root tracking for macro components (#3882)

* root tracking for macro components

Closes #3877.

* prune text after empty macro component

* remove prune_text_after_slot

Author: SteffenDE

lib/phoenix_live_view/tag_engine.ex

@@ -363,10 +363,13 @@ defmodule Phoenix.LiveView.TagEngine do
     %{state | slots: [[slot | slots] | other_slots]}
   end
 
-  defp prune_text_after_slot([{:text, text, meta} | tokens]),
+  defp maybe_prune_text_after_macro_component("", tokens), do: prune_text(tokens)
+  defp maybe_prune_text_after_macro_component(_ast, tokens), do: tokens
+
+  defp prune_text([{:text, text, meta} | tokens]),
     do: [{:text, String.trim_leading(text), meta} | tokens]
 
-  defp prune_text_after_slot(tokens),
+  defp prune_text(tokens),
     do: tokens
 
   defp validate_slot!(%{tags: [{type, _, _, _} | _]}, _name, _tag_meta)
@@ -424,6 +427,11 @@ defmodule Phoenix.LiveView.TagEngine do
     %{state | tags: [token | state.tags]}
   end
 
+  # special clause for macro components
+  defp pop_tag!(%{tags: [{:macro_tag, name} | tags]} = state, {:close, :macro_tag, name}) do
+    %{state | tags: tags}
+  end
+
   defp pop_tag!(
          %{tags: [{type, tag_name, _attrs, _meta} = tag | tags]} = state,
          {:close, type, tag_name, _}
@@ -623,7 +631,7 @@ defmodule Phoenix.LiveView.TagEngine do
     assigns = wrap_special_slot(special, merge_component_attrs(roots, attrs, line))
 
     add_slot(state, slot_name, assigns, attr_info, tag_meta, special)
-    |> continue(prune_text_after_slot(tokens))
+    |> continue(prune_text(tokens))
   end
 
   # Slot (with inner content)
@@ -659,7 +667,7 @@ defmodule Phoenix.LiveView.TagEngine do
     state
     |> add_slot(slot_name, assigns, inner, tag_meta, special)
     |> pop_substate_from_stack()
-    |> continue(prune_text_after_slot(tokens))
+    |> continue(prune_text(tokens))
   end
 
   # Local function component (self close)
@@ -859,11 +867,6 @@ defmodule Phoenix.LiveView.TagEngine do
 
     module = validate_module!(module_string, tag_meta, state)
 
-    # we do not perform root tracking on macro components
-    # but we call set_root_on_not_tag since a macro component could be
-    # just some text without any tags
-    state = set_root_on_not_tag(state)
-
     try do
       {ast, rest} =
         case Phoenix.Component.MacroComponent.build_ast(tokens, state.caller) do
@@ -883,14 +886,14 @@ defmodule Phoenix.LiveView.TagEngine do
       {{:ok, new_ast}, rest} ->
         state
         |> handle_ast(new_ast, tag_meta)
-        |> continue(rest)
+        |> continue(maybe_prune_text_after_macro_component(new_ast, rest))
 
       {{:ok, new_ast, data}, rest} ->
         Module.put_attribute(state.caller.module, :__macro_components__, {module, data})
 
         state
         |> handle_ast(new_ast, tag_meta)
-        |> continue(rest)
+        |> continue(maybe_prune_text_after_macro_component(new_ast, rest))
 
       {other, _rest} ->
         raise ArgumentError,
@@ -907,22 +910,30 @@ defmodule Phoenix.LiveView.TagEngine do
       end
 
     state
+    |> set_root_on_tag()
     |> update_subengine(:handle_text, [[], "<#{tag}"])
     |> handle_ast_attrs(attrs, tag_open_meta)
     |> update_subengine(:handle_text, [[], suffix])
   end
 
   defp handle_ast(state, {tag, attrs, children, _meta}, tag_open_meta) do
     state
+    |> set_root_on_tag()
+    |> push_tag({:macro_tag, tag})
     |> update_subengine(:handle_text, [[], "<#{tag}"])
     |> handle_ast_attrs(attrs, tag_open_meta)
     |> update_subengine(:handle_text, [[], ">"])
     |> handle_ast(children, tag_open_meta)
     |> update_subengine(:handle_text, [[], "</#{tag}>"])
+    |> pop_tag!({:close, :macro_tag, tag})
   end
 
+  defp handle_ast(state, "", _tag_open_meta), do: state
+
   defp handle_ast(state, text, _tag_open_meta) when is_binary(text) do
-    update_subengine(state, :handle_text, [[], text])
+    state
+    |> set_root_on_not_tag()
+    |> update_subengine(:handle_text, [[], text])
   end
 
   defp handle_ast(state, children, tag_open_meta) when is_list(children) do

test/phoenix_component/macro_component_integration_test.exs

@@ -311,35 +311,52 @@ defmodule Phoenix.Component.MacroComponentIntegrationTest do
     assert Enum.find(data, fn %{opts: opts} -> opts == %{"id" => "2"} end)
   end
 
-  describe "root tracking" do
-    @endpoint Phoenix.LiveViewTest.Support.Endpoint
-
-    test "does not count as root" do
-      defmodule TestLVDoesNotCountAsRoot do
-        use Phoenix.LiveView
-
-        defmodule LC do
-          use Phoenix.LiveComponent
-
-          def render(assigns) do
-            ~H"""
-            <div :type={MyComponent}></div>
-            """
-          end
-        end
-
-        def render(assigns) do
-          ~H"""
-          <.live_component module={LC} id="my-lc" />
-          """
-        end
-      end
+  test "root tracking" do
+    assert eval_heex("<div :type={MyComponent}>Test</div>").root
 
-      assert_raise ArgumentError,
-                   ~r/Stateful components must have a single static HTML tag at the root/,
-                   fn ->
-                     live_isolated(Phoenix.ConnTest.build_conn(), TestLVDoesNotCountAsRoot)
-                   end
-    end
+    refute eval_heex("""
+           <div :type={MyComponent}>Test</div>
+           <span>Another</span>
+           """).root
+
+    Process.put(
+      :new_ast,
+      {:div, [{"id", "1"}],
+       [
+         {"span", [{"class", "\"foo\""}], ["Test"], %{}},
+         {"span", [{"class", "'foo'"}], ["Test"], %{}}
+       ], %{}}
+    )
+
+    assert eval_heex("<div :type={MyComponent}>Test</div>").root
+
+    Process.put(:new_ast, "")
+
+    assert eval_heex("""
+           <div :type={MyComponent}>Test</div><span>Another</span>
+           """).root
+
+    Process.put(:new_ast, "some text")
+
+    refute eval_heex("""
+           <div :type={MyComponent}>Test</div>
+           <span>Another</span>
+           """).root
+  end
+
+  defp eval_heex(source) do
+    require Phoenix.Component
+
+    EEx.compile_string(source,
+      engine: Phoenix.LiveView.TagEngine,
+      line: 1,
+      file: __ENV__.file,
+      trim: true,
+      caller: __ENV__,
+      source: source,
+      tag_handler: Phoenix.LiveView.HTMLEngine
+    )
+    |> Code.eval_quoted(assigns: %{})
+    |> elem(0)
   end
 end