fix: don't include empty pre_load, load and post_load tags by default

beet/contrib/lantern_load.py

@@ -27,7 +27,7 @@ def beet_default(ctx: Context):
         f"{id}:load",
     ]
 
-    ctx.data.function_tags["load:load"].data["values"].append(f"#{id}:load")
+    ctx.data.function_tags.setdefault("load:load", FunctionTag()).add(f"#{id}:load")
     ctx.data[f"{id}:load"] = FunctionTag({"values": load_tag_values})
 
     # Generate and join version checks for all the dependencies.
@@ -73,11 +73,3 @@ def base_data_pack(ctx: Context):
             "scoreboard players reset * load.status",
         ]
     )
-
-    ctx.data.function_tags.merge(
-        {
-            "load:pre_load": FunctionTag(),
-            "load:load": FunctionTag(),
-            "load:post_load": FunctionTag(),
-        }
-    )

beet/library/data_pack.py

@@ -186,6 +186,20 @@ def prepend(self: TagFileType, other: TagFileType) -> bool:  # type: ignore
             if value not in values:
                 values.insert(0, deepcopy(value))
 
+    def add(self, value: str):
+        """Add an entry."""
+        values = self.data.setdefault("values", [])
+        if value not in values:
+            values.append(value)
+
+    def remove(self, value: str):
+        """Remove an entry."""
+        values = self.data.setdefault("values", [])
+        try:
+            values.remove(value)
+        except ValueError:
+            pass
+
     @classmethod
     def default(cls) -> JsonDict:
         return {"values": []}