Pushing and new heads in mercurial

I'd like to see what exactly would be created during a push, if I get the abort: push c开发者_StackOverflow中文版reates new remote heads! error. How can I check that?

Some more details: I'm pulling from one repository (upstream) and pushing to a local fork which does have additional branches, but already contains all upstream ones. Also, I'm only pushing one upstream branch.

When I look at hg outgoing <fork_repo>, I see a stream of commits with a parent and then some commits without. I'm not sure how to understand that really.

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The simplest way is to run hg pull. That way, your local repository will contain exactly what the remote repository will contain after the push.

If you don't want to pull, combining hg incoming and hg outgoing will usually give you enough information to see which are the two heads.