I have given my 2 villagers tons of carrots and there are plenty of doors around and they will not breed. I have tested this in both my survival world and creative world and neither has allowed my villagers to breed.
The screenshot was of my creative world testing the bug. Obviously much more doors and carrots were used but to no effect.
Side note, I don't know if this is related but in the villages.dat file, there are 0 entries for villages and i know I've found many villages in the world and have made my own village for breeding purposes