path: use versioned LUA_xPATH_5_x variables

`luarocks path` now exports versioned variables `LUA_PATH_5_x` and
`LUA_CPATH_5_x` instead of `LUA_PATH` and `LUA_CPATH`
when those are in use in your system.

Fixes #760.

6 files changed, 62 insertions, 9 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6d028713..0bd8c0c0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,9 @@
 What's new in LuaRocks 3.0
 ==========================
 
+* `luarocks path` now exports versioned variables `LUA_PATH_5_x` and
+  `LUA_CPATH_5_x` instead of `LUA_PATH` and `LUA_CPATH`
+  when those are in use in your system.
 * Package paths are sanitized to only reference the current Lua version.
   For example, if you have `/some/dir/lua/5.1/` in your `$LUA_PATH` and
   you are running Lua 5.2, `luarocks.loader` and the `luarocks` command-line
diff --git a/spec/path_spec.lua b/spec/path_spec.lua
index 22f07591..536233b1 100644
--- a/spec/path_spec.lua
+++ b/spec/path_spec.lua
@@ -8,6 +8,40 @@ describe("LuaRocks path tests #blackbox #b_path", function()
       test_env.setup_specs()
    end)
 
+   it("LuaRocks path", function()
+      local output = run.luarocks("path")
+      assert.match("LUA_PATH=", output)
+      assert.match("LUA_CPATH=", output)
+   end)
+
+   if _VERSION:match("[23]") then
+      local v = _VERSION:gsub("Lua (%d+)%.(%d+)", "%1_%2")
+   
+      it("LuaRocks path with LUA_PATH_"..v, function()
+         local output = run.luarocks("path", {
+            ["LUA_PATH_"..v] = package.path,
+         })
+         assert.match("LUA_PATH_"..v.."=", output)
+      end)
+
+      it("LuaRocks path with LUA_CPATH_"..v, function()
+         local output = run.luarocks("path", {
+            ["LUA_CPATH_"..v] = package.cpath,
+         })
+         assert.match("LUA_CPATH_"..v.."=", output)
+      end)
+
+      it("LuaRocks path with LUA_PATH_"..v.." and LUA_CPATH_"..v, function()
+         local output = run.luarocks("path", {
+            ["LUA_PATH_"..v]  = package.path,
+            ["LUA_CPATH_"..v] = package.cpath,
+         })
+         assert.match("LUA_PATH_"..v.."=", output)
+         assert.match("LUA_CPATH_"..v.."=", output)
+      end)
+
+   end
+
    it("LuaRocks path bin", function()
       assert.is_true(run.luarocks_bool("path --bin"))
    end)
diff --git a/src/luarocks/cmd/path.lua b/src/luarocks/cmd/path.lua
index 3cf43091..9bcd1c81 100644
--- a/src/luarocks/cmd/path.lua
+++ b/src/luarocks/cmd/path.lua
@@ -5,6 +5,7 @@ local path_cmd = {}
 
 local util = require("luarocks.util")
 local cfg = require("luarocks.core.cfg")
+local fs = require("luarocks.fs")
 
 path_cmd.help_summary = "Return the currently configured package path."
 path_cmd.help_arguments = ""
@@ -56,11 +57,24 @@ function path_cmd.command(flags)
       lr_cpath = lr_cpath .. ";" .. package.cpath
       lr_bin = lr_bin .. path_sep .. os.getenv("PATH")
    end
+   
+   local lpath_var = "LUA_PATH"
+   local lcpath_var = "LUA_CPATH"
+   
+   local lv = cfg.lua_version:gsub("%.", "_")
+   if lv ~= "5_1" then
+      if os.getenv("LUA_PATH_" .. lv) then
+         lpath_var = "LUA_PATH_" .. lv
+      end
+      if os.getenv("LUA_CPATH_" .. lv) then
+         lcpath_var = "LUA_CPATH_" .. lv
+      end
+   end
 
-   util.printout(cfg.export_lua_path:format(util.cleanup_path(lr_path, ';', cfg.lua_version)))
-   util.printout(cfg.export_lua_cpath:format(util.cleanup_path(lr_cpath, ';', cfg.lua_version)))
+   util.printout(fs.export_cmd(lpath_var, util.cleanup_path(lr_path, ';', cfg.lua_version)))
+   util.printout(fs.export_cmd(lcpath_var, util.cleanup_path(lr_cpath, ';', cfg.lua_version)))
    if flags["bin"] then
-      util.printout(cfg.export_path:format(util.cleanup_path(lr_bin, path_sep)))
+      util.printout(fs.export_cmd("PATH", util.cleanup_path(lr_bin, path_sep)))
    end
    return true
 end
diff --git a/src/luarocks/core/cfg.lua b/src/luarocks/core/cfg.lua
index e6351add..3326375f 100644
--- a/src/luarocks/core/cfg.lua
+++ b/src/luarocks/core/cfg.lua
@@ -473,10 +473,7 @@ if cfg.platforms.windows then
       lib = { "?.dll", "lib?.dll" },
       include = { "?.h" }
    }
-   defaults.export_path = "SET PATH=%s"
    defaults.export_path_separator = ";"
-   defaults.export_lua_path = "SET LUA_PATH=%s"
-   defaults.export_lua_cpath = "SET LUA_CPATH=%s"
    defaults.wrapper_suffix = ".bat"
 
    local localappdata = os.getenv("LOCALAPPDATA")
@@ -541,10 +538,7 @@ if cfg.platforms.unix then
       lib = { "lib?.so", "lib?.so.*" },
       include = { "?.h" }
    }
-   defaults.export_path = "export PATH='%s'"
    defaults.export_path_separator = ":"
-   defaults.export_lua_path = "export LUA_PATH='%s'"
-   defaults.export_lua_cpath = "export LUA_CPATH='%s'"
    defaults.wrapper_suffix = ""
    defaults.local_cache = cfg.home.."/.cache/luarocks"
    if not defaults.variables.CFLAGS:match("-fPIC") then
diff --git a/src/luarocks/fs/unix.lua b/src/luarocks/fs/unix.lua
index 52634246..c99e1566 100644
--- a/src/luarocks/fs/unix.lua
+++ b/src/luarocks/fs/unix.lua
@@ -136,4 +136,8 @@ function unix.current_user()
    return os.getenv("USER")
 end
 
+function unix.export_cmd(var, val)
+   return ("export %s='%s'"):format(var, val)
+end
+
 return unix
diff --git a/src/luarocks/fs/win32.lua b/src/luarocks/fs/win32.lua
index 92068e39..6fd24fa5 100644
--- a/src/luarocks/fs/win32.lua
+++ b/src/luarocks/fs/win32.lua
@@ -272,4 +272,8 @@ function win32.current_user()
    return os.getenv("USERNAME")
 end
 
+function win32.export_cmd(var, val)
+   return ("SET %s=%s"):format(var, val)
+end
+
 return win32