tests/failfilemerge.py

hgweb: always return iterable from @webcommand functions (API)

We had to hack up this function to support our transition to the
new response API. Now that we're done with the transition (!!),
we can return to returning an iterator of content chunks from
these functions.

It is tempting to return a normal object and not a generator.
However, as the keyword extension demonstrates, extensions may
wish to wrap commands and have a try..finally block around
execution. Since there is a generator producing content and
that generator could be executing code, the try..finally needs
to live for as long as the generator is running. That means we
have to return a generator so wrappers can consume the generator
inside a try..finally.

.. api::

   hgweb @webcommand functions must use the new response object
   passed in via ``web.res`` to initiate sending of a response.
   The hgweb WSGI application will no longer start sending the
   response automatically.

Differential Revision: https://phab.mercurial-scm.org/D2796

# extension to emulate interrupting filemerge._filemerge

from __future__ import absolute_import

from mercurial import (
    error,
    extensions,
    filemerge,
)

def failfilemerge(filemergefn,
                  premerge, repo, wctx, mynode, orig, fcd, fco, fca,
                  labels=None):
    raise error.Abort("^C")
    return filemergefn(premerge, repo, mynode, orig, fcd, fco, fca, labels)

def extsetup(ui):
    extensions.wrapfunction(filemerge, '_filemerge',
                            failfilemerge)