{"action":"opened","issue":{"url":"https://api.github.com/repos/vmlaker/mpipe/issues/10","labels_url":"https://api.github.com/repos/vmlaker/mpipe/issues/10/labels{/name}","comments_url":"https://api.github.com/repos/vmlaker/mpipe/issues/10/comments","events_url":"https://api.github.com/repos/vmlaker/mpipe/issues/10/events","html_url":"https://github.com/vmlaker/mpipe/issues/10","id":67456342,"number":10,"title":"Disable fan-in linkage.","user":{"login":"vmlaker","id":4021901,"avatar_url":"https://avatars.githubusercontent.com/u/4021901?v=3","gravatar_id":"","url":"https://api.github.com/users/vmlaker","html_url":"https://github.com/vmlaker","followers_url":"https://api.github.com/users/vmlaker/followers","following_url":"https://api.github.com/users/vmlaker/following{/other_user}","gists_url":"https://api.github.com/users/vmlaker/gists{/gist_id}","starred_url":"https://api.github.com/users/vmlaker/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vmlaker/subscriptions","organizations_url":"https://api.github.com/users/vmlaker/orgs","repos_url":"https://api.github.com/users/vmlaker/repos","events_url":"https://api.github.com/users/vmlaker/events{/privacy}","received_events_url":"https://api.github.com/users/vmlaker/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-04-09T21:36:28Z","updated_at":"2015-04-09T21:36:28Z","closed_at":null,"body":"Fan-in linkage should not be allowed. For example:\r\n```python\r\nstage1.link(stage2.link(stage3))\r\nstage1.link(stage3)  # This is bad.\r\n```\r\nIn the second line above, `link()` method should detect that stage3 has already been linked as an output stage, and an exception should be thrown. "}}