Fishing rod in offhand, bobber immediately disappears/goes to 0,0

Can confirm for 32a

Can confirm, very irritating when I want to get enough fish to dual wield and tame kitties.

Confirmed for 15w35b. It's not good to fish at night without a sword readied and able to fend off enemies wandering in from the riverbank.

Confirmed for 15w37a

Confirmed for

• 15w38b The line and the bobber are visible for less than a second, however the line also starts from the mainhand

Confirmed for 15w39b

Confirmed of 15w39c

Confirmed of 15w40a

Confirmed for 15w41b

Confirmed for 15w42a

Affects 15w43a

Confirmed for 15w44b

Confirmed for 15w47c

Confirmed for 15w50a

Confirmed for 16w03a

Confirmed for 16w04a

Another Confirmed for 16w04a

Confirmed for 16w05a

Confirmed for 16w05b

Confirmed for 16w06a

Confirmed for 16w07a

Confirmed for 16w07b

Confirmed for 1.9 Pre-Release 1

Confirmed for 1.9 Pre-Release 2

Confirmed for 1.9 Pre-Release 3

Confirmed for 1.9 Pre-Release 4

Confirmed for Minecraft Release 1.9

Please link to this comment in the description

The following is based on decompiled version of Minecraft 1.9 using MCP 9.24 beta. All method and class names are the names used in the decompiled version.

The reason why this happens is because the net.minecraft.entity.projectile.EntityFishHook.onUpdate() method only tests if the player is holding a fishing rod in his main hand.

public void onUpdate()
{
    super.onUpdate();

    if (this.worldObj.isRemote)
    {
        int i = ((Integer)this.getDataManager().get(field_184528_c)).intValue();

        if (i > 0 && this.caughtEntity == null)
        {
            this.caughtEntity = this.worldObj.getEntityByID(i - 1);
        }
    }
    else
    {
        // Replaced this
        //ItemStack itemstack = this.angler.getHeldItemMainhand();
        //
        //if (this.angler.isDead || !this.angler.isEntityAlive() || itemstack == null || itemstack.getItem() != Items.fishing_rod || this.getDistanceSqToEntity(this.angler) > 1024.0D)
        ItemStack itemStackMainhand = this.angler.getHeldItemMainhand();
        ItemStack itemStackOffhand = this.angler.getHeldItemOffhand();
        
        if (this.angler.isDead || !this.angler.isEntityAlive() || !(
                    (itemStackMainhand != null && itemStackMainhand.getItem() == Items.fishing_rod) ||
                    (itemStackOffhand != null && itemStackOffhand.getItem() == Items.fishing_rod))
                || this.getDistanceSqToEntity(this.angler) > 1024.0D)
        {
            this.setDead();
            this.angler.fishEntity = null;
            return;
        }
    }
    
    //...
}

There are however multiple other fixes required as well.
The net.minecraft.item.ItemFishingRod.ItemFishingRod().new IItemPropertyGetter() {...}.apply(ItemStack, World, EntityLivingBase) method needs to be changed to show a casted fishing rod for the offhand. The problem is that currently no hand parameter is provided so the complete method needs to be changed.

The net.minecraft.client.renderer.entity.RenderFish.doRender(EntityFishHook, double, double, double, float, float) method needs to be changed as well to draw the line from the correct hand.

Confirmed for 1.9.1 Pre-Release 1

Confirmed for 1.9.1-pre2

Confirmed for 1.9.1 Pre-Release 3

Confirmed for 1.9.1 Full Release

Confirmed for 1.9.2

Confirmed for 16w14a

Confirmed for 16w15a

Confirmed for 16w15b

Confirmed for 1.9.3 Pre-Release 1

Confirmed for 1.9.3 Pre-Release 2

Confirmed for 1.9.3 Pre-Release 3

Confirmed for 1.9.4

Confirmed for 16w21a and 16w21b

Confirmed for 1.10-pre1

This has been a huge issue for the longest time, Can someone please find a mod to assign this to?