how to create a preop trigger to prevent a new baseline in clearcase stream?

Question

I have this issue while rebasing the stream: cleartool: Error: Can't switch to baseline because the stream has made changes based on the current baseline.

giraffe_pvob is a non modifiable component on tiger_011 project and there were no changes done on this component by the stream.

I would like to install the preop trigger to prevent any new baseline on this stream. so how should I proceed? Will this prevent any rebasing issue like above?

Thanks !!

Answer 1

You cannot prevent the creation of the baseline, but you can prevent the situation which leads to said baseline on a non-modifiable component.

This is called a parasite baseline, and is one of UCM flaws.

It is caused by a dependency, as explained in "ClearCase UCM - best practices using components".

A1
  B1
B2

Putting a baseline on A will create a parasite baseline on B, even if B is a non-modifiable component...
(more details in this thread)

The only preop I usually put is one (on rebase) making sure none of the foundation components (like B) of a stream are part of the dependencies of another (modifiable) component (like A depending on B)