view tests/test-clone-r.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

  $ hg init test
  $ cd test

  $ echo 0 >> afile
  $ hg add afile
  $ hg commit -m "0.0"

  $ echo 1 >> afile
  $ hg commit -m "0.1"

  $ echo 2 >> afile
  $ hg commit -m "0.2"

  $ echo 3 >> afile
  $ hg commit -m "0.3"

  $ hg update -C 0
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ echo 1 >> afile
  $ hg commit -m "1.1"
  created new head

  $ echo 2 >> afile
  $ hg commit -m "1.2"

  $ echo a line > fred
  $ echo 3 >> afile
  $ hg add fred
  $ hg commit -m "1.3"
  $ hg mv afile adifferentfile
  $ hg commit -m "1.3m"

  $ hg update -C 3
  1 files updated, 0 files merged, 2 files removed, 0 files unresolved

  $ hg mv afile anotherfile
  $ hg commit -m "0.3m"

  $ hg debugindex -f 1 afile
     rev flag     size   link     p1     p2       nodeid
       0 0000        2      0     -1     -1 362fef284ce2
       1 0000        4      1      0     -1 125144f7e028
       2 0000        6      2      1     -1 4c982badb186
       3 0000        8      3      2     -1 19b1fc555737

  $ hg debugindex adifferentfile
     rev linkrev nodeid       p1           p2
       0       7 2565f3199a74 000000000000 000000000000

  $ hg debugindex anotherfile
     rev linkrev nodeid       p1           p2
       0       8 2565f3199a74 000000000000 000000000000

  $ hg debugindex fred
     rev linkrev nodeid       p1           p2
       0       6 12ab3bcc5ea4 000000000000 000000000000

  $ hg debugindex --manifest
     rev linkrev nodeid       p1           p2
       0       0 43eadb1d2d06 000000000000 000000000000
       1       1 8b89697eba2c 43eadb1d2d06 000000000000
       2       2 626a32663c2f 8b89697eba2c 000000000000
       3       3 f54c32f13478 626a32663c2f 000000000000
       4       6 de68e904d169 626a32663c2f 000000000000
       5       7 09bb521d218d de68e904d169 000000000000
       6       8 1fde233dfb0f f54c32f13478 000000000000

  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 9 changesets, 7 total revisions

  $ cd ..

  $ for i in 0 1 2 3 4 5 6 7 8; do
  >   echo
  >   echo ---- hg clone -r "$i" test test-"$i"
  >   hg clone -r "$i" test test-"$i"
  >   cd test-"$i"
  >   hg verify
  >   cd ..
  > done
  
  ---- hg clone -r 0 test test-0
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 1 changes to 1 files
  new changesets f9ee2f85a263
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 1 changesets, 1 total revisions
  
  ---- hg clone -r 1 test test-1
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets f9ee2f85a263:34c2bf6b0626
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions
  
  ---- hg clone -r 2 test test-2
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  new changesets f9ee2f85a263:e38ba6f5b7e0
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions
  
  ---- hg clone -r 3 test test-3
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 1 files
  new changesets f9ee2f85a263:eebf5a27f8ca
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 4 changesets, 4 total revisions
  
  ---- hg clone -r 4 test test-4
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets f9ee2f85a263:095197eb4973
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 2 changesets, 2 total revisions
  
  ---- hg clone -r 5 test test-5
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  new changesets f9ee2f85a263:1bb50a9436a7
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  1 files, 3 changesets, 3 total revisions
  
  ---- hg clone -r 6 test test-6
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 5 changes to 2 files
  new changesets f9ee2f85a263:7373c1169842
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 4 changesets, 5 total revisions
  
  ---- hg clone -r 7 test test-7
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 6 changes to 3 files
  new changesets f9ee2f85a263:a6a34bfa0076
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 5 changesets, 6 total revisions
  
  ---- hg clone -r 8 test test-8
  adding changesets
  adding manifests
  adding file changes
  added 5 changesets with 5 changes to 2 files
  new changesets f9ee2f85a263:aa35859c02ea
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 5 changesets, 5 total revisions

  $ cd test-8
  $ hg pull ../test-7
  pulling from ../test-7
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 2 changes to 3 files (+1 heads)
  new changesets 095197eb4973:a6a34bfa0076
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  4 files, 9 changesets, 7 total revisions
  $ cd ..

  $ hg clone test test-9
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd test-9
  $ hg branch foobar
  marked working directory as branch foobar
  (branches are permanent and global, did you want a bookmark?)
  $ echo file2 >> file2
  $ hg add file2
  $ hg commit -m "changeset9"
  $ echo file3 >> file3
  $ hg add file3
  $ hg commit -m "changeset10"
  $ cd ..
  $ hg clone -r 9 -u foobar test-9 test-10
  adding changesets
  adding manifests
  adding file changes
  added 6 changesets with 6 changes to 3 files
  new changesets f9ee2f85a263:7100abb79635
  updating to branch foobar
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved