fs: make module loading side-effect free, require explicit init()

4 files changed, 72 insertions, 49 deletions

diff --git a/src/luarocks/command_line.lua b/src/luarocks/command_line.lua
index 5ba5ae1b..b542fb9c 100644
--- a/src/luarocks/command_line.lua
+++ b/src/luarocks/command_line.lua
@@ -93,6 +93,8 @@ function command_line.run_command(...)
       die(flags.ERROR.." See --help.")
    end
    
+   fs.init()
+
    if flags["from"] then flags["server"] = flags["from"] end
    if flags["only-from"] then flags["only-server"] = flags["only-from"] end
    if flags["only-sources-from"] then flags["only-sources"] = flags["only-sources-from"] end
diff --git a/src/luarocks/core/cfg.lua b/src/luarocks/core/cfg.lua
index 38b10f6e..00efeaf3 100644
--- a/src/luarocks/core/cfg.lua
+++ b/src/luarocks/core/cfg.lua
@@ -763,4 +763,12 @@ function cfg.is_platform(query)
    end
 end
 
+function cfg.each_platform()
+   local i = 0
+   return function()
+      i = i + 1
+      return cfg.platforms[i]
+   end
+end
+
 return cfg
diff --git a/src/luarocks/fs.lua b/src/luarocks/fs.lua
index 7322e552..999572b8 100644
--- a/src/luarocks/fs.lua
+++ b/src/luarocks/fs.lua
@@ -16,62 +16,73 @@ local cfg = require("luarocks.core.cfg")
 local pack = table.pack or function(...) return { n = select("#", ...), ... } end
 local unpack = table.unpack or unpack
 
-local old_popen, old_exec
-fs.verbose = function()    -- patch io.popen and os.execute to display commands in verbose mode
-  if old_popen or old_exec then return end
-  old_popen = io.popen
-  io.popen = function(one, two)
-    if two == nil then
-      print("\nio.popen: ", one)
-    else
-      print("\nio.popen: ", one, "Mode:", two)
-    end
-    return old_popen(one, two)
-  end
-  
-  old_exec = os.execute
-  os.execute = function(cmd)
-    -- redact api keys if present
-    print("\nos.execute: ", (cmd:gsub("(/api/[^/]+/)([^/]+)/", function(cap, key) return cap.."<redacted>/" end)) )
-    local code = pack(old_exec(cmd))
-    print("Results: "..tostring(code.n))
-    for i = 1,code.n do
-      print("  "..tostring(i).." ("..type(code[i]).."): "..tostring(code[i]))
-    end
-    return unpack(code, 1, code.n)    
-  end
-end
-if cfg.verbose then fs.verbose() end
+do
+   local old_popen, old_execute
+
+   -- patch io.popen and os.execute to display commands in verbose mode
+   function fs.verbose()
+      if old_popen or old_execute then return end
+      old_popen = io.popen
+      io.popen = function(one, two)
+         if two == nil then
+            print("\nio.popen: ", one)
+         else
+            print("\nio.popen: ", one, "Mode:", two)
+         end
+         return old_popen(one, two)
+      end
 
-local function load_fns(fs_table)
-   for name, fn in pairs(fs_table) do
-      if not fs[name] then
-         fs[name] = fn
+      old_execute = os.execute
+      os.execute = function(cmd)
+         -- redact api keys if present
+         print("\nos.execute: ", (cmd:gsub("(/api/[^/]+/)([^/]+)/", function(cap, key) return cap.."<redacted>/" end)) )
+         local code = pack(old_execute(cmd))
+         print("Results: "..tostring(code.n))
+         for i = 1,code.n do
+            print("  "..tostring(i).." ("..type(code[i]).."): "..tostring(code[i]))
+         end
+         return unpack(code, 1, code.n)
       end
    end
 end
 
--- Load platform-specific functions
-local loaded_platform = nil
-for _, platform in ipairs(cfg.platforms) do
-   local ok, fs_plat = pcall(require, "luarocks.fs."..platform)
-   if ok and fs_plat then
-      loaded_platform = platform
-      load_fns(fs_plat)
-      break
+do
+   local function load_fns(fs_table)
+      for name, fn in pairs(fs_table) do
+         if not fs[name] then
+            fs[name] = fn
+         end
+      end
    end
-end
 
--- Load platform-independent pure-Lua functionality
-local fs_lua = require("luarocks.fs.lua")
-load_fns(fs_lua)
+   function fs.init()
+      if fs.current_dir then
+         -- already initialized
+         return
+      end
+
+      -- Load platform-specific functions
+      local loaded_platform = nil
+      for platform in cfg.each_platform() do
+         local ok, fs_plat = pcall(require, "luarocks.fs."..platform)
+         if ok and fs_plat then
+            loaded_platform = platform
+            load_fns(fs_plat)
+            break
+         end
+      end
 
--- Load platform-specific fallbacks for missing Lua modules
-local ok, fs_plat_tools = pcall(require, "luarocks.fs."..loaded_platform..".tools")
-if ok and fs_plat_tools then
-   load_fns(fs_plat_tools)
-   load_fns(require("luarocks.fs.tools"))
-end
+      -- Load platform-independent pure-Lua functionality
+      local fs_lua = require("luarocks.fs.lua")
+      load_fns(fs_lua)
 
+      -- Load platform-specific fallbacks for missing Lua modules
+      local ok, fs_plat_tools = pcall(require, "luarocks.fs."..loaded_platform..".tools")
+      if ok and fs_plat_tools then
+         load_fns(fs_plat_tools)
+         load_fns(require("luarocks.fs.tools"))
+      end
+   end
+end
 
 return fs
diff --git a/src/luarocks/util.lua b/src/luarocks/util.lua
index ee4a803a..8058a407 100644
--- a/src/luarocks/util.lua
+++ b/src/luarocks/util.lua
@@ -59,7 +59,9 @@ end
 -- Functions are executed in the inverse order they were scheduled.
 function util.run_scheduled_functions()
    local fs = require("luarocks.fs")
-   fs.change_dir_to_root()
+   if fs.change_dir_to_root then
+      fs.change_dir_to_root()
+   end
    for i = #scheduled_functions, 1, -1 do
       local item = scheduled_functions[i]
       item.fn(unpack(item.args))