Features used to implement the example

• Write field on linked issues or sub-tasks
• Virtual field "New watchers"

Example: Automatically become watcher of every issue blocking an issue assigned to you

We may be interested in automatically making an assignee watcher of every issue blocking the current issue, in order to react as soon as possible to any change in those issues. Post-function Write field on linked issues or sub-tasks is used to write the name or current issue's assignee into the virtual field "New watchers" of those issues linked with current issue using a "is blocked by" issue link. We will also become watcher of every issue transitively blocking our issue, i.e., any issue blocking another issue which is itself blocking current issue.  

ISSUE A --blocks--> ISSUE B --blocks--> ISSUE C --blocks--> ISSUE D, in this example issue A is blocking directly issue B and transitively issue C and D.  To implement this behavior we simply have to check option "Write linked issues and sub-tasks recursively" in post-function Write field on linked issues or sub-tasks.

We use post-function Write field on linked issues or sub-tasks to write field "Assignee" into virtual field "New watchers" in all blocking issues:

Once configured, the transition will look like this: