tests/test-lfs-serve.t

debugcommands: introduce actions to perform deterministic reads

"readavailable" is useful as a debugging device to see what data is
available on a pipe. But the mechanism isn't deterministic because
what's available on a pipe is highly conditional on timing, system
load, OS behavior, etc. This makes it not suitable for tests.

We introduce "ereadline," "read," and "eread" for performing
deterministic I/O operations (at least on blocking file descriptors).

We stop short of converting existing consumers of "readavailable"
in tests because we're working out race conditions and deadlocks
on Windows. But the goal is to eventually move tests away from
"readavailable" to these new APIs.

Differential Revision: https://phab.mercurial-scm.org/D2720

#testcases lfsremote-on lfsremote-off
#require serve

This test splits `hg serve` with and without using the extension into separate
tests cases.  The tests are broken down as follows, where "LFS"/"No-LFS"
indicates whether or not there are commits that use an LFS file, and "D"/"E"
indicates whether or not the extension is loaded.  The "X" cases are not tested
individually, because the lfs requirement causes the process to bail early if
the extension is disabled.

.                        Server
.
.                    No-LFS        LFS
.            +----------------------------+
.            |   ||  D  |  E  |  D  |  E  |
.            |---++=======================|
.  C         | D || N/A | #1  |  X  | #4  |
.  l    No   +---++-----------------------|
.  i    LFS  | E || #2  | #2  |  X  | #5  |
.  e         +---++-----------------------|
.  n         | D ||  X  |  X  |  X  |  X  |
.  t    LFS  |---++-----------------------|
.            | E || #3  | #3  |  X  | #6  |
.            |---++-----------------------+

  $ hg init server
  $ SERVER_REQUIRES="$TESTTMP/server/.hg/requires"

Skip the experimental.changegroup3=True config.  Failure to agree on this comes
first, and causes a "ValueError: no common changegroup version" or "abort:
HTTP Error 500: Internal Server Error", if the extension is only loaded on one
side.  If that *is* enabled, the subsequent failure is "abort: missing processor
for flag '0x2000'!" if the extension is only loaded on one side (possibly also
masked by the Internal Server Error message).
  $ cat >> $HGRCPATH <<EOF
  > [lfs]
  > url=file:$TESTTMP/dummy-remote/
  > threshold=10
  > [web]
  > allow_push=*
  > push_ssl=False
  > EOF

#if lfsremote-on
  $ hg --config extensions.lfs= -R server \
  >    serve -p $HGPORT -d --pid-file=hg.pid --errorlog=$TESTTMP/errors.log
#else
  $ hg --config extensions.lfs=! -R server \
  >    serve -p $HGPORT -d --pid-file=hg.pid --errorlog=$TESTTMP/errors.log
#endif

  $ cat hg.pid >> $DAEMON_PIDS
  $ hg clone -q http://localhost:$HGPORT client
  $ grep 'lfs' client/.hg/requires $SERVER_REQUIRES
  [1]

--------------------------------------------------------------------------------
Case #1: client with non-lfs content and the extension disabled; server with
non-lfs content, and the extension enabled.

  $ cd client
  $ echo 'non-lfs' > nonlfs.txt
  $ hg ci -Aqm 'non-lfs'
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  [1]

#if lfsremote-on

  $ hg push -q
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  [1]

  $ hg clone -q http://localhost:$HGPORT $TESTTMP/client1_clone
  $ grep 'lfs' $TESTTMP/client1_clone/.hg/requires $SERVER_REQUIRES
  [1]

  $ hg init $TESTTMP/client1_pull
  $ hg -R $TESTTMP/client1_pull pull -q http://localhost:$HGPORT
  $ grep 'lfs' $TESTTMP/client1_pull/.hg/requires $SERVER_REQUIRES
  [1]

  $ hg identify http://localhost:$HGPORT
  d437e1d24fbd

#endif

--------------------------------------------------------------------------------
Case #2: client with non-lfs content and the extension enabled; server with
non-lfs content, and the extension state controlled by #testcases.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > lfs =
  > EOF
  $ echo 'non-lfs' > nonlfs2.txt
  $ hg ci -Aqm 'non-lfs file with lfs client'

Since no lfs content has been added yet, the push is allowed, even when the
extension is not enabled remotely.

  $ hg push -q
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  [1]

  $ hg clone -q http://localhost:$HGPORT $TESTTMP/client2_clone
  $ grep 'lfs' $TESTTMP/client2_clone/.hg/requires $SERVER_REQUIRES
  [1]

  $ hg init $TESTTMP/client2_pull
  $ hg -R $TESTTMP/client2_pull pull -q http://localhost:$HGPORT
  $ grep 'lfs' $TESTTMP/client2_pull/.hg/requires $SERVER_REQUIRES
  [1]

  $ hg identify http://localhost:$HGPORT
  1477875038c6

--------------------------------------------------------------------------------
Case #3: client with lfs content and the extension enabled; server with
non-lfs content, and the extension state controlled by #testcases.  The server
should have an 'lfs' requirement after it picks up its first commit with a blob.

  $ echo 'this is a big lfs file' > lfs.bin
  $ hg ci -Aqm 'lfs'
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  .hg/requires:lfs

#if lfsremote-off
  $ hg push -q
  abort: required features are not supported in the destination: lfs
  (enable the lfs extension on the server)
  [255]
#else
  $ hg push -q
#endif
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  .hg/requires:lfs
  $TESTTMP/server/.hg/requires:lfs (lfsremote-on !)

  $ hg clone -q http://localhost:$HGPORT $TESTTMP/client3_clone
  $ grep 'lfs' $TESTTMP/client3_clone/.hg/requires $SERVER_REQUIRES || true
  $TESTTMP/client3_clone/.hg/requires:lfs (lfsremote-on !)
  $TESTTMP/server/.hg/requires:lfs (lfsremote-on !)

  $ hg init $TESTTMP/client3_pull
  $ hg -R $TESTTMP/client3_pull pull -q http://localhost:$HGPORT
  $ grep 'lfs' $TESTTMP/client3_pull/.hg/requires $SERVER_REQUIRES || true
  $TESTTMP/client3_pull/.hg/requires:lfs (lfsremote-on !)
  $TESTTMP/server/.hg/requires:lfs (lfsremote-on !)

The difference here is the push failed above when the extension isn't
enabled on the server.
  $ hg identify http://localhost:$HGPORT
  8374dc4052cb (lfsremote-on !)
  1477875038c6 (lfsremote-off !)

Don't bother testing the lfsremote-off cases- the server won't be able
to launch if there's lfs content and the extension is disabled.

#if lfsremote-on

--------------------------------------------------------------------------------
Case #4: client with non-lfs content and the extension disabled; server with
lfs content, and the extension enabled.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > lfs = !
  > EOF

  $ hg init $TESTTMP/client4
  $ cd $TESTTMP/client4
  $ cat >> .hg/hgrc <<EOF
  > [paths]
  > default = http://localhost:$HGPORT
  > EOF
  $ echo 'non-lfs' > nonlfs2.txt
  $ hg ci -Aqm 'non-lfs'
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  $TESTTMP/server/.hg/requires:lfs

  $ hg push -q --force
  warning: repository is unrelated
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  $TESTTMP/server/.hg/requires:lfs

TODO: fail more gracefully.

  $ hg clone -q http://localhost:$HGPORT $TESTTMP/client4_clone
  abort: HTTP Error 500: Internal Server Error
  [255]
  $ grep 'lfs' $TESTTMP/client4_clone/.hg/requires $SERVER_REQUIRES
  grep: $TESTTMP/client4_clone/.hg/requires: $ENOENT$
  $TESTTMP/server/.hg/requires:lfs
  [2]

TODO: fail more gracefully.

  $ hg init $TESTTMP/client4_pull
  $ hg -R $TESTTMP/client4_pull pull -q http://localhost:$HGPORT
  abort: HTTP Error 500: Internal Server Error
  [255]
  $ grep 'lfs' $TESTTMP/client4_pull/.hg/requires $SERVER_REQUIRES
  $TESTTMP/server/.hg/requires:lfs

  $ hg identify http://localhost:$HGPORT
  03b080fa9d93

--------------------------------------------------------------------------------
Case #5: client with non-lfs content and the extension enabled; server with
lfs content, and the extension enabled.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > lfs =
  > EOF
  $ echo 'non-lfs' > nonlfs3.txt
  $ hg ci -Aqm 'non-lfs file with lfs client'

  $ hg push -q
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  $TESTTMP/server/.hg/requires:lfs

  $ hg clone -q http://localhost:$HGPORT $TESTTMP/client5_clone
  $ grep 'lfs' $TESTTMP/client5_clone/.hg/requires $SERVER_REQUIRES
  $TESTTMP/client5_clone/.hg/requires:lfs
  $TESTTMP/server/.hg/requires:lfs

  $ hg init $TESTTMP/client5_pull
  $ hg -R $TESTTMP/client5_pull pull -q http://localhost:$HGPORT
  $ grep 'lfs' $TESTTMP/client5_pull/.hg/requires $SERVER_REQUIRES
  $TESTTMP/client5_pull/.hg/requires:lfs
  $TESTTMP/server/.hg/requires:lfs

  $ hg identify http://localhost:$HGPORT
  c729025cc5e3

--------------------------------------------------------------------------------
Case #6: client with lfs content and the extension enabled; server with
lfs content, and the extension enabled.

  $ echo 'this is another lfs file' > lfs2.txt
  $ hg ci -Aqm 'lfs file with lfs client'

  $ hg push -q
  $ grep 'lfs' .hg/requires $SERVER_REQUIRES
  .hg/requires:lfs
  $TESTTMP/server/.hg/requires:lfs

  $ hg clone -q http://localhost:$HGPORT $TESTTMP/client6_clone
  $ grep 'lfs' $TESTTMP/client6_clone/.hg/requires $SERVER_REQUIRES
  $TESTTMP/client6_clone/.hg/requires:lfs
  $TESTTMP/server/.hg/requires:lfs

  $ hg init $TESTTMP/client6_pull
  $ hg -R $TESTTMP/client6_pull pull -q http://localhost:$HGPORT
  $ grep 'lfs' $TESTTMP/client6_pull/.hg/requires $SERVER_REQUIRES
  $TESTTMP/client6_pull/.hg/requires:lfs
  $TESTTMP/server/.hg/requires:lfs

  $ hg identify http://localhost:$HGPORT
  d3b84d50eacb

--------------------------------------------------------------------------------
Misc: process dies early if a requirement exists and the extension is disabled

  $ hg --config extensions.lfs=! summary
  abort: repository requires features unknown to this Mercurial: lfs!
  (see https://mercurial-scm.org/wiki/MissingRequirement for more information)
  [255]

#endif

  $ $PYTHON $TESTDIR/killdaemons.py $DAEMON_PIDS

#if lfsremote-on
  $ cat $TESTTMP/errors.log | grep '^[A-Z]'
  Traceback (most recent call last):
  ValueError: no common changegroup version
  Traceback (most recent call last):
  ValueError: no common changegroup version
#else
  $ cat $TESTTMP/errors.log
#endif