view tests/test-audit-subrepo.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 illegal name
-----------------

on commit:

  $ hg init hgname
  $ cd hgname
  $ mkdir sub
  $ hg init sub/.hg
  $ echo 'sub/.hg = sub/.hg' >> .hgsub
  $ hg ci -qAm 'add subrepo "sub/.hg"'
  abort: path 'sub/.hg' is inside nested repo 'sub'
  [255]

prepare tampered repo (including the commit above):

  $ hg import --bypass -qm 'add subrepo "sub/.hg"' - <<'EOF'
  > diff --git a/.hgsub b/.hgsub
  > new file mode 100644
  > --- /dev/null
  > +++ b/.hgsub
  > @@ -0,0 +1,1 @@
  > +sub/.hg = sub/.hg
  > diff --git a/.hgsubstate b/.hgsubstate
  > new file mode 100644
  > --- /dev/null
  > +++ b/.hgsubstate
  > @@ -0,0 +1,1 @@
  > +0000000000000000000000000000000000000000 sub/.hg
  > EOF
  $ cd ..

on clone (and update):

  $ hg clone -q hgname hgname2
  abort: path 'sub/.hg' is inside nested repo 'sub'
  [255]

Test direct symlink traversal
-----------------------------

#if symlink

on commit:

  $ mkdir hgsymdir
  $ hg init hgsymdir/root
  $ cd hgsymdir/root
  $ ln -s ../out
  $ hg ci -qAm 'add symlink "out"'
  $ hg init ../out
  $ echo 'out = out' >> .hgsub
  $ hg ci -qAm 'add subrepo "out"'
  abort: subrepo 'out' traverses symbolic link
  [255]

prepare tampered repo (including the commit above):

  $ hg import --bypass -qm 'add subrepo "out"' - <<'EOF'
  > diff --git a/.hgsub b/.hgsub
  > new file mode 100644
  > --- /dev/null
  > +++ b/.hgsub
  > @@ -0,0 +1,1 @@
  > +out = out
  > diff --git a/.hgsubstate b/.hgsubstate
  > new file mode 100644
  > --- /dev/null
  > +++ b/.hgsubstate
  > @@ -0,0 +1,1 @@
  > +0000000000000000000000000000000000000000 out
  > EOF
  $ cd ../..

on clone (and update):

  $ mkdir hgsymdir2
  $ hg clone -q hgsymdir/root hgsymdir2/root
  abort: subrepo 'out' traverses symbolic link
  [255]
  $ ls hgsymdir2
  root

#endif

Test indirect symlink traversal
-------------------------------

#if symlink

on commit:

  $ mkdir hgsymin
  $ hg init hgsymin/root
  $ cd hgsymin/root
  $ ln -s ../out
  $ hg ci -qAm 'add symlink "out"'
  $ mkdir ../out
  $ hg init ../out/sub
  $ echo 'out/sub = out/sub' >> .hgsub
  $ hg ci -qAm 'add subrepo "out/sub"'
  abort: path 'out/sub' traverses symbolic link 'out'
  [255]

prepare tampered repo (including the commit above):

  $ hg import --bypass -qm 'add subrepo "out/sub"' - <<'EOF'
  > diff --git a/.hgsub b/.hgsub
  > new file mode 100644
  > --- /dev/null
  > +++ b/.hgsub
  > @@ -0,0 +1,1 @@
  > +out/sub = out/sub
  > diff --git a/.hgsubstate b/.hgsubstate
  > new file mode 100644
  > --- /dev/null
  > +++ b/.hgsubstate
  > @@ -0,0 +1,1 @@
  > +0000000000000000000000000000000000000000 out/sub
  > EOF
  $ cd ../..

on clone (and update):

  $ mkdir hgsymin2
  $ hg clone -q hgsymin/root hgsymin2/root
  abort: path 'out/sub' traverses symbolic link 'out'
  [255]
  $ ls hgsymin2
  root

#endif