tests/test-remotefilelog-http.t

interfaces: introduce and use a protocol class for the `mpatch` module

See f2832de2a46c for details when this was done for the `bdiff` module.

Two things worth pointing out-

  1) The `cffi` module "inherits" the `pure` implementation of `patchedsize()`
     because of its wildcard import.
  2) It's odd that the `mpatchError` lives in both `pure` and `cext` modules.

I initially thought to move the exception into the new class, and make the
existing class name an alias to the class in the new location, but the exception
is created in C code by the `cext` module, so that won't work.  I don't think a
protocol class is approriate, because there's nothing special about the class to
distinguish from any other `Exception`.  Fortunately, nobody is catching this
exception in core, so we can kick the can down the road.

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ echo y > y
  $ hg commit -qAm x
  $ hg serve -p $HGPORT -d --pid-file=../hg1.pid -E ../error.log -A ../access.log

Build a query string for later use:
  $ GET=`hg debugdata -m 0 | "$PYTHON" -c \
  > 'import sys ; print([("?cmd=x_rfl_getfile&file=%s&node=%s" % tuple(s.split("\0"))) for s in sys.stdin.read().splitlines()][0])'`

  $ cd ..
  $ cat hg1.pid >> $DAEMON_PIDS

  $ hgcloneshallow http://localhost:$HGPORT/ shallow -q
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

  $ grep getfile access.log
  * "GET /?cmd=batch HTTP/1.1" 200 - x-hgarg-1:cmds=x_rfl_getfile+*node%3D1406e74118627694268417491f018a4a883152f0* (glob)

Clear filenode cache so we can test fetching with a modified batch size
  $ rm -r $TESTTMP/hgcache
Now do a fetch with a large batch size so we're sure it works
  $ hgcloneshallow http://localhost:$HGPORT/ shallow-large-batch \
  >    --config remotefilelog.batchsize=1000 -q
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

The 'remotefilelog' capability should *not* be exported over http(s),
as the getfile method it offers doesn't work with http.
  $ get-with-headers.py localhost:$HGPORT '?cmd=capabilities' | grep lookup | identifyrflcaps
  x_rfl_getfile
  x_rfl_getflogheads

  $ get-with-headers.py localhost:$HGPORT '?cmd=hello' | grep lookup | identifyrflcaps
  x_rfl_getfile
  x_rfl_getflogheads

  $ get-with-headers.py localhost:$HGPORT '?cmd=this-command-does-not-exist' | head -n 1
  400 no such method: this-command-does-not-exist
  $ get-with-headers.py localhost:$HGPORT '?cmd=x_rfl_getfiles' | head -n 1
  400 no such method: x_rfl_getfiles

Verify serving from a shallow clone doesn't allow for remotefile
fetches. This also serves to test the error handling for our batchable
getfile RPC.

  $ cd shallow
  $ hg serve -p $HGPORT1 -d --pid-file=../hg2.pid -E ../error2.log
  $ cd ..
  $ cat hg2.pid >> $DAEMON_PIDS

This GET should work, because this server is serving master, which is
a full clone.

  $ get-with-headers.py localhost:$HGPORT "$GET"
  200 Script output follows
  
  0\x00x\x9c3b\xa8\xe0\x12a{\xee(\x91T6E\xadE\xdcS\x9e\xb1\xcb\xab\xc30\xe8\x03\x03\x91 \xe4\xc6\xfb\x99J,\x17\x0c\x9f-\xcb\xfcR7c\xf3c\x97r\xbb\x10\x06\x00\x96m\x121 (no-eol) (esc)

This GET should fail using the in-band signalling mechanism, because
it's not a full clone. Note that it's also plausible for servers to
refuse to serve file contents for other reasons, like the file
contents not being visible to the current user.

  $ get-with-headers.py localhost:$HGPORT1 "$GET"
  200 Script output follows
  
  1\x00cannot fetch remote files from shallow repo (no-eol) (esc)

Clones should work with httppostargs turned on

  $ cd master
  $ hg --config experimental.httppostargs=1 serve -p $HGPORT2 -d --pid-file=../hg3.pid -E ../error3.log

  $ cd ..
  $ cat hg3.pid >> $DAEMON_PIDS

Clear filenode cache so we can test fetching with a modified batch size
  $ rm -r $TESTTMP/hgcache

  $ hgcloneshallow http://localhost:$HGPORT2/ shallow-postargs -q
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

All error logs should be empty:
  $ cat error.log
  $ cat error2.log
  $ cat error3.log