Unexpected Jenkins Build

[tsako.t...@gmail.com]

Hi All,

I'm use Jenkins Pipeline in SCM polling trigger to GitHub

But occur there is In the middle of the night Unexpected build...

I would like to somehow identify the cause and take measures.

Is there a pull request?

Not, the corresponding branch project has not been touched or committed at all these days.

The corresponding activity that can be checked from Blue Ocean is also No changes.

About Checking Scan Repository Log?

Unconfirmed

It is overwritten every SCM polling, 

so when indexing / indexing.log moves in the middle of the night, it gets out of hand

If I can see Scan Repository Log, confirm 

0 pull requests were processed.

it think facilitate problem isolation

I am investigating whether there is a way to control the output method of the log here.

any suggestions on how to fix this?

Behaviours setting of the trigger part?

As follows

Discover pull requests from forks：
Merging the pull request with the current target branch revision


Discover pull requests from origin：
Merging the pull request with the current target branch revision

Other things I tried

When I searched around the ticket of GithubBranchSoucePlugin, 

the cache size of GitHubSCM is 0 in the startup argument of jvm because it was mentioned about the cache size

https://wiki.jenkins.io/display/JENKINS/GitHub+Branch+Source+Plugin

-Dorg.jenkinsci.plugins.github_branch_source.GitHubSCMSource.cacheSize=0

No effect, not a problem like caching?

After all it seems that judgment of the trigger execution part is bad ...?

Supplementary information

The plugins for Jenkins and SCM polls are as follows

Jenkins ver. 2.150.3

GitHub-Branch-Source 2.4.2

Any suggestions, ideas and tips is highly appreciated.