Parser: Introduce VoidElementContentError (#1454)

This pull request updates the parser to introduce a new
`VoidElementContentError` that gets added to a `HTMLElementNode` that
was transformed from a `tag` or `content_tag` call when the tag used is
a void element.

For example:
```erb
<%= content_tag :img, "/image.png" %>
```

Now gets parsed as the following with `action_view_helpers: true`:
```js
@ DocumentNode (location: (1:0)-(1:37))
└── children: (1 item)
    └── @ HTMLElementNode (location: (1:0)-(1:37))
        ├── errors: (1 error)
        │   └── @ VoidElementContentError (location: (1:0)-(1:37))
        │       ├── message: "Void element `img` cannot have content. `img` does not accept positional arguments."
        │       └── tag_name: "img" (location: (1:4)-(1:15))
        │
        ├── open_tag:
        │   └── @ ERBOpenTagNode (location: (1:0)-(1:37))
        │       ├── tag_opening: "<%=" (location: (1:0)-(1:3))
        │       ├── content: " content_tag :img, "/image.png" " (location: (1:3)-(1:35))
        │       ├── tag_closing: "%>" (location: (1:35)-(1:37))
        │       ├── tag_name: "img" (location: (1:4)-(1:15))
        │       └── children: []
        │
        ├── tag_name: "img" (location: (1:4)-(1:15))
        ├── body: (1 item)
        │   └── @ HTMLTextNode (location: (1:0)-(1:37))
        │       └── content: "/image.png"
        │
        ├── close_tag: ∅
        ├── is_void: true
        └── element_source: "ActionView::Helpers::TagHelper#content_tag"
```

It also catches:
```erb
<%= tag.img "/image.png" %>
```

```js
@ DocumentNode (location: (1:0)-(1:27))
└── children: (1 item)
    └── @ HTMLElementNode (location: (1:0)-(1:27))
        ├── errors: (1 error)
        │   └── @ VoidElementContentError (location: (1:0)-(1:27))
        │       ├── message: "Void element `img` cannot have content. `img` does not accept positional arguments."
        │       └── tag_name: "img" (location: (1:8)-(1:11))
        │
        ├── open_tag:
        │   └── @ ERBOpenTagNode (location: (1:0)-(1:27))
        │       ├── tag_opening: "<%=" (location: (1:0)-(1:3))
        │       ├── content: " tag.img "/image.png" " (location: (1:3)-(1:25))
        │       ├── tag_closing: "%>" (location: (1:25)-(1:27))
        │       ├── tag_name: "img" (location: (1:8)-(1:11))
        │       └── children: []
        │
        ├── tag_name: "img" (location: (1:8)-(1:11))
        ├── body: (1 item)
        │   └── @ HTMLTextNode (location: (1:0)-(1:27))
        │       └── content: "/image.png"
        │
        ├── close_tag: ∅
        ├── is_void: true
        └── element_source: "ActionView::Helpers::TagHelper#tag"
```

Author: marcoroth

config.yml

@@ -458,6 +458,17 @@ errors:
 
       fields: []
 
+    - name: VoidElementContentError
+      message:
+        template: "Void element `%s` cannot have content. `%s` does not accept positional arguments."
+        arguments:
+          - tag_name->value
+          - tag_name->value
+
+      fields:
+        - name: tag_name
+          type: token
+
     - name: DotNotationCasingError
       message:
         template: "Dot-notation component tags require the first segment to start with an uppercase letter. `%s` does not start with an uppercase letter."

sig/herb/errors.rbs

@@ -8,6 +8,7 @@
 #include "../../include/lib/hb_allocator.h"
 #include "../../include/lib/hb_array.h"
 #include "../../include/lib/hb_string.h"
+#include "../../include/lib/string.h"
 #include "../../include/location/position.h"
 #include "../../include/parser/parser_helpers.h"
 #include "../../include/util/html_util.h"
@@ -431,10 +432,22 @@ static AST_NODE_T* transform_tag_helper_with_attributes(
   );
 
   hb_array_T* body = hb_array_init(1, allocator);
-  bool is_void = tag_name && ((strcmp(handler->name, "tag") == 0) || (strcmp(handler->name, "image_tag") == 0))
-              && is_void_element(hb_string_from_c_string(tag_name));
+  hb_array_T* element_errors = hb_array_init(0, allocator);
+  bool is_void = tag_name && is_void_element(hb_string_from_c_string(tag_name))
+              && (string_equals(handler->name, "tag") || string_equals(handler->name, "content_tag")
+                  || string_equals(handler->name, "image_tag"));
 
   if (helper_content) {
+    if (is_void) {
+      append_void_element_content_error(
+        tag_name_token,
+        erb_node->base.location.start,
+        erb_node->base.location.end,
+        allocator,
+        element_errors
+      );
+    }
+
     append_body_content_node(
       body,
       helper_content,
@@ -468,7 +481,7 @@ static AST_NODE_T* transform_tag_helper_with_attributes(
     handler->source,
     erb_node->base.location.start,
     erb_node->base.location.end,
-    hb_array_init(0, allocator),
+    element_errors,
     allocator
   );
 

src/analyze/action_view/tag_helpers.c

@@ -257,5 +257,17 @@ class ContentTagTest < Minitest::Spec
         <%= content_tag(:script, "alert('Hello')", nonce: false) %>
       HTML
     end
+
+    test "content_tag with void element img and content argument reports error" do
+      assert_parsed_snapshot(<<~HTML, action_view_helpers: true)
+        <%= content_tag :img, "hello" %>
+      HTML
+    end
+
+    test "content_tag with void element br and content argument reports error" do
+      assert_parsed_snapshot(<<~HTML, action_view_helpers: true)
+        <%= content_tag :br, "hello" %>
+      HTML
+    end
   end
 end

test/analyze/action_view/tag_helper/content_tag_test.rb

@@ -346,5 +346,17 @@ class TagTest < Minitest::Spec
         <%= tag.script(nonce: false) { "alert('Hello')".html_safe } %>
       HTML
     end
+
+    test "tag.img with content argument reports void element content error" do
+      assert_parsed_snapshot(<<~HTML, action_view_helpers: true)
+        <%= tag.img "/image.png" %>
+      HTML
+    end
+
+    test "tag.img with content argument and data attributes reports void element content error" do
+      assert_parsed_snapshot(<<~HTML, action_view_helpers: true)
+        <%= tag.img "/image.png", data: { controller: "image" } %>
+      HTML
+    end
   end
 end