Make formspec_ast.flatten ignore scroll containers

helpers.lua

@@ -42,9 +42,7 @@ function formspec_ast.interpret(spec, custom_handlers)
     return formspec_ast.unparse(ast)
 end
 
--- Returns an iterator over all nodes in a formspec AST, including ones in
+local function walk_inner(tree, container_elems)
--- containers.
-function formspec_ast.walk(tree)
     local parents = {}
     local i = 1
     return function()
@@ -59,7 +57,7 @@ function formspec_ast.walk(tree)
         end
         i = i + 1
 
-        if res.type == 'container' or res.type == 'scroll_container' then
+        if container_elems[res.type] then
             table.insert(parents, {tree, i})
             tree = res
             i = 1
@@ -68,6 +66,13 @@ function formspec_ast.walk(tree)
     end
 end
 
+-- Returns an iterator over all nodes in a formspec AST, including ones in
+-- containers.
+local container_elems = {container = true, scroll_container = true}
+function formspec_ast.walk(tree)
+    return walk_inner(tree, container_elems)
+end
+
 -- Similar to formspec_ast.walk(), however only returns nodes which have a type
 -- of `node_type`.
 function formspec_ast.find(tree, node_type)
@@ -114,9 +119,10 @@ function formspec_ast.apply_offset(elems, x, y)
 end
 
 -- Removes container elements and fixes nodes inside containers.
+local flatten_containers = {container = true}
 function formspec_ast.flatten(tree)
     local res = {formspec_version=tree.formspec_version}
-    for elem in formspec_ast.walk(table.copy(tree)) do
+    for elem in walk_inner(table.copy(tree), flatten_containers) do
         if elem.type == 'container' then
             formspec_ast.apply_offset(elem, elem.x, elem.y)
         else

tests.lua

@@ -345,4 +345,21 @@ assert_equal(
     }))
 )
 
+-- Ensure flatten works correctly
+assert_equal(
+    'label[0,0;abc]label[2,2;def]scroll_container[1,1;2,2;test;vertical]' ..
+        'image[1,1;1,1;def]scroll_container_end[]',
+    formspec_ast.unparse(formspec_ast.flatten(assert(formspec_ast.parse([[
+        label[0,0;abc]
+        container[3,2]
+            container[-1,0]
+                label[0,0;def]
+            container_end[]
+        container_end[]
+        scroll_container[1,1;2,2;test;vertical]
+            image[1,1;1,1;def]
+        scroll_container_end[]
+    ]]))))
+)
+
 print('Tests pass')