view tests/test-template-engine.t @ 29859:a1092e2d70a3

help: internals topic for wire protocol

The Mercurial wire protocol is under-documented. This includes a lack
of source docstrings and comments as well as pages on the official
wiki.

This patch adds the beginnings of "internals" documentation on the
wire protocol.

The documentation should have nearly complete coverage on the
lower-level parts of the protocol, such as the different transport
mechanims, how commands and arguments are sent, capabilities, and,
of course, the commands themselves.

As part of writing this documentation, I discovered a number of
deficiencies in the protocol and bugs in the implementation. I've
started sending patches for some of the issues. I hope to send a lot
more.

This patch starts with the scaffolding for a new internals page.

  $ cat > engine.py << EOF
  > 
  > from mercurial import templater
  > 
  > class mytemplater(object):
  >     def __init__(self, loader, filters, defaults, aliases):
  >         self.loader = loader
  > 
  >     def process(self, t, map):
  >         tmpl = self.loader(t)
  >         for k, v in map.iteritems():
  >             if k in ('templ', 'ctx', 'repo', 'revcache', 'cache'):
  >                 continue
  >             if hasattr(v, '__call__'):
  >                 v = v(**map)
  >             v = templater.stringify(v)
  >             tmpl = tmpl.replace('{{%s}}' % k, v)
  >         yield tmpl
  > 
  > templater.engines['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 ..