The as-yet-discussed issues for The White House and United States Department of State: 

Reasonable to conclude the Russian Federation will not invade the territory of Ukraine without the Russian Federation confirming in advance support from the People's Republic of China.  

If the Russian Federation invades Ukraine, the United States, European Union (EU) or members of the EU, along with other countries have pledged to respond robustly with commercial, economic, and political sanctions upon the Russian Federation. 

Subsequent to the implementation of sanctions against the Russian Federation, the People's Republic of China could implement commercial, economic, and political actions to mitigate impact upon the Russian Federation. 

Which leads to this question:  

What consequences will be imposed by the United States, EU or members of the EU, along with other countries upon the People’s Republic of China for its assistance to the Russian Federation?

How will then the People’s Republic of China react directly toward a country which has imposed consequences upon the People’s Republic of China?