in src/main/scala/com/googlesource/gerrit/plugins/analytics/common/CommitsStatistics.scala [58:66]
def + (that: CommitsStatistics) = {
require(this.isForMergeCommits == that.isForMergeCommits, "Cannot sum a merge commit stats with a non merge commit stats")
this.copy(
addedLines = this.addedLines + that.addedLines,
deletedLines = this.deletedLines + that.deletedLines,
commits = this.commits ++ that.commits,
issues = this.issues ++ that.issues
)
}