view tests/test-contrib-check-commit.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 'check-commit' script
==============================

A fine patch:

  $ cat > patch-with-long-header.diff << EOF
  > # HG changeset patch
  > # User timeless <[e-mail]>
  > # Date 1448911706 0
  > #      Mon Nov 30 19:28:26 2015 +0000
  > # Node ID c41cb6d2b7dbd62b1033727f8606b8c09fc4aa88
  > # Parent  42aa0e570eaa364a622bc4443b0bcb79b1100a58
  > # ClownJoke This is a veryly long header that should not be warned about because its not the description
  > bundle2: use Oxford comma (issue123) (BC)
  > 
  > diff --git a/hgext/transplant.py b/hgext/transplant.py
  > --- a/hgext/transplant.py
  > +++ b/hgext/transplant.py
  > @@ -599,7 +599,7 @@
  >              return
  >          if not (opts.get('source') or revs or
  >                  opts.get('merge') or opts.get('branch')):
  > -            raise error.Abort(_('no source URL, branch revision or revision '
  > +            raise error.Abort(_('no source URL, branch revision, or revision '
  >                                 'list provided'))
  >          if opts.get('all'):
  > 
  > + def blahblah(x):
  > +     pass
  > EOF
  $ cat patch-with-long-header.diff | $TESTDIR/../contrib/check-commit

This would normally be against the rules, but it's okay because that's
what tagging and signing looks like:

  $ cat > creates-a-tag.diff << EOF
  > # HG changeset patch
  > # User Augie Fackler <[e-mail]>
  > # Date 1484787778 18000
  > #      Wed Jan 18 20:02:58 2017 -0500
  > # Branch stable
  > # Node ID c177635e4acf52923bc3aa9f72a5b1ad1197b173
  > # Parent  a1dd2c0c479e0550040542e392e87bc91262517e
  > Added tag 4.1-rc for changeset a1dd2c0c479e
  > 
  > diff --git a/.hgtags b/.hgtags
  > --- a/.hgtags
  > +++ b/.hgtags
  > @@ -150,3 +150,4 @@ 438173c415874f6ac653efc1099dec9c9150e90f
  >  eab27446995210c334c3d06f1a659e3b9b5da769 4.0
  >  b3b1ae98f6a0e14c1e1ba806a6c18e193b6dae5c 4.0.1
  >  e69874dc1f4e142746ff3df91e678a09c6fc208c 4.0.2
  > +a1dd2c0c479e0550040542e392e87bc91262517e 4.1-rc
  > EOF
  $ $TESTDIR/../contrib/check-commit < creates-a-tag.diff

A patch with lots of errors:

  $ cat > patch-with-long-header.diff << EOF
  > # HG changeset patch
  > # User timeless
  > # Date 1448911706 0
  > #      Mon Nov 30 19:28:26 2015 +0000
  > # Node ID c41cb6d2b7dbd62b1033727f8606b8c09fc4aa88
  > # Parent  42aa0e570eaa364a622bc4443b0bcb79b1100a58
  > # ClownJoke This is a veryly long header that should not be warned about because its not the description
  > transplant/foo: this summary is way too long use Oxford comma (bc) (bug123) (issue 244)
  > 
  > diff --git a/hgext/transplant.py b/hgext/transplant.py
  > --- a/hgext/transplant.py
  > +++ b/hgext/transplant.py
  > @@ -599,7 +599,7 @@
  >              return
  >          if not (opts.get('source') or revs or
  >                  opts.get('merge') or opts.get('branch')):
  > -            raise error.Abort(_('no source URL, branch revision or revision '
  > +            raise error.Abort(_('no source URL, branch revision, or revision '
  >                                 'list provided'))
  >          if opts.get('all'):
  > EOF
  $ cat patch-with-long-header.diff | $TESTDIR/../contrib/check-commit
  1: username is not an email address
   # User timeless
  7: summary keyword should be most user-relevant one-word command or topic
   transplant/foo: this summary is way too long use Oxford comma (bc) (bug123) (issue 244)
  7: (BC) needs to be uppercase
   transplant/foo: this summary is way too long use Oxford comma (bc) (bug123) (issue 244)
  7: use (issueDDDD) instead of bug
   transplant/foo: this summary is way too long use Oxford comma (bc) (bug123) (issue 244)
  7: no space allowed between issue and number
   transplant/foo: this summary is way too long use Oxford comma (bc) (bug123) (issue 244)
  7: summary line too long (limit is 78)
   transplant/foo: this summary is way too long use Oxford comma (bc) (bug123) (issue 244)
  [1]

A patch with other errors:

  $ cat > patch-with-long-header.diff << EOF
  > # HG changeset patch
  > # User timeless
  > # Date 1448911706 0
  > #      Mon Nov 30 19:28:26 2015 +0000
  > # Node ID c41cb6d2b7dbd62b1033727f8606b8c09fc4aa88
  > # Parent  42aa0e570eaa364a622bc4443b0bcb79b1100a58
  > # ClownJoke This is a veryly long header that should not be warned about because its not the description
  > This has no topic and ends with a period.
  > 
  > diff --git a/hgext/transplant.py b/hgext/transplant.py
  > --- a/hgext/transplant.py
  > +++ b/hgext/transplant.py
  > @@ -599,7 +599,7 @@
  >          if opts.get('all'):
  >  
  > 
  > +
  > + some = otherjunk
  > +
  > +
  > + def blah_blah(x):
  > +     pass
  > +
  >  
  > EOF
  $ cat patch-with-long-header.diff | $TESTDIR/../contrib/check-commit
  1: username is not an email address
   # User timeless
  7: don't capitalize summary lines
   This has no topic and ends with a period.
  7: summary line doesn't start with 'topic: '
   This has no topic and ends with a period.
  7: don't add trailing period on summary line
   This has no topic and ends with a period.
  19: adds double empty line
   +
  20: adds a function with foo_bar naming
   + def blah_blah(x):
  23: adds double empty line
   +
  [1]