tests/test-template-engine.t

debugcommands: support sending HTTP requests with debugwireproto

We implement an action that can issue an HTTP request. We can define
headers via arguments and specify a file to use for the HTTP request
body.

The request uses the HTTP peer's opener, which is already configured
for auth, etc. This is both good and bad. Good in that we get some
nice behavior out of the box. Bad in that some HTTP request headers
are added automatically.

Differential Revision: https://phab.mercurial-scm.org/D2841

  $ cat > engine.py << EOF
  > 
  > from mercurial import (
  >     pycompat,
  >     templater,
  >     templateutil,
  > )
  > 
  > class mytemplater(templater.engine):
  >     def _load(self, t):
  >         return self._loader(t)
  > 
  >     def process(self, t, map):
  >         tmpl = self._load(t)
  >         props = self._defaults.copy()
  >         props.update(map)
  >         for k, v in props.items():
  >             if b'{{%s}}' % k not in tmpl:
  >                 continue
  >             if callable(v) and getattr(v, '_requires', None) is None:
  >                 props = self._resources.copy()
  >                 props.update(map)
  >                 v = v(**pycompat.strkwargs(props))
  >             elif callable(v):
  >                 v = v(self, props)
  >             v = templateutil.stringify(v)
  >             tmpl = tmpl.replace(b'{{%s}}' % k, v)
  >         yield tmpl
  > 
  > templater.engines[b'my'] = mytemplater
  > EOF
  $ hg init test
  $ echo '[extensions]' > test/.hg/hgrc
  $ echo "engine = `pwd`/engine.py" >> test/.hg/hgrc
  $ cd test
  $ cat > mymap << EOF
  > changeset = my:changeset.txt
  > EOF
  $ cat > changeset.txt << EOF
  > {{rev}} {{node}} {{author}}
  > EOF
  $ hg ci -Ama
  adding changeset.txt
  adding mymap
  $ hg log --style=./mymap
  0 97e5f848f0936960273bbf75be6388cd0350a32b test

  $ cat > changeset.txt << EOF
  > {{p1rev}} {{p1node}} {{p2rev}} {{p2node}}
  > EOF
  $ hg ci -Ama
  $ hg log --style=./mymap
  0 97e5f848f0936960273bbf75be6388cd0350a32b -1 0000000000000000000000000000000000000000
  -1 0000000000000000000000000000000000000000 -1 0000000000000000000000000000000000000000

invalid engine type:

  $ echo 'changeset = unknown:changeset.txt' > unknownenginemap
  $ hg log --style=./unknownenginemap
  abort: invalid template engine: unknown
  [255]

  $ cd ..