Cancelling a constructor [CandleCakeBlock]

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I have a mixin:

@Mixin(CandleCakeBlock.class)
public class CandleCakeBlockMixin {
    @Shadow
    @Final
    private static Map<Block, CandleCakeBlock> CANDLES_TO_CANDLE_CAKES;

    @Inject(at = @At(value = "INVOKE", target = "Ljava/util/Map;put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;", ordinal = 0), method = "<init>", cancellable = true)
    private void avoidMapInsertion(Block candle, AbstractBlock.Settings settings, CallbackInfo ci) {
        if (CANDLES_TO_CANDLE_CAKES.containsKey(candle)) {
            ci.cancel();
        }
    }
}

that is meant to cancel my cakes getting added to this "CANDLES_TO_CANDLE_CAKES" map (as I do candle cake handling differently). However, I get this error:

@At("INVOKE") selector (cancellable = true) Found @Inject targetting a constructor in injector net/minecraft/block/CandleCakeBlock::avoidMapInsertion [PREINJECT Applicator Phase -> bagels_baking.mixins.json:block.CandleCakeBlockMixin -> Prepare Injections ->  -> handler$zgi000$avoidMapInsertion(Lnet/minecraft/block/Block;Lnet/minecraft/block/AbstractBlock$Settings;Lorg/spongepowered/asm/mixin/injection/callback/CallbackInfo;)V -> Prepare]```

that leads me to believe constructors can't be cancelled. Am I wrong in this and my mixin is bad, or should I be doing something different here?

[Chocohead]

It is intensional that constructors can't be cancelled, your mixin will need a little rethinking (perhaps adding after vanilla instead of before and preventing replacement)

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The solution in this particular instance was to use a redirect at the invocation of the .put call. From there we can cancel the call on the condition that it's one of the cake blocks that I'm adding in. Which is exactly what I wanted.

@Redirect(method = "<init>", at = @At(value = "INVOKE", target = "Ljava/util/Map;put(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;"))
private <K, V> V put(Map<K, V> map, K key, V value) {
    return value instanceof BasicCandleCakeBlock ? null : map.put(key, value);
}

Credit to deirn on discord for this solution