Can't do pull request to GitHub

Please see this comment: http://youtrack.jetbrains.com/issue/IDEA-115375#comment=27-610859 .
If it don't be useful, please attach idea.log (Help | Show log).

I attached log

This error means that target branch (the one we want to appy changes TO) is invalid for some reason. (ex: it doesn't exist)

But this shouldn't happen for default settings.

If you have spare time, could you check this in PhpStorm 8 EAP ?

I tested it with PhpStorm 8, it works.

I ran into the same issue. I am using 

IntelliJ IDEA 2017.1.3
Build #IU-171.4424.56, built on May 12, 2017
Licensed to LinkedIn Corporation

JRE: 1.8.0_112-release-736-b21 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.12.5

IntelliJ IDEA 2017.1.3
Build #IU-171.4424.56, built on May 12, 2017
Licensed to LinkedIn Corporation

JRE: 1.8.0_112-release-736-b21 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.12.5

It used to work for me and it stopped working one day. I am not sure what changed.

The diff looks fine. So I don't think the solution suggested by the referenced link would apply to my case.

Do you get exactly the same error, including the [PullRequest;base]invalid: null part? Or maybe this one is different?

This is the error I got:

Can't Create Pull Request

Can't create pull request

422 Unprocessable Entity - Validation Failed

[PullRequest; head]invalid: null

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I got this error when I had my origin remote set up so that it will fetch from the upstream and push to my own fork.

After I changed it back to fetch from my own fork, the problem went away.