git – See merge conflicts before a rebase

In a Git repo, I create a branch (B) based on commit (number 203) of an other branch (A). Then I do some dev on my branch, and other commits are also pushed on A. Then, when I completed my dev I want to rebase/merge my branch on the main one.

Here a “graphical example”:

A202 - A203 - A204 - ... - A219
          B1 - B2 - B3

Would become:

A202 - A203 - A204 - ... - A219 - A220 (B1) - A221 (B2) - A222 (B3)

But before doing the rebase/merge, and thanks to Gerrit, I know there is some merge conflicts between my branch and the commits pushed on A. The problem is, before doing the rebase, I don’t know from which commits come the conflicts, and I don’t know what are the conflicts.

Is there a way (command, plug-in,…) to get the list of commits who cause the conflicts and to get the conflicts before doing anything ? (From Git or Gerrit)