Small doubt on update a partition when some rows need to move among partition

I am trying to handle the limit that we can't do a tuple move caused by BEFORE TRIGGER,

during which I get two doubt points:

The first issue:

In ExecBRUpdateTriggers() or ExecBRInsertTriggers() function why we need to check the

result slot after every trigger call. If we should check the result slot after all triggers are

called.

For example, we have a table t1(i int, j int), and a BEFORE INSERT TRIGGER on t1 make i - 1, 

and another BEFORE INSERT TRIGGER on t1 make i + 1. If the first trigger causes a partition

move, then the insert query will be interrupted. However, it will not change partition after

all triggers are called.

The second issue:

I read the code for partition move caused by an update, it deletes tuple in an old partition

and inserts a new tuple in a partition. But during the insert, it triggers the trigger on the new

I make an initial patch as my thought, sorry if I missing some of the historical discussion.