-In these tables, A, B, C and D are some different states of a
-file. For example, the last line of the last table means that if a
-file is in state B in the working tree and the index, and in a
-different state C in HEAD and in the target, then "git reset
---merge target" will put the file in state C in the working tree,
-in the index and in HEAD.
+ working index HEAD target working index HEAD
+ ----------------------------------------------------
+ B C C D --soft B C D
+ --mixed B D D
+ --hard D D D
+ --merge (disallowed)
+
+ working index HEAD target working index HEAD
+ ----------------------------------------------------
+ B C C C --soft B C C
+ --mixed B C C
+ --hard C C C
+ --merge B C C
+
+"reset --merge" is meant to be used when resetting out of a conflicted
+merge. Any mergy operation guarantees that the work tree file that is
+involved in the merge does not have local change wrt the index before
+it starts, and that it writes the result out to the work tree. So if
+we see some difference between the index and the target and also
+between the index and the work tree, then it means that we are not
+resetting out from a state that a mergy operation left after failing
+with a conflict. That is why we disallow --merge option in this case.