in teamcity-premerge-agent/src/main/java/jetbrains/buildServer/premerge/PremergeBranchSupportImpl.java [161:170]
public void mergeAbort() throws VcsException {
try {
myFacade.merge()
.setAbort(true)
.call();
} catch (Exception e) {
myProcess.getBuild().getBuildLogger().error("Merge abort error");
throw new VcsException(e);
}
}