view tests/test-convert-hg-source.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

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > convert=
  > [convert]
  > hg.saverev=False
  > EOF
  $ hg init orig
  $ cd orig
  $ echo foo > foo
  $ echo bar > bar
  $ hg ci -qAm 'add foo bar' -d '0 0'
  $ echo >> foo
  $ hg ci -m 'change foo' -d '1 0'
  $ hg up -qC 0
  $ hg copy --after --force foo bar
  $ hg copy foo baz
  $ hg ci -m 'make bar and baz copies of foo' -d '2 0'
  created new head

Test that template can print all file copies (issue4362)
  $ hg log -r . --template "{file_copies % ' File: {file_copy}\n'}"
   File: bar (foo)
   File: baz (foo)

  $ hg bookmark premerge1
  $ hg merge -r 1
  merging baz and foo to baz
  1 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge local copy' -d '3 0'
  $ hg up -C 1
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved
  (leaving bookmark premerge1)
  $ hg bookmark premerge2
  $ hg merge 2
  merging foo and baz to baz
  1 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m 'merge remote copy' -d '4 0'
  created new head

Make and delete some tags

  $ hg tag that
  $ hg tag --remove that
  $ hg tag this

#if execbit
  $ chmod +x baz
#else
  $ echo some other change to make sure we get a rev 5 > baz
#endif
  $ hg ci -m 'mark baz executable' -d '5 0'
  $ cd ..
  $ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
  initializing destination new repository
  scanning source...
  sorting...
  converting...
  8 add foo bar
  7 change foo
  6 make bar and baz copies of foo
  5 merge local copy
  4 merge remote copy
  3 Added tag that for changeset 88586c4e9f02
  2 Removed tag that
  1 Added tag this for changeset c56a7f387039
  0 mark baz executable
  updating bookmarks
  $ cd new
  $ hg out ../orig
  comparing with ../orig
  searching for changes
  no changes found
  [1]
#if execbit
  $ hg bookmarks
     premerge1                 3:973ef48a98a4
     premerge2                 8:91d107c423ba
#else
Different hash because no x bit
  $ hg bookmarks
     premerge1                 3:973ef48a98a4
     premerge2                 8:3537b15eaaca
#endif

Test that redoing a convert results in an identical graph
  $ cd ../
  $ rm new/.hg/shamap
  $ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
  scanning source...
  sorting...
  converting...
  8 add foo bar
  7 change foo
  6 make bar and baz copies of foo
  5 merge local copy
  4 merge remote copy
  3 Added tag that for changeset 88586c4e9f02
  2 Removed tag that
  1 Added tag this for changeset c56a7f387039
  0 mark baz executable
  updating bookmarks
  $ hg -R new log -G -T '{rev} {desc}'
  o  8 mark baz executable
  |
  o  7 Added tag this for changeset c56a7f387039
  |
  o  6 Removed tag that
  |
  o  5 Added tag that for changeset 88586c4e9f02
  |
  o    4 merge remote copy
  |\
  +---o  3 merge local copy
  | |/
  | o  2 make bar and baz copies of foo
  | |
  o |  1 change foo
  |/
  o  0 add foo bar
  

check shamap LF and CRLF handling

  $ cat > rewrite.py <<EOF
  > import sys
  > # Interlace LF and CRLF
  > lines = [(l.rstrip() + ((i % 2) and b'\n' or b'\r\n'))
  >          for i, l in enumerate(open(sys.argv[1], 'rb'))]
  > open(sys.argv[1], 'wb').write(b''.join(lines))
  > EOF
  $ $PYTHON rewrite.py new/.hg/shamap
  $ cd orig
  $ hg up -qC 1
  $ echo foo >> foo
  $ hg ci -qm 'change foo again'
  $ hg up -qC 2
  $ echo foo >> foo
  $ hg ci -qm 'change foo again again'
  $ cd ..
  $ hg convert --datesort orig new 2>&1 | grep -v 'subversion python bindings could not be loaded'
  scanning source...
  sorting...
  converting...
  1 change foo again again
  0 change foo again
  updating bookmarks

init broken repository

  $ hg init broken
  $ cd broken
  $ echo a >> a
  $ echo b >> b
  $ hg ci -qAm init
  $ echo a >> a
  $ echo b >> b
  $ hg copy b c
  $ hg ci -qAm changeall
  $ hg up -qC 0
  $ echo bc >> b
  $ hg ci -m changebagain
  created new head
  $ HGMERGE=internal:local hg -q merge
  $ hg ci -m merge
  $ hg mv b d
  $ hg ci -m moveb

break it

#if reporevlogstore
  $ rm .hg/store/data/b.*
#endif
#if reposimplestore
  $ rm .hg/store/data/b/*
#endif
  $ cd ..
  $ hg --config convert.hg.ignoreerrors=True convert broken fixed
  initializing destination fixed repository
  scanning source...
  sorting...
  converting...
  4 init
  ignoring: data/b.i@1e88685f5dde: no match found (reporevlogstore !)
  ignoring: data/b/index@1e88685f5dde: no node (reposimplestore !)
  3 changeall
  2 changebagain
  1 merge
  0 moveb
  $ hg -R fixed verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 5 changesets, 5 total revisions

manifest -r 0

  $ hg -R fixed manifest -r 0
  a

manifest -r tip

  $ hg -R fixed manifest -r tip
  a
  c
  d