view tests/test-narrow-exchange.t @ 37048:fc5e261915b9

wireproto: require POST for all HTTPv2 requests

Wire protocol version 1 transfers argument data via request
headers by default. This has historically caused problems because
servers institute limits on the length of individual HTTP headers
as well as the total size of all request headers. Mercurial servers
can advertise the maximum length of an individual header. But
there's no guarantee any intermediate HTTP agents will accept
headers up to that length.

In the existing wire protocol, server operators typically also
key off the HTTP request method to implement authentication.
For example, GET requests translate to read-only requests and
can be allowed. But read-write commands must use POST and require
authentication. This has typically worked because the only wire
protocol commands that use POST modify the repo (e.g. the
"unbundle" command).

There is an experimental feature to enable clients to transmit
argument data via POST request bodies. This is technically a
better and more robust solution. But we can't enable it by default
because of servers assuming POST means write access.

In version 2 of the wire protocol, the permissions of a request
are encoded in the URL. And with it being a new protocol in a new
URL space, we're not constrained by backwards compatibility
requirements.

This commit adopts the technically superior mechanism of using
HTTP request bodies to send argument data by requiring POST for
all commands. Strictly speaking, it may be possible to send
request bodies on GET requests. But my experience is that not all
HTTP stacks support this. POST pretty much always works. Using POST
for read-only operations does sacrifice some RESTful design
purity. But this API cares about practicality, not about being
in Roy T. Fielding's REST ivory tower.

There's a chance we may relax this restriction in the future. But
for now, I want to see how far we can get with a POST only API.

Differential Revision: https://phab.mercurial-scm.org/D2837

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

create full repo

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF

  $ mkdir inside
  $ echo 1 > inside/f
  $ mkdir inside2
  $ echo 1 > inside2/f
  $ mkdir outside
  $ echo 1 > outside/f
  $ hg ci -Aqm 'initial'

  $ echo 2 > inside/f
  $ hg ci -qm 'inside 2'

  $ echo 2 > inside2/f
  $ hg ci -qm 'inside2 2'

  $ echo 2 > outside/f
  $ hg ci -qm 'outside 2'

  $ cd ..

  $ hg clone --narrow ssh://user@dummy/master narrow --include inside
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 2 changes to 1 files
  new changesets *:* (glob)
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg clone --narrow ssh://user@dummy/master narrow2 --include inside --include inside2
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 4 changes to 2 files
  new changesets *:* (glob)
  updating to branch default
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved

Can push to wider repo if change does not affect paths in wider repo that are
not also in narrower repo

  $ cd narrow
  $ echo 3 > inside/f
  $ hg ci -m 'inside 3'
  $ hg push ssh://user@dummy/narrow2
  pushing to ssh://user@dummy/narrow2
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files

Can push to narrower repo if change affects only paths within remote's
narrow spec

  $ cd ../narrow2
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF
  $ hg co -r 'desc("inside 3")'
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo 4 > inside/f
  $ hg ci -m 'inside 4'
  $ hg push ssh://user@dummy/narrow
  pushing to ssh://user@dummy/narrow
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 1 changes to 1 files

Can push to narrow repo if change affects only paths outside remote's
narrow spec

  $ echo 3 > inside2/f
  $ hg ci -m 'inside2 3'
TODO: this should be successful
  $ hg push ssh://user@dummy/narrow
  pushing to ssh://user@dummy/narrow
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: transaction abort!
  remote: rollback completed
  remote: abort: data/inside2/f.i@4a1aa07735e6: unknown parent!
  abort: stream ended unexpectedly (got 0 bytes, expected 4)
  [255]

Can pull from wider repo if change affects only paths outside remote's
narrow spec
  $ echo 4 > inside2/f
  $ hg ci -m 'inside2 4'
  $ hg log -G -T '{rev} {node|short} {files}\n'
  @  7 d78a96df731d inside2/f
  |
  o  6 8c26f5218962 inside2/f
  |
  o  5 ba3480e2f9de inside/f
  |
  o  4 4e5edd526618 inside/f
  |
  o  3 81e7e07b7ab0 outside/f
  |
  o  2 f3993b8c0c2b inside2/f
  |
  o  1 8cd66ca966b4 inside/f
  |
  o  0 c8057d6f53ab inside/f inside2/f outside/f
  
  $ cd ../narrow
  $ hg log -G -T '{rev} {node|short} {files}\n'
  o  4 ba3480e2f9de inside/f
  |
  @  3 4e5edd526618 inside/f
  |
  o  2 81e7e07b7ab0 outside/f
  |
  o  1 8cd66ca966b4 inside/f
  |
  o  0 c8057d6f53ab inside/f inside2/f outside/f
  
  $ hg pull ssh://user@dummy/narrow2
  pulling from ssh://user@dummy/narrow2
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets d78a96df731d
  (run 'hg update' to get a working copy)

Check that the resulting history is valid in the full repo

  $ cd ../narrow2
  $ hg push ssh://user@dummy/master
  pushing to ssh://user@dummy/master
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 4 changesets with 4 changes to 2 files
  $ cd ../master
  $ hg verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  3 files, 8 changesets, 10 total revisions

Can not push to wider repo if change affects paths in wider repo that are
not also in narrower repo
  $ cd ../master
  $ hg co -r 'desc("inside2 4")'
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo 5 > inside2/f
  $ hg ci -m 'inside2 5'
  $ hg log -G -T '{rev} {node|short} {files}\n'
  @  8 5970befb64ba inside2/f
  |
  o  7 d78a96df731d inside2/f
  |
  o  6 8c26f5218962 inside2/f
  |
  o  5 ba3480e2f9de inside/f
  |
  o  4 4e5edd526618 inside/f
  |
  o  3 81e7e07b7ab0 outside/f
  |
  o  2 f3993b8c0c2b inside2/f
  |
  o  1 8cd66ca966b4 inside/f
  |
  o  0 c8057d6f53ab inside/f inside2/f outside/f
  
  $ cd ../narrow
  $ hg pull
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 0 files
  new changesets * (glob)
  (run 'hg update' to get a working copy)
TODO: this should tell the user that their narrow clone does not have the
necessary content to be able to push to the target
  $ hg push ssh://user@dummy/narrow2
  pushing to ssh://user@dummy/narrow2
  searching for changes
  remote: adding changesets
  remote: adding manifests
  remote: adding file changes
  remote: added 1 changesets with 0 changes to 0 files