Enable automatic proxy detection for remote push()

See #642

Author: sathieu

pygit2/remote.py

@@ -237,7 +237,7 @@ def push_refspecs(self):
 
         return strarray_to_strings(specs)
 
-    def push(self, specs, callbacks=None):
+    def push(self, specs, callbacks=None, proxy=None):
         """
         Push the given refspec to the remote. Raises ``GitError`` on protocol
         error or unpack failure.
@@ -252,9 +252,21 @@ def push(self, specs, callbacks=None):
 
         specs : [str]
             Push refspecs to use.
+
+        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/`)
         """
         with git_push_options(callbacks) as payload:
             opts = payload.push_options
+            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(specs) as refspecs:
                 err = C.git_remote_push(self._remote, refspecs, opts)
                 payload.check_error(err)