Enable automatic proxy detection for remote fetch()

See #642

Author: sathieu

pygit2/remote.py

@@ -106,7 +106,7 @@ def save(self):
         err = C.git_remote_save(self._remote)
         check_error(err)
 
-    def fetch(self, refspecs=None, message=None, callbacks=None, prune=C.GIT_FETCH_PRUNE_UNSPECIFIED):
+    def fetch(self, refspecs=None, message=None, callbacks=None, prune=C.GIT_FETCH_PRUNE_UNSPECIFIED, proxy=None):
         """Perform a fetch against this remote. Returns a <TransferProgress>
         object.
 
@@ -118,11 +118,23 @@ def fetch(self, refspecs=None, message=None, callbacks=None, prune=C.GIT_FETCH_P
             repo, the second will remove any remote branch in the local
             repository that does not exist in the remote and the last will
             always keep the remote branches
+
+        proxy : None or True or str
+            Proxy configuration. Can be one of:
+
+            * `None` (the default) to disable proxy usage
+            * `True` to enable automatic proxy detection
+            * an url to a proxy (`http://proxy.example.org:3128/`)
         """
         message = to_bytes(message)
         with git_fetch_options(callbacks) as payload:
             opts = payload.fetch_options
             opts.prune = prune
+            if proxy is True:
+              opts.proxy_opts.type = C.GIT_PROXY_AUTO
+            elif proxy is not None:
+              opts.proxy_opts.type = C.GIT_PROXY_SPECIFIED
+              opts.proxy_opts.url = proxy
             with StrArray(refspecs) as arr:
                 err = C.git_remote_fetch(self._remote, arr, opts, to_bytes(message))
                 payload.check_error(err)