Fix crash when --lua-version is malformed

2 files changed, 6 insertions, 0 deletions

diff --git a/spec/cmd_spec.lua b/spec/cmd_spec.lua
index d28acdf6..fe27ab1b 100644
--- a/spec/cmd_spec.lua
+++ b/spec/cmd_spec.lua
@@ -53,6 +53,11 @@ describe("LuaRocks command line #integration", function()
    end)
 
    describe("--lua-version", function()
+      it("fails if given something that is not a number", function()
+         local output = run.luarocks("--lua-version=bozo")
+         assert.match("malformed", output, 1, true)
+      end)
+
       it("warns but continues if given an invalid version", function()
          local output = run.luarocks("--lua-version=1.0")
          assert.match("Warning: Lua 1.0 interpreter not found", output, 1, true)
diff --git a/src/luarocks/cmd.lua b/src/luarocks/cmd.lua
index 233bb1bd..962d9256 100644
--- a/src/luarocks/cmd.lua
+++ b/src/luarocks/cmd.lua
@@ -463,6 +463,7 @@ Enabling completion for Fish:
       :argname("<prefix>")
    parser:option("--lua-version", "Which Lua version to use.")
       :argname("<ver>")
+      :convert(function(s) return (s:match("^%d+%.%d+$")) end)
    parser:option("--tree", "Which tree to operate on.")
       :hidden_name("--to")
    parser:flag("--local", "Use the tree in the user's home directory.\n"..