fs: do not cache cfg.variables

Avoid relying on the order that cfg and fs are required.

This is not strictly required in regular operation, but it
allows us to mock cfg and use fs.

3 files changed, 21 insertions, 25 deletions

diff --git a/src/luarocks/fs/tools.lua b/src/luarocks/fs/tools.lua
index 671c7ae1..8f4dd1a5 100644
--- a/src/luarocks/fs/tools.lua
+++ b/src/luarocks/fs/tools.lua
@@ -6,7 +6,7 @@ local fs = require("luarocks.fs")
 local dir = require("luarocks.dir")
 local cfg = require("luarocks.core.cfg")
 
-local vars = cfg.variables
+local vars = setmetatable({}, { __index = function(_,k) return cfg.variables[k] end })
 
 local dir_stack = {}
 
@@ -20,23 +20,26 @@ do
       },
       md5checker = {
          { var = "MD5SUM", name = "md5sum" },
-         { var = "OPENSSL", name = "openssl" },
-         { var = "MD5", name = "md5", arg = "-v" },
+         { var = "OPENSSL", name = "openssl", cmdarg = "md5" },
+         { var = "MD5", name = "md5", checkarg = "-v" },
       },
    }
-   
+
    function tools.which_tool(tooltype)
-      if tool_cache[tooltype] then
-         return tool_cache[tooltype]
-      end
-      
-      for _, opt in ipairs(tool_options[tooltype]) do
-         if fs.is_tool_available(vars[opt.var], opt.name, opt.arg) then
-            tool_cache[tooltype] = opt.name
-            break
+      local tool = tool_cache[tooltype]
+      if not tool then
+         for _, opt in ipairs(tool_options[tooltype]) do
+            if fs.is_tool_available(vars[opt.var], opt.name, opt.checkarg) then
+               tool = opt
+               tool_cache[tooltype] = opt
+               break
+            end
          end
       end
-      return tool_cache[tooltype]
+      if not tool then
+         return nil
+      end
+      return tool.name, fs.Q(vars[tool.var]) .. (tool.cmdarg and " "..tool.cmdarg or "")
    end
 end
 
@@ -169,20 +172,13 @@ function tools.use_downloader(url, filename, cache)
    end
 end
 
-local md5_cmd = {
-   md5sum = fs.Q(vars.MD5SUM),
-   openssl = fs.Q(vars.OPENSSL).." md5",
-   md5 = fs.Q(vars.MD5),
-}
-
 --- Get the MD5 checksum for a file.
 -- @param file string: The file to be computed.
 -- @return string: The MD5 checksum or nil + message
 function tools.get_md5(file)
-   local md5checker = fs.which_tool("md5checker")
-   if md5checker then
-      local cmd = md5_cmd[md5checker]
-      local pipe = io.popen(cmd.." "..fs.Q(fs.absolute_name(file)))
+   local ok, md5checker = fs.which_tool("md5checker")
+   if ok then
+      local pipe = io.popen(md5checker.." "..fs.Q(fs.absolute_name(file)))
       local computed = pipe:read("*l")
       pipe:close()
       if computed then
diff --git a/src/luarocks/fs/unix/tools.lua b/src/luarocks/fs/unix/tools.lua
index e0b0d22a..6a91775f 100644
--- a/src/luarocks/fs/unix/tools.lua
+++ b/src/luarocks/fs/unix/tools.lua
@@ -6,7 +6,7 @@ local fs = require("luarocks.fs")
 local dir = require("luarocks.dir")
 local cfg = require("luarocks.core.cfg")
 
-local vars = cfg.variables
+local vars = setmetatable({}, { __index = function(_,k) return cfg.variables[k] end })
 
 --- Adds prefix to command to make it run from a directory.
 -- @param directory string: Path to a directory.
diff --git a/src/luarocks/fs/win32/tools.lua b/src/luarocks/fs/win32/tools.lua
index d0a7d8b2..c03b0d7b 100644
--- a/src/luarocks/fs/win32/tools.lua
+++ b/src/luarocks/fs/win32/tools.lua
@@ -8,7 +8,7 @@ local fs = require("luarocks.fs")
 local dir = require("luarocks.dir")
 local cfg = require("luarocks.core.cfg")
 
-local vars = cfg.variables
+local vars = setmetatable({}, { __index = function(_,k) return cfg.variables[k] end })
 
 --- Adds prefix to command to make it run from a directory.
 -- @param directory string: Path to a directory.