cmd: fix setting up deployment paths from a tree

(Amended with a regression test.)

Co-authored-by: Hisham Muhammad <hisham@gobolinux.org>

2 files changed, 22 insertions, 5 deletions

diff --git a/spec/config_spec.lua b/spec/config_spec.lua
index f415909d..defc1d2f 100644
--- a/spec/config_spec.lua
+++ b/spec/config_spec.lua
@@ -3,6 +3,7 @@ local lfs = require("lfs")
 local run = test_env.run
 local testing_paths = test_env.testing_paths
 local env_variables = test_env.env_variables
+local write_file = test_env.write_file
 local hardcoded
 
 test_env.unload_luarocks()
@@ -52,6 +53,22 @@ describe("LuaRocks config tests #integration", function()
          local output = run.luarocks("config --user-config", {LUAROCKS_CONFIG = "missing_file.lua"})
          assert.truthy(output:match("Warning"))
       end)
+
+      it("LuaRocks config with --tree respects custom config", function()
+         write_file("my_config.lua", [[
+            rocks_trees = {
+               {
+                  name = "system",
+                  root = "/example/tree",
+                  lua_dir = "/example/luadir",
+               },
+            }
+         ]], finally)
+         local output = run.luarocks("config", {LUAROCKS_CONFIG = "my_config.lua"})
+         assert.match([[deploy_lua_dir = "/example/luadir"]], output)
+         output = run.luarocks("config --tree=system", {LUAROCKS_CONFIG = "my_config.lua"})
+         assert.match([[deploy_lua_dir = "/example/luadir"]], output)
+      end)
    end)
 
    describe("LuaRocks config - more complex tests", function()
diff --git a/src/luarocks/cmd.lua b/src/luarocks/cmd.lua
index fc98e45f..996900ff 100644
--- a/src/luarocks/cmd.lua
+++ b/src/luarocks/cmd.lua
@@ -150,10 +150,10 @@ end
 
 local process_tree_flags
 do
-   local function replace_tree(flags, tree)
-      tree = dir.normalize(tree)
-      flags["tree"] = tree
-      path.use_tree(tree)
+   local function replace_tree(flags, root, tree)
+      root = dir.normalize(root)
+      flags["tree"] = root
+      path.use_tree(tree or root)
    end
 
    local function find_project_dir()
@@ -195,7 +195,7 @@ do
                if not tree.root then
                   return nil, "Configuration error: tree '"..tree.name.."' has no 'root' field."
                end
-               replace_tree(flags, tree.root)
+               replace_tree(flags, tree.root, tree)
                named = true
                break
             end