view tests/test-wireproto-command-filesdata.t @ 46607:e9901d01d135

revlog: add a mechanism to verify expected file position before appending

If someone uses `hg debuglocks`, or some non-hg process writes to the .hg
directory without respecting the locks, or if the repo's on a networked
filesystem, it's possible for the revlog code to write out corrupted data.

The form of this corruption can vary depending on what data was written and how
that happened. We are in the "networked filesystem" case (though I've had users
also do this to themselves with the "`hg debuglocks`" scenario), and most often
see this with the changelog. What ends up happening is we produce two items
(let's call them rev1 and rev2) in the .i file that have the same linkrev,
baserev, and offset into the .d file, while the data in the .d file is appended
properly. rev2's compressed_size is accurate for rev2, but when we go to
decompress the data in the .d file, we use the offset that's recorded in the
index file, which is the same as rev1, and attempt to decompress
rev2.compressed_size bytes of rev1's data. This usually does not succeed. :)

When using inline data, this also fails, though I haven't investigated why too
closely. This shows up as a "patch decode" error. I believe what's happening
there is that we're basically ignoring the offset field, getting the data
properly, but since baserev != rev, it thinks this is a delta based on rev
(instead of a full text) and can't actually apply it as such.

For now, I'm going to make this an optional component and default it to entirely
off. I may increase the default severity of this in the future, once I've
enabled it for my users and we gain more experience with it. Luckily, most of my
users have a versioned filesystem and can roll back to before the corruption has
been written, it's just a hassle to do so and not everyone knows how (so it's a
support burden). Users on other filesystems will not have that luxury, and this
can cause them to have a corrupted repository that they are unlikely to know how
to resolve, and they'll see this as a data-loss event. Refusing to create the
corruption is a much better user experience.

This mechanism is not perfect. There may be false-negatives (racy writes that
are not detected). There should not be any false-positives (non-racy writes that
are detected as such). This is not a mechanism that makes putting a repo on a
networked filesystem "safe" or "supported", just *less* likely to cause
corruption.

Differential Revision: https://phab.mercurial-scm.org/D9952

  $ . $TESTDIR/wireprotohelpers.sh

  $ hg init server
  $ enablehttpv2 server
  $ cd server
  $ cat > a << EOF
  > a0
  > 00000000000000000000000000000000000000
  > 11111111111111111111111111111111111111
  > EOF
  $ cat > b << EOF
  > b0
  > aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
  > bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
  > EOF
  $ mkdir -p dir0/child0 dir0/child1 dir1
  $ echo c0 > dir0/c
  $ echo d0 > dir0/d
  $ echo e0 > dir0/child0/e
  $ echo f0 > dir0/child1/f
  $ hg -q commit -A -m 'commit 0'

  $ echo a1 >> a
  $ echo d1 > dir0/d
  $ echo g0 > g
  $ echo h0 > h
  $ hg -q commit -A -m 'commit 1'
  $ echo f1 > dir0/child1/f
  $ echo i0 > dir0/i
  $ hg -q commit -A -m 'commit 2'

  $ hg -q up -r 0
  $ echo a2 >> a
  $ hg commit -m 'commit 3'
  created new head

Create multiple heads introducing the same file nodefile node

  $ hg -q up -r 0
  $ echo foo > dupe-file
  $ hg commit -Am 'dupe 1'
  adding dupe-file
  created new head
  $ hg -q up -r 0
  $ echo foo > dupe-file
  $ hg commit -Am 'dupe 2'
  adding dupe-file
  created new head

  $ hg log -G -T '{rev}:{node} {desc}\n'
  @  5:47fc30580911232cb264675b402819deddf6c6f0 dupe 2
  |
  | o  4:b16cce2967c1749ef4f4e3086a806cfbad8a3af7 dupe 1
  |/
  | o  3:476fbf122cd82f6726f0191ff146f67140946abc commit 3
  |/
  | o  2:b91c03cbba3519ab149b6cd0a0afbdb5cf1b5c8a commit 2
  | |
  | o  1:5b0b1a23577e205ea240e39c9704e28d7697cbd8 commit 1
  |/
  o  0:6e875ff18c227659ad6143bb3580c65700734884 commit 0
  

  $ hg serve -p $HGPORT -d --pid-file hg.pid -E error.log
  $ cat hg.pid > $DAEMON_PIDS

Missing arguments is an error

  $ sendhttpv2peer << EOF
  > command filesdata
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  abort: missing required arguments: revisions
  [255]

Bad pattern to pathfilter is rejected

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >          b'type': b'changesetexplicit',
  >          b'nodes': [
  >              b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >          ]}]
  >     pathfilter eval:{b'include': [b'bad:foo']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  abort: include pattern must begin with `path:` or `rootfilesin:`; got bad:foo
  [255]

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     pathfilter eval:{b'exclude': [b'glob:foo']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  abort: exclude pattern must begin with `path:` or `rootfilesin:`; got glob:foo
  [255]

Fetching a single changeset without parents fetches all files

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 8,
      b'totalpaths': 8
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2'
    },
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01'
    },
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4'
    },
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 1
    },
    {
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4'
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    }
  ]

Fetching a single changeset saying parents data is available fetches just new files

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     haveparents eval:True
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 4,
      b'totalpaths': 4
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    }
  ]

A path filter for a sub-directory is honored

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     haveparents eval:True
  >     pathfilter eval:{b'include': [b'path:dir0']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 1,
      b'totalpaths': 1
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    }
  ]

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     haveparents eval:True
  >     pathfilter eval:{b'exclude': [b'path:a', b'path:g']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 2,
      b'totalpaths': 2
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    }
  ]

Requesting multiple changeset nodes without haveparents sends all data for both

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >             b'\xb9\x1c\x03\xcb\xba\x35\x19\xab\x14\x9b\x6c\xd0\xa0\xaf\xbd\xb5\xcf\x1b\x5c\x8a',
  >         ]}]
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 10,
      b'totalpaths': 9
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2'
    },
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01'
    },
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4'
    },
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 2
    },
    {
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4'
    },
    {
      b'node': b'(\xc7v\xae\x08\xd0\xd5^\xb4\x06H\xb4\x01\xb9\x0f\xf5DH4\x8e'
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    {
      b'path': b'dir0/i',
      b'totalitems': 1
    },
    {
      b'node': b'\xd7t\xb5\x80Jq\xfd1\xe1\xae\x05\xea\x8e2\xdd\x9b\xa3\xd8S\xd7'
    },
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    }
  ]

Requesting multiple changeset nodes with haveparents sends incremental data for both

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >             b'\xb9\x1c\x03\xcb\xba\x35\x19\xab\x14\x9b\x6c\xd0\xa0\xaf\xbd\xb5\xcf\x1b\x5c\x8a',
  >         ]}]
  >     haveparents eval:True
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 6,
      b'totalpaths': 6
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 1
    },
    {
      b'node': b'(\xc7v\xae\x08\xd0\xd5^\xb4\x06H\xb4\x01\xb9\x0f\xf5DH4\x8e'
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    {
      b'path': b'dir0/i',
      b'totalitems': 1
    },
    {
      b'node': b'\xd7t\xb5\x80Jq\xfd1\xe1\xae\x05\xea\x8e2\xdd\x9b\xa3\xd8S\xd7'
    },
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    }
  ]

Requesting parents works

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     fields eval:[b'parents']
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 8,
      b'totalpaths': 8
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11',
      b'parents': [
        b'd\x9d\x14\x9d\xf4=\x83\x88%#\xb7\xfb\x1ej:\xf6\xf1\x90{9',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2',
      b'parents': [
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01',
      b'parents': [
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4',
      b'parents': [
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 1
    },
    {
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4',
      b'parents': [
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G',
      b'parents': [
        b'S\x82\x06\xdc\x97\x1eR\x15@\xd6\x84:\xbf\xe6\xd1`2\xf6\xd4&',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c',
      b'parents': [
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K',
      b'parents': [
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00',
        b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'
      ]
    }
  ]

Requesting revision data works
(haveparents defaults to False, so fulltext is emitted)

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     fields eval:[b'revision']
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 8,
      b'totalpaths': 8
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          84
        ]
      ],
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    b'a0\n00000000000000000000000000000000000000\n11111111111111111111111111111111111111\na1\n',
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          81
        ]
      ],
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2'
    },
    b'b0\naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\nbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n',
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01'
    },
    b'c0\n',
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4'
    },
    b'e0\n',
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4'
    },
    b'f0\n',
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    b'd1\n',
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    b'g0\n',
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    },
    b'h0\n'
  ]

haveparents=False should be same as above

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     fields eval:[b'revision']
  >     haveparents eval:False
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 8,
      b'totalpaths': 8
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          84
        ]
      ],
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    b'a0\n00000000000000000000000000000000000000\n11111111111111111111111111111111111111\na1\n',
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          81
        ]
      ],
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2'
    },
    b'b0\naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\nbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n',
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01'
    },
    b'c0\n',
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4'
    },
    b'e0\n',
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4'
    },
    b'f0\n',
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    b'd1\n',
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    b'g0\n',
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    },
    b'h0\n'
  ]

haveparents=True should emit a delta

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >         ]}]
  >     fields eval:[b'revision']
  >     haveparents eval:True
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 4,
      b'totalpaths': 4
    },
    {
      b'path': b'a',
      b'totalitems': 1
    },
    {
      b'deltabasenode': b'd\x9d\x14\x9d\xf4=\x83\x88%#\xb7\xfb\x1ej:\xf6\xf1\x90{9',
      b'fieldsfollowing': [
        [
          b'delta',
          15
        ]
      ],
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    b'\x00\x00\x00Q\x00\x00\x00Q\x00\x00\x00\x03a1\n',
    {
      b'path': b'dir0/d',
      b'totalitems': 1
    },
    {
      b'deltabasenode': b'S\x82\x06\xdc\x97\x1eR\x15@\xd6\x84:\xbf\xe6\xd1`2\xf6\xd4&',
      b'fieldsfollowing': [
        [
          b'delta',
          15
        ]
      ],
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03d1\n',
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    b'g0\n',
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    },
    b'h0\n'
  ]

Requesting multiple revisions works
(first revision is a fulltext since haveparents=False by default)

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x6e\x87\x5f\xf1\x8c\x22\x76\x59\xad\x61\x43\xbb\x35\x80\xc6\x57\x00\x73\x48\x84',
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >             b'\xb9\x1c\x03\xcb\xba\x35\x19\xab\x14\x9b\x6c\xd0\xa0\xaf\xbd\xb5\xcf\x1b\x5c\x8a',
  >         ]}]
  >     fields eval:[b'revision']
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 12,
      b'totalpaths': 9
    },
    {
      b'path': b'a',
      b'totalitems': 2
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          81
        ]
      ],
      b'node': b'd\x9d\x14\x9d\xf4=\x83\x88%#\xb7\xfb\x1ej:\xf6\xf1\x90{9'
    },
    b'a0\n00000000000000000000000000000000000000\n11111111111111111111111111111111111111\n',
    {
      b'deltabasenode': b'd\x9d\x14\x9d\xf4=\x83\x88%#\xb7\xfb\x1ej:\xf6\xf1\x90{9',
      b'fieldsfollowing': [
        [
          b'delta',
          15
        ]
      ],
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    b'\x00\x00\x00Q\x00\x00\x00Q\x00\x00\x00\x03a1\n',
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          81
        ]
      ],
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2'
    },
    b'b0\naaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\nbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb\n',
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01'
    },
    b'c0\n',
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4'
    },
    b'e0\n',
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 2
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4'
    },
    b'f0\n',
    {
      b'deltabasenode': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4',
      b'fieldsfollowing': [
        [
          b'delta',
          15
        ]
      ],
      b'node': b'(\xc7v\xae\x08\xd0\xd5^\xb4\x06H\xb4\x01\xb9\x0f\xf5DH4\x8e'
    },
    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03f1\n',
    {
      b'path': b'dir0/d',
      b'totalitems': 2
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'S\x82\x06\xdc\x97\x1eR\x15@\xd6\x84:\xbf\xe6\xd1`2\xf6\xd4&'
    },
    b'd0\n',
    {
      b'deltabasenode': b'S\x82\x06\xdc\x97\x1eR\x15@\xd6\x84:\xbf\xe6\xd1`2\xf6\xd4&',
      b'fieldsfollowing': [
        [
          b'delta',
          15
        ]
      ],
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    b'\x00\x00\x00\x00\x00\x00\x00\x03\x00\x00\x00\x03d1\n',
    {
      b'path': b'dir0/i',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xd7t\xb5\x80Jq\xfd1\xe1\xae\x05\xea\x8e2\xdd\x9b\xa3\xd8S\xd7'
    },
    b'i0\n',
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    b'g0\n',
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'fieldsfollowing': [
        [
          b'revision',
          3
        ]
      ],
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    },
    b'h0\n'
  ]

Requesting linknode field works

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x6e\x87\x5f\xf1\x8c\x22\x76\x59\xad\x61\x43\xbb\x35\x80\xc6\x57\x00\x73\x48\x84',
  >             b'\x5b\x0b\x1a\x23\x57\x7e\x20\x5e\xa2\x40\xe3\x9c\x97\x04\xe2\x8d\x76\x97\xcb\xd8',
  >             b'\xb9\x1c\x03\xcb\xba\x35\x19\xab\x14\x9b\x6c\xd0\xa0\xaf\xbd\xb5\xcf\x1b\x5c\x8a',
  >         ]}]
  >     fields eval:[b'linknode']
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 12,
      b'totalpaths': 9
    },
    {
      b'path': b'a',
      b'totalitems': 2
    },
    {
      b'linknode': b'n\x87_\xf1\x8c"vY\xadaC\xbb5\x80\xc6W\x00sH\x84',
      b'node': b'd\x9d\x14\x9d\xf4=\x83\x88%#\xb7\xfb\x1ej:\xf6\xf1\x90{9'
    },
    {
      b'linknode': b'[\x0b\x1a#W~ ^\xa2@\xe3\x9c\x97\x04\xe2\x8dv\x97\xcb\xd8',
      b'node': b'\n\x862\x1f\x13y\xd1\xa9\xec\xd0W\x9a"\x97z\xf7\xa5\xac\xaf\x11'
    },
    {
      b'path': b'b',
      b'totalitems': 1
    },
    {
      b'linknode': b'n\x87_\xf1\x8c"vY\xadaC\xbb5\x80\xc6W\x00sH\x84',
      b'node': b'\x88\xbac\xb8\xd8\xc6 :\xc6z\xc9\x98\xac\xd9\x17K\xf7\x05!\xb2'
    },
    {
      b'path': b'dir0/c',
      b'totalitems': 1
    },
    {
      b'linknode': b'n\x87_\xf1\x8c"vY\xadaC\xbb5\x80\xc6W\x00sH\x84',
      b'node': b'\x91DE4j\x0c\xa0b\x9b\xd4|\xeb]\xfe\x07\xe4\xd4\xcf%\x01'
    },
    {
      b'path': b'dir0/child0/e',
      b'totalitems': 1
    },
    {
      b'linknode': b'n\x87_\xf1\x8c"vY\xadaC\xbb5\x80\xc6W\x00sH\x84',
      b'node': b'\xbb\xbal\x06\xb3\x0fD=4\xff\x84\x1b\xc9\x85\xc4\xd0\x82|k\xe4'
    },
    {
      b'path': b'dir0/child1/f',
      b'totalitems': 2
    },
    {
      b'linknode': b'n\x87_\xf1\x8c"vY\xadaC\xbb5\x80\xc6W\x00sH\x84',
      b'node': b'\x12\xfc}\xcdw;Z\n\x92\x9c\xe1\x95"\x80\x83\xc6\xdd\xc9\xce\xc4'
    },
    {
      b'linknode': b'\xb9\x1c\x03\xcb\xba5\x19\xab\x14\x9bl\xd0\xa0\xaf\xbd\xb5\xcf\x1b\\\x8a',
      b'node': b'(\xc7v\xae\x08\xd0\xd5^\xb4\x06H\xb4\x01\xb9\x0f\xf5DH4\x8e'
    },
    {
      b'path': b'dir0/d',
      b'totalitems': 2
    },
    {
      b'linknode': b'n\x87_\xf1\x8c"vY\xadaC\xbb5\x80\xc6W\x00sH\x84',
      b'node': b'S\x82\x06\xdc\x97\x1eR\x15@\xd6\x84:\xbf\xe6\xd1`2\xf6\xd4&'
    },
    {
      b'linknode': b'[\x0b\x1a#W~ ^\xa2@\xe3\x9c\x97\x04\xe2\x8dv\x97\xcb\xd8',
      b'node': b'\x93\x88)\xad\x01R}2\xba\x06_\x81#6\xfe\xc7\x9d\xdd9G'
    },
    {
      b'path': b'dir0/i',
      b'totalitems': 1
    },
    {
      b'linknode': b'\xb9\x1c\x03\xcb\xba5\x19\xab\x14\x9bl\xd0\xa0\xaf\xbd\xb5\xcf\x1b\\\x8a',
      b'node': b'\xd7t\xb5\x80Jq\xfd1\xe1\xae\x05\xea\x8e2\xdd\x9b\xa3\xd8S\xd7'
    },
    {
      b'path': b'g',
      b'totalitems': 1
    },
    {
      b'linknode': b'[\x0b\x1a#W~ ^\xa2@\xe3\x9c\x97\x04\xe2\x8dv\x97\xcb\xd8',
      b'node': b'\xde\xca\xba5DFjI\x95r\xe9\x0f\xac\xe6\xfa\x0c!k\xba\x8c'
    },
    {
      b'path': b'h',
      b'totalitems': 1
    },
    {
      b'linknode': b'[\x0b\x1a#W~ ^\xa2@\xe3\x9c\x97\x04\xe2\x8dv\x97\xcb\xd8',
      b'node': b'\x03A\xfc\x84\x1b\xb5\xb4\xba\x93\xb2mM\xdaa\xf7y6]\xb3K'
    }
  ]

Test behavior where a file node is introduced in 2 DAG heads

Request for changeset introducing filenode returns linknode as self

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\xb1\x6c\xce\x29\x67\xc1\x74\x9e\xf4\xf4\xe3\x08\x6a\x80\x6c\xfb\xad\x8a\x3a\xf7',
  >         ]}]
  >     fields eval:[b'linknode']
  >     pathfilter eval:{b'include': [b'path:dupe-file']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 1,
      b'totalpaths': 1
    },
    {
      b'path': b'dupe-file',
      b'totalitems': 1
    },
    {
      b'linknode': b'\xb1l\xce)g\xc1t\x9e\xf4\xf4\xe3\x08j\x80l\xfb\xad\x8a:\xf7',
      b'node': b'.\xd2\xa3\x91*\x0b$P C\xea\xe8N\xe4\xb2y\xc1\x8b\x90\xdd'
    }
  ]

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\xb1\x6c\xce\x29\x67\xc1\x74\x9e\xf4\xf4\xe3\x08\x6a\x80\x6c\xfb\xad\x8a\x3a\xf7',
  >         ]}]
  >     fields eval:[b'linknode']
  >     haveparents eval:True
  >     pathfilter eval:{b'include': [b'path:dupe-file']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 1,
      b'totalpaths': 1
    },
    {
      b'path': b'dupe-file',
      b'totalitems': 1
    },
    {
      b'linknode': b'\xb1l\xce)g\xc1t\x9e\xf4\xf4\xe3\x08j\x80l\xfb\xad\x8a:\xf7',
      b'node': b'.\xd2\xa3\x91*\x0b$P C\xea\xe8N\xe4\xb2y\xc1\x8b\x90\xdd'
    }
  ]

Request for changeset where recorded linknode isn't in DAG ancestry will get
rewritten accordingly

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x47\xfc\x30\x58\x09\x11\x23\x2c\xb2\x64\x67\x5b\x40\x28\x19\xde\xdd\xf6\xc6\xf0',
  >         ]}]
  >     fields eval:[b'linknode']
  >     pathfilter eval:{b'include': [b'path:dupe-file']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 1,
      b'totalpaths': 1
    },
    {
      b'path': b'dupe-file',
      b'totalitems': 1
    },
    {
      b'linknode': b'G\xfc0X\t\x11#,\xb2dg[@(\x19\xde\xdd\xf6\xc6\xf0',
      b'node': b'.\xd2\xa3\x91*\x0b$P C\xea\xe8N\xe4\xb2y\xc1\x8b\x90\xdd'
    }
  ]

  $ sendhttpv2peer << EOF
  > command filesdata
  >     revisions eval:[{
  >         b'type': b'changesetexplicit',
  >         b'nodes': [
  >             b'\x47\xfc\x30\x58\x09\x11\x23\x2c\xb2\x64\x67\x5b\x40\x28\x19\xde\xdd\xf6\xc6\xf0',
  >         ]}]
  >     fields eval:[b'linknode']
  >     haveparents eval:True
  >     pathfilter eval:{b'include': [b'path:dupe-file']}
  > EOF
  creating http peer for wire protocol version 2
  sending filesdata command
  response: gen[
    {
      b'totalitems': 1,
      b'totalpaths': 1
    },
    {
      b'path': b'dupe-file',
      b'totalitems': 1
    },
    {
      b'linknode': b'G\xfc0X\t\x11#,\xb2dg[@(\x19\xde\xdd\xf6\xc6\xf0',
      b'node': b'.\xd2\xa3\x91*\x0b$P C\xea\xe8N\xe4\xb2y\xc1\x8b\x90\xdd'
    }
  ]

  $ cat error.log