view tests/test-mq-git.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

# Test the plumbing of mq.git option
# Automatic upgrade itself is tested elsewhere.

  $ cat <<EOF >> $HGRCPATH
  > [extensions]
  > mq =
  > [diff]
  > nodates = 1
  > EOF

  $ hg init repo-auto
  $ cd repo-auto

git=auto: regular patch creation:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f adda

  $ cat .hg/patches/adda
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff -r 000000000000 -r ef8dafc9fa4c a
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,1 @@
  +a

git=auto: git patch creation with copy:

  $ hg cp a b
  $ hg qnew -d '0 0' -f copy

  $ cat .hg/patches/copy
  # HG changeset patch
  # Date 0 0
  # Parent  ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
  
  diff --git a/a b/b
  copy from a
  copy to b

git=auto: git patch when using --git:

  $ echo regular > regular
  $ hg add regular
  $ hg qnew -d '0 0' --git -f git

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  99586d5f048c399e20f81cee41fbb3809c0e735d
  
  diff --git a/regular b/regular
  new file mode 100644
  --- /dev/null
  +++ b/regular
  @@ -0,0 +1,1 @@
  +regular

git=auto: regular patch after qrefresh without --git:

  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  99586d5f048c399e20f81cee41fbb3809c0e735d
  
  diff -r 99586d5f048c regular
  --- /dev/null
  +++ b/regular
  @@ -0,0 +1,1 @@
  +regular

  $ cd ..

  $ hg init repo-keep
  $ cd repo-keep
  $ echo '[mq]' > .hg/hgrc
  $ echo 'git = KEEP' >> .hg/hgrc

git=keep: git patch with --git:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f --git git

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,1 @@
  +a

git=keep: git patch after qrefresh without --git:

  $ echo a >> a
  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,2 @@
  +a
  +a
  $ cd ..

  $ hg init repo-yes
  $ cd repo-yes
  $ echo '[mq]' > .hg/hgrc
  $ echo 'git = yes' >> .hg/hgrc

git=yes: git patch:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f git

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,1 @@
  +a

git=yes: git patch after qrefresh:

  $ echo a >> a
  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/git
  # HG changeset patch
  # Date 0 0
  # Parent  0000000000000000000000000000000000000000
  
  diff --git a/a b/a
  new file mode 100644
  --- /dev/null
  +++ b/a
  @@ -0,0 +1,2 @@
  +a
  +a
  $ cd ..

  $ hg init repo-no
  $ cd repo-no
  $ echo '[diff]' > .hg/hgrc
  $ echo 'git = True' >> .hg/hgrc
  $ echo '[mq]' > .hg/hgrc
  $ echo 'git = False' >> .hg/hgrc

git=no: regular patch with copy:

  $ echo a > a
  $ hg add a
  $ hg qnew -d '0 0' -f adda
  $ hg cp a b
  $ hg qnew -d '0 0' -f regular

  $ cat .hg/patches/regular
  # HG changeset patch
  # Date 0 0
  # Parent  ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
  
  diff -r ef8dafc9fa4c -r a70404f79ba3 b
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +a

git=no: regular patch after qrefresh with copy:

  $ hg cp a c
  $ hg qrefresh -d '0 0'

  $ cat .hg/patches/regular
  # HG changeset patch
  # Date 0 0
  # Parent  ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
  
  diff -r ef8dafc9fa4c b
  --- /dev/null
  +++ b/b
  @@ -0,0 +1,1 @@
  +a
  diff -r ef8dafc9fa4c c
  --- /dev/null
  +++ b/c
  @@ -0,0 +1,1 @@
  +a

Test how [diff] configuration influence and cause invalid or lossy patches:

  $ cat <<EOF >> .hg/hgrc
  > [mq]
  > git = AUTO
  > [diff]
  > nobinary = True
  > noprefix = True
  > showfunc = True
  > ignorews = True
  > ignorewsamount = True
  > ignoreblanklines = True
  > unified = 1
  > EOF

  $ echo ' a' > a
  $ hg qnew prepare -d '0 0'
  $ echo '  a' > a
  $ printf '\0' > b
  $ echo >> c
  $ hg qnew diff -d '0 0'

  $ cat .hg/patches/prepare
  # HG changeset patch
  # Date 0 0
  # Parent  cf0bfe72686a47d8d7d7b4529a3adb8b0b449a9f
  
  diff -r cf0bfe72686a -r fb9c4422b0f3 a
  --- a/a
  +++ b/a
  @@ -1,1 +1,1 @@
  -a
  + a
  $ cat .hg/patches/diff
  # HG changeset patch
  # Date 0 0
  # Parent  fb9c4422b0f37dd576522dd9a3f99b825c177efe
  
  diff --git a/a b/a
  --- a/a
  +++ b/a
  @@ -1,1 +1,1 @@
  - a
  +  a
  diff --git a/b b/b
  index 78981922613b2afb6025042ff6bd878ac1994e85..f76dd238ade08917e6712764a16a22005a50573d
  GIT binary patch
  literal 1
  Ic${MZ000310RR91
  
  diff --git a/c b/c
  --- a/c
  +++ b/c
  @@ -1,1 +1,2 @@
   a
  +

  $ cd ..