view tests/test-audit-subrepo.t @ 37631:2f626233859b

wireproto: implement batching on peer executor interface

This is a bit more complicated than non-batch requests because we
need to buffer sends until the last request arrives *and* we need
to support resolving futures as data arrives from the remote.

In a classical concurrent.futures executor model, the future
"starts" as soon as it is submitted. However, we have nothing to
start until the last command is submitted.

If we did nothing, calling result() would deadlock, since the future
hasn't "started." So in the case where we queue the command, we return
a special future type whose result() will trigger sendcommands().
This eliminates the deadlock potential. It also serves as a check
against callers who may be calling result() prematurely, as it will
prevent any subsequent callcommands() from working. This behavior
is slightly annoying and a bit restrictive. But it's the world
that half duplex connections forces on us.

In order to support streaming responses, we were previously using
a generator. But with a futures-based API, we're using futures
and not generators. So in order to get streaming, we need a
background thread to read data from the server.

The approach taken in this patch is to leverage the ThreadPoolExecutor
from concurrent.futures for managing a background thread. We create
an executor and future that resolves when all response data is
processed (or an error occurs). When exiting the context manager,
we wait on that background reading before returning.

I was hoping we could manually spin up a threading.Thread and this
would be simple. But I ran into a few deadlocks when implementing.
After looking at the source code to concurrent.futures, I figured
it would just be easier to use a ThreadPoolExecutor than implement
all the code needed to manually manage a thread.

To prove this works, a use of the batch API in discovery has been
updated.

Differential Revision: https://phab.mercurial-scm.org/D3269

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