebb
  [2]
  $ cat a
  a
  $ cat c
  c
  $ cat bb.rej
  --- bb
  +++ bb
  @@ -1,3 +1,5 @@
  +b
  +b
   a
   a
   a
  @@ -8,3 +10,5 @@
   a
   a
   a
  +c
  +c

  $ cd ..


  $ echo "[diff]" >> $HGRCPATH
  $ echo "git=1" >> $HGRCPATH

  $ hg init git
  $ cd git
  $ $PYTHON ../writelines.py b 1 '\x00'
  $ hg ci -Am addb
  adding b
  $ echo a > a
  $ $PYTHON ../writelines.py b 1 '\x01' 1 '\x00'
  $ echo c > c
  $ hg add a c
  $ hg qnew -f changeb
  $ hg qpop
  popping changeb
  patch queue now empty
  $ hg rm b
  $ hg ci -Am rmb

Push git patch with missing target:

  $ hg qpush
  applying changeb
  unable to find 'b' for patching
  (use '--prefix' to apply patch relative to the current directory)
  1 out of 1 hunks FAILED -- saving rejects to file b.rej
  patch failed, unable to continue (try -v)
  patch failed, rejects left in working directory
  errors during apply, please fix and qrefresh changeb
  [2]
  $ hg st
  ? b.rej

Display added files:

  $ cat a
  a
  $ cat c
  c

Display rejections:

  $ cat b.rej
  --- b
  +++ b
  GIT binary patch
  literal 2
  Jc${No0000400IC2
  
  $ cd ..

Test push creating directory during git copy or rename:

  $ hg init missingdir
  $ cd missingdir
  $ echo a > a
  $ hg ci -Am adda
  adding a
  $ mkdir d
  $ hg copy a d/a2
  $ hg mv a d/a
  $ hg qnew -g -f patch
  $ hg qpop
  popping patch
  patch queue now empty
  $ hg qpush
  applying patch
  now at: patch

  $ cd ..