fix reload_module ignoring pack environment

reload_module loaded the new module code with the global environment,
while require runs modules in their pack environment. After reload,
PACK_ID and other pack globals were nil in the module.

dev/tests/reload_module.lua

@@ -0,0 +1,33 @@
+-- reload_module must run the module in its pack environment, as require does
+local util = require "core:tests_util"
+util.create_demo_world()
+
+-- a pack with a module that uses pack environment (PACK_ID)
+local PACK = "world:content/reload_test"
+file.mkdirs(PACK .. "/modules")
+file.write(PACK .. "/package.json", json.tostring({id="reload_test", title="reload_test"}))
+
+local function write_module(version)
+    file.write(PACK .. "/modules/mod.lua", string.format([[
+local this = {}
+function this.info() return PACK_ID, %d end
+return this
+]], version))
+end
+
+write_module(1)
+app.reconfig_packs({"reload_test"}, {})
+app.tick()
+
+local mod = require "reload_test:mod"
+local packid, version = mod.info()
+assert(packid == "reload_test" and version == 1)
+
+write_module(2)
+reload_module("reload_test:mod")
+packid, version = mod.info()
+assert(version == 2, "module is not reloaded")
+assert(packid == "reload_test", "reloaded module has no pack environment")
+
+app.close_world(true)
+app.delete_world("demo")

res/scripts/stdmin.lua

@@ -183,6 +183,12 @@ function on_deprecated_call(name, alternatives)
     end
 end
 
+local __pack_envs = __vc__pack_envs
+function __vc_internals.get_pack_env(packid)
+    return __pack_envs[packid]
+end
+__vc__pack_envs = nil
+
 function reload_module(name)
     local prefix, name = parse_path(name)
     local path = prefix..":modules/"..name..".lua"
@@ -196,6 +202,10 @@ function reload_module(name)
     if script == nil then
         error(err)
     end
+    local env = __pack_envs[prefix]
+    if env then
+        script = setfenv(script, env)
+    end
     local result = script()
     if not result then
         return
@@ -270,12 +280,6 @@ function __vc_lock_internal_modules()
     __internal_locked = true
 end
 
-local __pack_envs = __vc__pack_envs
-function __vc_internals.get_pack_env(packid)
-    return __pack_envs[packid]
-end
-__vc__pack_envs = nil
-
 function require(path)
     if not string.find(path, ':') then
         local prefix, _ = parse_path(_debug_getinfo(2).source)