view tests/test-narrow-shallow.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"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [narrow]
  > serveellipses=True
  > EOF
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo $x > "f$x"
  >   hg add "f$x"
  > done
  $ hg commit -m "Add root files"
  $ mkdir d1 d2
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo d1/$x > "d1/f$x"
  >   hg add "d1/f$x"
  >   echo d2/$x > "d2/f$x"
  >   hg add "d2/f$x"
  > done
  $ hg commit -m "Add d1 and d2"
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo f$x rev2 > "f$x"
  >   echo d1/f$x rev2 > "d1/f$x"
  >   echo d2/f$x rev2 > "d2/f$x"
  >   hg commit -m "Commit rev2 of f$x, d1/f$x, d2/f$x"
  > done
  $ cd ..

narrow and shallow clone the d2 directory

  $ hg clone --narrow ssh://user@dummy/master shallow --include "d2" --depth 2
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 13 changes to 10 files
  new changesets *:* (glob)
  updating to branch default
  10 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd shallow
  $ hg log -T '{rev}{if(ellipsis,"...")}: {desc}\n'
  3: Commit rev2 of f10, d1/f10, d2/f10
  2: Commit rev2 of f9, d1/f9, d2/f9
  1: Commit rev2 of f8, d1/f8, d2/f8
  0...: Commit rev2 of f7, d1/f7, d2/f7
  $ hg update 0
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat d2/f7 d2/f8
  d2/f7 rev2
  d2/8

  $ cd ..

change every upstream file once

  $ cd master
  $ for x in `$TESTDIR/seq.py 10`
  > do
  >   echo f$x rev3 > "f$x"
  >   echo d1/f$x rev3 > "d1/f$x"
  >   echo d2/f$x rev3 > "d2/f$x"
  >   hg commit -m "Commit rev3 of f$x, d1/f$x, d2/f$x"
  > done
  $ cd ..

pull new changes with --depth specified. There were 10 changes to the d2
directory but the shallow pull should only fetch 3.

  $ cd shallow
  $ hg pull --depth 2
  pulling from ssh://user@dummy/master
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 4 changesets with 10 changes to 10 files
  new changesets *:* (glob)
  (run 'hg update' to get a working copy)
  $ hg log -T '{rev}{if(ellipsis,"...")}: {desc}\n'
  7: Commit rev3 of f10, d1/f10, d2/f10
  6: Commit rev3 of f9, d1/f9, d2/f9
  5: Commit rev3 of f8, d1/f8, d2/f8
  4...: Commit rev3 of f7, d1/f7, d2/f7
  3: Commit rev2 of f10, d1/f10, d2/f10
  2: Commit rev2 of f9, d1/f9, d2/f9
  1: Commit rev2 of f8, d1/f8, d2/f8
  0...: Commit rev2 of f7, d1/f7, d2/f7
  $ hg update 4
  merging d2/f1
  merging d2/f2
  merging d2/f3
  merging d2/f4
  merging d2/f5
  merging d2/f6
  merging d2/f7
  3 files updated, 7 files merged, 0 files removed, 0 files unresolved
  $ cat d2/f7 d2/f8
  d2/f7 rev3
  d2/f8 rev2
  $ hg update 7
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat d2/f10
  d2/f10 rev3

  $ cd ..

cannot clone with zero or negative depth

  $ hg clone --narrow ssh://user@dummy/master bad --include "d2" --depth 0
  requesting all changes
  remote: abort: depth must be positive, got 0
  abort: pull failed on remote
  [255]
  $ hg clone --narrow ssh://user@dummy/master bad --include "d2" --depth -1
  requesting all changes
  remote: abort: depth must be positive, got -1
  abort: pull failed on remote
  [255]