1-tick weapon swap keeps old base damage & charge progress, uses new enchants & unique traits

Summary

Within exactly 1 game tick after switching held weapons, melee attacks combine conflicting weapon properties incorrectly:

1. Inherits base attack damage and full attack charge progress from the weapon you swapped away from

2. Applies all enchantments, special weapon mechanics (axe shield-break, mace breach, sword sweep, etc.) of the newly selected weapon

   This creates an unfair PvP exploit by mixing high raw damage with powerful enchant/trait effects in one hit.

Steps to Reproduce

1. Create a new vanilla survival world, no mods, no resource packs.

2. Obtain two distinct melee weapons for testing:

   Example A: Netherite Axe (high base damage, shield-breaking trait) in hotbar slot 1

   Example B: Wooden Sword enchanted Fire Aspect III in hotbar slot 2

3. Target a mob/player for testing (summon husk ~ ~ ~ {NoAI:1} for stable health reading)

4. Hold slot 1 axe, hold right mouse to fully fill attack charge meter.

5. On the exact same tick you release right-click to swing, instantly hotkey switch to slot 2 sword within 1 tick window.

6. Observe the hit result.

   Repeat reverse test: charge sword first, swap to mace in 1 tick to verify mace breach works with sword base damage.

Actual Result

The attack deals the original axe’s high base damage, carries over the full charge multiplier, and triggers the new sword’s Fire Aspect burn effect simultaneously. All special traits of the second weapon activate (shield break, armor piercing breach, sweep attack, etc.).

Expected Result

All damage calculation, charge progress, enchantments and weapon special traits must read only the currently held weapon at the moment the swing lands. No cross-weapon stat mixing should occur in any tick window.

Additional Notes

This exploit is widely known in PvP communities as attribute swap / breach swap. It severely unbalances combat by letting players stack the highest raw damage weapon with the most impactful enchant/trait weapon in a single hit. The bug window is limited strictly to 1 tick after item switch. Video/screenshot recording of reproduction can be attached as proof.