For instance, A promises to obtain a mortgage. A gets the mortgage, and B promises to buy said house if B gets the mortgage. A then tells B that I refuse to apply for a mortgage, and the deal is off. A has repudiated her promise to do the thing that will bring into being the condition. B may also need to show that approval of the mortgage was likely that is that the breach of A s promise was the cause of the failure of the condition and hence the damage of the lack of sale, although it might also be sufficient for B just to show that A did not act in good faith, or use her best efforts, to procure the mortgage.
Anticipatory repudiation is repudiation but done before the performance is due.
It seems like if the renunciation of the duty is done at the time the performance is due or after it is due, it is no different than a breach. You are almost right. Most repudiations probably are before performance, and so anticipatory. In that case repudiation happens after performance or at least some performance. This is especially important with regard to whether the non-breaching party has to wait for cure or not.