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diff --git a/src/luarocks/loader.lua b/src/luarocks/loader.lua
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+--- A module which installs a Lua package loader that is LuaRocks-aware.
+-- This loader uses dependency information from the LuaRocks tree to load
+-- correct versions of modules. It does this by constructing a "context"
+-- table in the environment, which records which versions of packages were
+-- used to load previous modules, so that the loader chooses versions
+-- that are declared to be compatible with the ones loaded earlier.
+
+-- luacheck: globals luarocks
+
+local loaders = package.loaders or package.searchers
+local require, ipairs, table, type, next, tostring, error =
+      require, ipairs, table, type, next, tostring, error
+local unpack = unpack or table.unpack
+
+local loader = {}
+
+local is_clean = not package.loaded["luarocks.core.cfg"]
+
+-- This loader module depends only on core modules.
+local cfg = require("luarocks.core.cfg")
+local cfg_ok, err = cfg.init()
+if cfg_ok then
+   cfg.init_package_paths()
+end
+
+local path = require("luarocks.core.path")
+local manif = require("luarocks.core.manif")
+local vers = require("luarocks.core.vers")
+local require = nil  -- luacheck: ignore 411
+--------------------------------------------------------------------------------
+
+-- Workaround for wrappers produced by older versions of LuaRocks
+local temporary_global = false
+local status, luarocks_value = pcall(function() return luarocks end)
+if status and luarocks_value then
+   -- The site_config.lua file generated by old versions uses module(),
+   -- so it produces a global `luarocks` table. Since we have the table,
+   -- add the `loader` field to make the old wrappers happy.
+   luarocks.loader = loader
+else
+   -- When a new version is installed on top of an old version,
+   -- site_config.lua may be replaced, and then it no longer creates
+   -- a global.
+   -- Detect when being called via -lluarocks.loader; this is
+   -- most likely a wrapper.
+   local info = debug and debug.getinfo(2, "nS")
+   if info and info.what == "C" and not info.name then
+      luarocks = { loader = loader }
+      temporary_global = true
+      -- For the other half of this hack,
+      -- see the next use of `temporary_global` below.
+   end
+end
+
+loader.context = {}
+
+--- Process the dependencies of a package to determine its dependency
+-- chain for loading modules.
+-- @param name string: The name of an installed rock.
+-- @param version string: The version of the rock, in string format
+function loader.add_context(name, version)
+   -- assert(type(name) == "string")
+   -- assert(type(version) == "string")
+
+   if temporary_global then
+      -- The first thing a wrapper does is to call add_context.
+      -- From here on, it's safe to clean the global environment.
+      luarocks = nil
+      temporary_global = false
+   end
+
+   local tree_manifests = manif.load_rocks_tree_manifests()
+   if not tree_manifests then
+      return nil
+   end
+
+   return manif.scan_dependencies(name, version, tree_manifests, loader.context)
+end
+
+--- Internal sorting function.
+-- @param a table: A provider table.
+-- @param b table: Another provider table.
+-- @return boolean: True if the version of a is greater than that of b.
+local function sort_versions(a,b)
+   return a.version > b.version
+end
+
+--- Request module to be loaded through other loaders,
+-- once the proper name of the module has been determined.
+-- For example, in case the module "socket.core" has been requested
+-- to the LuaRocks loader and it determined based on context that
+-- the version 2.0.2 needs to be loaded and it is not the current
+-- version, the module requested for the other loaders will be
+-- "socket.core_2_0_2".
+-- @param module The module name requested by the user, such as "socket.core"
+-- @param name The rock name, such as "luasocket"
+-- @param version The rock version, such as "2.0.2-1"
+-- @param module_name The actual module name, such as "socket.core" or "socket.core_2_0_2".
+-- @return table or (nil, string): The module table as returned by some other loader,
+-- or nil followed by an error message if no other loader managed to load the module.
+local function call_other_loaders(module, name, version, module_name)
+   for _, a_loader in ipairs(loaders) do
+      if a_loader ~= loader.luarocks_loader then
+         local results = { a_loader(module_name) }
+         if type(results[1]) == "function" then
+            return unpack(results)
+         end
+      end
+   end
+   return "Failed loading module "..module.." in LuaRocks rock "..name.." "..version
+end
+
+local function add_providers(providers, entries, tree, module, filter_file_name)
+   for i, entry in ipairs(entries) do
+      local name, version = entry:match("^([^/]*)/(.*)$")
+      local file_name = tree.manifest.repository[name][version][1].modules[module]
+      if type(file_name) ~= "string" then
+         error("Invalid data in manifest file for module "..tostring(module).." (invalid data for "..tostring(name).." "..tostring(version)..")")
+      end
+      file_name = filter_file_name(file_name, name, version, tree.tree, i)
+      if loader.context[name] == version then
+         return name, version, file_name
+      end
+      version = vers.parse_version(version)
+      table.insert(providers, {name = name, version = version, module_name = file_name, tree = tree})
+   end
+end
+
+--- Search for a module in the rocks trees
+-- @param module string: module name (eg. "socket.core")
+-- @param filter_file_name function(string, string, string, string, number):
+-- a function that takes the module file name (eg "socket/core.so"), the rock name
+-- (eg "luasocket"), the version (eg "2.0.2-1"), the path of the rocks tree
+-- (eg "/usr/local"), and the numeric index of the matching entry, so the
+-- filter function can know if the matching module was the first entry or not.
+-- @return string, string, string, (string or table):
+-- * name of the rock containing the module (eg. "luasocket")
+-- * version of the rock (eg. "2.0.2-1")
+-- * return value of filter_file_name
+-- * tree of the module (string or table in `tree_manifests` format)
+local function select_module(module, filter_file_name)
+   --assert(type(module) == "string")
+   --assert(type(filter_module_name) == "function")
+
+   local tree_manifests = manif.load_rocks_tree_manifests()
+   if not tree_manifests then
+      return nil
+   end
+
+   local providers = {}
+   local initmodule
+   for _, tree in ipairs(tree_manifests) do
+      local entries = tree.manifest.modules[module]
+      if entries then
+         local n, v, f = add_providers(providers, entries, tree, module, filter_file_name)
+         if n then
+            return n, v, f
+         end
+      else
+         initmodule = initmodule or module .. ".init"
+         entries = tree.manifest.modules[initmodule]
+         if entries then
+            local n, v, f = add_providers(providers, entries, tree, initmodule, filter_file_name)
+            if n then
+               return n, v, f
+            end
+         end
+      end
+   end
+
+   if next(providers) then
+      table.sort(providers, sort_versions)
+      local first = providers[1]
+      return first.name, first.version.string, first.module_name, first.tree
+   end
+end
+
+--- Search for a module
+-- @param module string: module name (eg. "socket.core")
+-- @return string, string, string, (string or table):
+-- * name of the rock containing the module (eg. "luasocket")
+-- * version of the rock (eg. "2.0.2-1")
+-- * name of the module (eg. "socket.core", or "socket.core_2_0_2" if file is stored versioned).
+-- * tree of the module (string or table in `tree_manifests` format)
+local function pick_module(module)
+   return
+      select_module(module, function(file_name, name, version, tree, i)
+         if i > 1 then
+            file_name = path.versioned_name(file_name, "", name, version)
+         end
+         return path.path_to_module(file_name)
+      end)
+end
+
+--- Return the pathname of the file that would be loaded for a module.
+-- @param module string: module name (eg. "socket.core")
+-- @param where string: places to look for the module. If `where` contains
+-- "l", it will search using the LuaRocks loader; if it contains "p",
+-- it will look in the filesystem using package.path and package.cpath.
+-- You can use both at the same time.
+-- @return If successful, it will return four values.
+-- * If found using the LuaRocks loader, it will return:
+--   * filename of the module (eg. "/usr/local/lib/lua/5.1/socket/core.so"),
+--   * rock name
+--   * rock version
+--   * "l" to indicate the match comes from the loader.
+-- * If found scanning package.path and package.cpath, it will return:
+--   * filename of the module (eg. "/usr/local/lib/lua/5.1/socket/core.so"),
+--   * "path" or "cpath"
+--   * nil
+--   * "p" to indicate the match comes from scanning package.path and cpath.
+-- If unsuccessful, nothing is returned.
+function loader.which(module, where)
+   where = where or "l"
+   if where:match("l") then
+      local rock_name, rock_version, file_name = select_module(module, path.which_i)
+      if rock_name then
+         local fd = io.open(file_name)
+         if fd then
+            fd:close()
+            return file_name, rock_name, rock_version, "l"
+         end
+      end
+   end
+   if where:match("p") then
+      local modpath = module:gsub("%.", "/")
+      for _, v in ipairs({"path", "cpath"}) do
+         for p in package[v]:gmatch("([^;]+)") do
+            local file_name = p:gsub("%?", modpath)  -- luacheck: ignore 421
+            local fd = io.open(file_name)
+            if fd then
+               fd:close()
+               return file_name, v, nil, "p"
+            end
+         end
+      end
+   end
+end
+
+--- Package loader for LuaRocks support.
+-- A module is searched in installed rocks that match the
+-- current LuaRocks context. If module is not part of the
+-- context, or if a context has not yet been set, the module
+-- in the package with the highest version is used.
+-- @param module string: The module name, like in plain require().
+-- @return table: The module table (typically), like in plain
+-- require(). See <a href="http://www.lua.org/manual/5.1/manual.html#pdf-require">require()</a>
+-- in the Lua reference manual for details.
+function loader.luarocks_loader(module)
+   local name, version, module_name = pick_module(module)
+   if not name then
+      return "No LuaRocks module found for "..module
+   else
+      loader.add_context(name, version)
+      return call_other_loaders(module, name, version, module_name)
+   end
+end
+
+table.insert(loaders, 1, loader.luarocks_loader)
+
+if is_clean then
+   for modname, _ in pairs(package.loaded) do
+      if modname:match("^luarocks%.") then
+         package.loaded[modname] = nil
+      end
+   end
+end
+
+return loader