Applying effect with amplifier higher than 127 before current potion effect ends causes timer to stay at 0:00

Is this still an issue in 15w45a? If so, please explain the issue in detail and provide steps to reproduce it. Please also update the list of affected versions.

Confirmed for

• 15w47c

Just have a repeating command block running a /testfor command and then a conditional chain command block that gives you the effect.

testfor command

/testfor @p {ActiveEffects:[{Duration:1}]}

It looks like this is caused only by the high amplifier but not by the duration

Please change the summary (title) of the report to something like "Potion effects with high amplifiers remain displayed in inventory after timer reaches 0:00"

So regular amplifiers are not an issue?

redstonehelper, yes it is.

Please link to this comment in the description

The following is based on a decompiled version of Minecraft 1.9 using MCP 9.24 beta.

This is a valid report because the method net.minecraft.client.network.NetHandlerPlayClient.handleEntityEffect(SPacketEntityEffect) is not reading the amplifier correctly. The packet stores the amplifier as unsigned byte (0 to 255), however the client reads it as signed byte (-128 to 127). Because of this the client thinks the amplifier is lower and does not extend the duration of the effect. The effect remains however as the client does not receive a SPacketRemoveEntityEffect packet, because for the server, the potion duration was extended.

public void handleEntityEffect(SPacketEntityEffect packetIn)
{
    PacketThreadUtil.checkThreadAndEnqueue(packetIn, this, this.gameController);
    Entity entity = this.clientWorldController.getEntityByID(packetIn.getEntityId());

    if (entity instanceof EntityLivingBase)
    {
        Potion potion = Potion.getPotionById(packetIn.getEffectId());

        if (potion != null)
        {
            // Replaced this
            //PotionEffect potioneffect = new PotionEffect(potion, packetIn.getDuration(), packetIn.getAmplifier(), packetIn.func_186984_g(), packetIn.func_179707_f());
            PotionEffect potioneffect = new PotionEffect(potion, packetIn.getDuration(), Byte.toUnsignedInt(packetIn.getAmplifier()), packetIn.func_186984_g(), packetIn.func_179707_f());
            
            potioneffect.setPotionDurationMax(packetIn.func_149429_c());
            ((EntityLivingBase)entity).addPotionEffect(potioneffect);
        }
    }
}

Is this still an issue in the latest snapshot 16w44a? If so please update the affected versions.

This is an automated comment on any open or reopened issue with out-of-date affected versions.

Confirmed for 1.13.1-pre1

Fixed in 1.15.2. The effect doesn't remain at 0:00 when the 10 seconds potion ends.

Probably fixed due to the fix for MC-1541.