Add setting to preserve fly on gamemode change

Essentials/src/main/java/com/earth2me/essentials/EssentialsPlayerListener.java

@@ -52,6 +52,7 @@
 import org.bukkit.event.player.PlayerCommandPreprocessEvent;
 import org.bukkit.event.player.PlayerEggThrowEvent;
 import org.bukkit.event.player.PlayerFishEvent;
+import org.bukkit.event.player.PlayerGameModeChangeEvent;
 import org.bukkit.event.player.PlayerInteractEvent;
 import org.bukkit.event.player.PlayerJoinEvent;
 import org.bukkit.event.player.PlayerLoginEvent;
@@ -1059,6 +1060,27 @@ public void onPlayerFishEvent(final PlayerFishEvent event) {
         user.updateActivityOnInteract(true);
     }
 
+    @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
+    public void onPlayerGameModeChange(final PlayerGameModeChangeEvent event) {
+        if (!ess.getSettings().isGamemodeChangePreserveFlying()) {
+            return;
+        }
+
+        final User user = ess.getUser(event.getPlayer());
+        if (!user.isAuthorized("essentials.fly")) {
+            return;
+        }
+
+        final Player player = event.getPlayer();
+        if (player.isFlying() && player.getAllowFlight() && user.isAuthorized("essentials.fly")) {
+            // The gamemode change happens after the event, so we need to delay the flight enable
+            ess.scheduleSyncDelayedTask(() -> {
+                player.setAllowFlight(true);
+                player.setFlying(true);
+            }, 1);
+        }
+    }
+
     private static final class ArrowPickupListener implements Listener {
         @EventHandler(priority = EventPriority.LOW)
         public void onArrowPickup(final org.bukkit.event.player.PlayerPickupArrowEvent event) {

Essentials/src/main/java/com/earth2me/essentials/ISettings.java

@@ -356,6 +356,8 @@ public interface ISettings extends IConf {
 
     boolean isWorldChangePreserveFlying();
 
+    boolean isGamemodeChangePreserveFlying();
+
     boolean isWorldChangeSpeedResetEnabled();
 
     long getCommandCooldownMs(String label);

Essentials/src/main/java/com/earth2me/essentials/Settings.java

@@ -1964,6 +1964,11 @@ public boolean isWorldChangePreserveFlying() {
         return config.getBoolean("world-change-preserve-flying", true);
     }
 
+    @Override
+    public boolean isGamemodeChangePreserveFlying() {
+        return config.getBoolean("gamemode-change-preserve-flying", false);
+    }
+
     @Override
     public boolean isWorldChangeSpeedResetEnabled() {
         return config.getBoolean("world-change-speed-reset", true);

Essentials/src/main/resources/config.yml

@@ -235,6 +235,11 @@ world-change-fly-reset: true
 # This will only work if the player has the 'essentials.fly' permission.
 world-change-preserve-flying: true
 
+# Should Essentials preserve a player's flight status when they change game modes?
+# When enabled, if a player is flying when switching game modes, their flight will be maintained.
+# This will only work if the player has the 'essentials.fly' permission.
+gamemode-change-preserve-flying: false
+
 # When a player changes worlds, should Essentials reset their speed according to their permissions?
 # This resets the player's speed to the default if they don't have 'essentials.speed'.
 # If the player doesn't have 'essentials.speed.bypass', their speed will be reset to the maximum values