tests/test-pull-http.t

wireprotov2: client support for following content redirects

And with the server actually sending content redirects, it is finally
time to implement client support for following them!

When a redirect response is seen, we wait until all data for that
request has been received (it should be nearly immediate since no
data is expected to follow the redirect message). Then we use
a URL opener to make a request. We stuff that response into the
client handler and construct a new response object to track it.

When readdata() is called for servicing requests, we attempt to
read data from the first redirected response. During data reading,
data is processed similarly to as if it came from a frame payload.

The existing test for the functionality demonstrates the client
transparently following the redirect and obtaining the command
response data from an alternate URL!

There is still plenty of work to do here, including shoring up
testing. I'm not convinced things will work in the presence of
multiple redirect responses. And we don't yet implement support
for integrity verification or configuring server certificates
to validate the connection. But it's a start. And it should enable
us to start experimenting with "real" caches.

Differential Revision: https://phab.mercurial-scm.org/D4778

#if no-windows
For debugging: this is a pretty simple test that is a good candidate
for tracking down network-related bugs. Sometimes a command in this
hangs, so having showstack pre-loaded is sometimes helpful. This also
gives us a test that at least proves showstack can be loaded.
  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > showstack = $TESTDIR/../contrib/showstack.py
  > EOF
#endif

  $ hg init test
  $ cd test
  $ echo a > a
  $ hg ci -Ama
  adding a
  $ cd ..
  $ hg clone test test2
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cd test2
  $ echo a >> a
  $ hg ci -mb

Cloning with a password in the URL should not save the password in .hg/hgrc:

  $ hg serve -p $HGPORT -d --pid-file=hg.pid -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS
  $ hg clone http://foo:xyzzy@localhost:$HGPORT/ test3
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 1 files
  new changesets cb9a9f314b8b:ba677d0156c1
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ cat test3/.hg/hgrc
  # example repository config (see 'hg help config' for more info)
  [paths]
  default = http://foo@localhost:$HGPORT/
  
  # path aliases to other clones of this repo in URLs or filesystem paths
  # (see 'hg help config.paths' for more info)
  #
  # default:pushurl = ssh://[e-mail]/hg/jdoes-fork
  # my-fork         = ssh://[e-mail]/hg/jdoes-fork
  # my-clone        = /home/jdoe/jdoes-clone
  
  [ui]
  # name and email (local to this repository, optional), e.g.
  # username = Jane Doe <[e-mail]>
  $ killdaemons.py

expect error, cloning not allowed

  $ echo '[web]' > .hg/hgrc
  $ echo 'allowpull = false' >> .hg/hgrc
  $ hg serve -p $HGPORT -d --pid-file=hg.pid -E errors.log
  $ cat hg.pid >> $DAEMON_PIDS
  $ hg clone http://localhost:$HGPORT/ test4 # bundle2+
  abort: authorization failed
  [255]
  $ hg clone http://localhost:$HGPORT/ test4 --config devel.legacy.exchange=bundle1
  abort: authorization failed
  [255]
  $ killdaemons.py

serve errors

  $ cat errors.log
  $ req() {
  >     hg serve -p $HGPORT -d --pid-file=hg.pid -E errors.log
  >     cat hg.pid >> $DAEMON_PIDS
  >     hg --cwd ../test pull http://localhost:$HGPORT/
  >     killdaemons.py hg.pid
  >     echo % serve errors
  >     cat errors.log
  > }

expect error, pulling not allowed

  $ req
  pulling from http://localhost:$HGPORT/
  abort: authorization failed
  % serve errors

  $ cd ..