phabricator: add support for using the vcr library to mock interactions

I'll use this in an upcoming test. The decorator dancing in this is
more complicated than I'd like, but it beats repeating all this code
everywhere.

Differential Revision: https://phab.mercurial-scm.org/D4600

contrib/phabricator.py

@@ -106,6 +106,37 b' colortable = {'
     b'phabricator.node': b'',
 }
 
+_VCR_FLAGS = [
+    (b'', b'test-vcr', b'',
+     _(b'Path to a vcr file. If nonexistent, will record a new vcr transcript'
+       b', otherwise will mock all http requests using the specified vcr file.'
+       b' (ADVANCED)'
+     )),
+]
+
+def vcrcommand(name, flags, spec):
+    fullflags = flags + _VCR_FLAGS
+    def decorate(fn):
+        def inner(*args, **kwargs):
+            cassette = kwargs.pop(r'test_vcr', None)
+            if cassette:
+                import hgdemandimport
+                with hgdemandimport.deactivated():
+                    import vcr as vcrmod
+                    import vcr.stubs as stubs
+                vcr = vcrmod.VCR(
+                    serializer=r'json',
+                    custom_patches=[
+                        (urlmod, 'httpconnection', stubs.VCRHTTPConnection),
+                        (urlmod, 'httpsconnection', stubs.VCRHTTPSConnection),
+                    ])
+                with vcr.use_cassette(cassette):
+                    return fn(*args, **kwargs)
+            return fn(*args, **kwargs)
+        inner.__name__ = fn.__name__
+        return command(name, fullflags, spec)(inner)
+    return decorate
+
 def urlencodenested(params):
     """like urlencode, but works with nested parameters.
 
@@ -215,7 +246,7 b' def callconduit(repo, name, params):'
         raise error.Abort(msg)
     return parsed[r'result']
 
-@command(b'debugcallconduit', [], _(b'METHOD'))
+@vcrcommand(b'debugcallconduit', [], _(b'METHOD'))
 def debugcallconduit(ui, repo, name):
     """call Conduit API
 
@@ -452,7 +483,7 b' def userphids(repo, names):'
                           % b' '.join(sorted(unresolved)))
     return [entry[r'phid'] for entry in data]
 
-@command(b'phabsend',
+@vcrcommand(b'phabsend',
          [(b'r', b'rev', [], _(b'revisions to send'), _(b'REV')),
           (b'', b'amend', True, _(b'update commit messages')),
           (b'', b'reviewer', [], _(b'specify reviewers')),
@@ -909,7 +940,7 b' def readpatch(repo, drevs, write):'
         content = b'%s%s\n%s' % (header, desc, body)
         write(encoding.unitolocal(content))
 
-@command(b'phabread',
+@vcrcommand(b'phabread',
          [(b'', b'stack', False, _(b'read dependencies'))],
          _(b'DREVSPEC [OPTIONS]'))
 def phabread(ui, repo, spec, **opts):
@@ -936,7 +967,7 b' def phabread(ui, repo, spec, **opts):'
     drevs = querydrev(repo, spec)
     readpatch(repo, drevs, ui.write)
 
-@command(b'phabupdate',
+@vcrcommand(b'phabupdate',
          [(b'', b'accept', False, _(b'accept revisions')),
           (b'', b'reject', False, _(b'reject revisions')),
           (b'', b'abandon', False, _(b'abandon revisions')),