Hooks: Allow updating hook handler without affecting order.

It will throw an error if you're trying to update a hook using a different hook_type api to prevent any weirdness by jumping from one chain to the other.

Also created a specialized function for hook_data initialization.

vmf/scripts/mods/vmf/modules/core/hooks.lua

@@ -130,8 +130,19 @@ local function get_hook_chain(orig)
     end
 end
 
+-- Returns a table containing hook data inside of it.
+-- { active = self:is_enabled() }
+local function create_hook_data(self, obj, handler, hook_type)
+    return {
+        active = self:is_enabled(),
+        hook_type = hook_type,
+        handler = handler,
+        obj = obj,
+    }
+end
+
 -- Returns a function closure with all the information needed for a given hook to be handled correctly.
-local function create_specialized_hook(self, orig, handler, hook_type)
+local function create_specialized_hook(self, orig, hook_type)
     local func
     local hook_data = _registry[self][orig]
 
@@ -144,7 +155,7 @@ local function create_specialized_hook(self, orig, handler, hook_type)
     if hook_type == HOOK_TYPE_NORMAL then
         func = function(...)
             if hook_data.active then
-                return handler(previous_hook, ...)
+                return hook_data.handler(previous_hook, ...)
             else
                 return previous_hook(...)
             end
@@ -153,7 +164,7 @@ local function create_specialized_hook(self, orig, handler, hook_type)
     elseif hook_type == HOOK_TYPE_ORIGIN then
         func = function(...)
             if hook_data.active then
-                return handler(...)
+                return hook_data.handler(...)
             else
                 return orig(...)
             end
@@ -161,7 +172,7 @@ local function create_specialized_hook(self, orig, handler, hook_type)
     elseif hook_type == HOOK_TYPE_SAFE then
         func = function(...)
             if hook_data.active then
-                vmf.xpcall_no_return_values(self, "(safe_hook)", handler, ...)
+                vmf.xpcall_no_return_values(self, "(safe_hook)", hook_data.handler, ...)
             end
         end
     end
@@ -203,8 +214,9 @@ local function create_hook(self, orig, obj, method, handler, func_name, hook_typ
     end
 
     -- Check to make sure it wasn't hooked before
-    if not _registry[self][orig] then
-        _registry[self][orig] = { active = self:is_enabled() }
+    local hook_data = _registry[self][orig]
+    if not hook_data then
+        _registry[self][orig] = create_hook_data(self, obj, handler, hook_type)
 
         local hook_registry = _registry.hooks[hook_type]
         -- Add to the hook to registry. Origin hooks are unique, so we check for that too.
@@ -212,18 +224,26 @@ local function create_hook(self, orig, obj, method, handler, func_name, hook_typ
             if hook_registry[orig] then
                 self:error("(%s): Attempting to hook origin of already hooked function %s", func_name, method)
             else
-                hook_registry[orig] = create_specialized_hook(self, orig, handler, hook_type)
+                hook_registry[orig] = create_specialized_hook(self, orig, hook_type)
             end
         else
-            table.insert(hook_registry[orig], create_specialized_hook(self, orig, handler, hook_type) )
+            table.insert(hook_registry[orig], create_specialized_hook(self, orig, hook_type) )
         end
+    else
+        -- If hook_data already exists and it's the same hook_type, we can safely change the hook handler.
+        -- This should (in practice) only be used for debugging by modders who uses DoFile.
+        -- Revisit purpose when lua files are in plain text.
+        if hook_data.obj == obj and hook_data.hook_type == hook_type then
+            hook_data.handler = handler
         else
             -- This should be a warning log, but currently there are no differences between warning and error.
             -- Wouldn't want to scare users that mods are broken because this used to be acceptable.
+            -- This should be changed to permanently be a warning log after new_hooks deprecation period is over.
             if vmf:get("developer_mode") then
-            self:warning("(%s): Attempting to rehook already active hook %s.", func_name, method)
+                self:warning("(%s): Attempting to rehook active hook [%s] with different hook_type.", func_name, method)
             else
-            self:info("(%s): Attempting to rehook already active hook %s.", func_name, method)
+                self:info("(%s): Attempting to rehook active hook [%s] with different hook_type.", func_name, method)
+            end
         end
     end