fix(parse/html): handle unclosed elements more gracefully

Author: dyc3

crates/biome_html_factory/src/generated/node_factory.rs

@@ -28,7 +28,6 @@ impl FormatNodeRule<HtmlElement> for FormatHtmlElement {
             closing_element,
         } = node.as_fields();
 
-        let closing_element = closing_element?;
         let opening_element = opening_element?;
         let tag_name = opening_element.name()?;
         let tag_name = tag_name
@@ -62,9 +61,13 @@ impl FormatNodeRule<HtmlElement> for FormatHtmlElement {
             .last_token()
             .is_some_and(|tok| tok.has_trailing_whitespace())
             || closing_element
-                .l_angle_token()
-                .ok()
-                .is_some_and(|tok| tok.has_leading_whitespace_or_newline());
+                .as_ref()
+                .map(|e| {
+                    e.l_angle_token()
+                        .ok()
+                        .is_some_and(|tok| tok.has_leading_whitespace_or_newline())
+                })
+                .unwrap_or_default();
 
         // "Borrowing" in this context refers to tokens in nodes that would normally be
         // formatted by that node's formatter, but are instead formatted by a sibling
@@ -98,7 +101,7 @@ impl FormatNodeRule<HtmlElement> for FormatHtmlElement {
             None
         };
         let borrowed_closing_tag = if should_borrow_closing_tag {
-            Some(closing_element.clone())
+            closing_element.clone()
         } else {
             None
         };
@@ -147,13 +150,17 @@ impl FormatNodeRule<HtmlElement> for FormatHtmlElement {
                 }
             }
         }
-        FormatNodeRule::fmt(
-            &FormatHtmlClosingElement::default().with_options(FormatHtmlClosingElementOptions {
-                tag_borrowed: should_borrow_closing_tag,
-            }),
-            &closing_element,
-            f,
-        )?;
+        if let Some(closing_element) = closing_element {
+            FormatNodeRule::fmt(
+                &FormatHtmlClosingElement::default().with_options(
+                    FormatHtmlClosingElementOptions {
+                        tag_borrowed: should_borrow_closing_tag,
+                    },
+                ),
+                &closing_element,
+                f,
+            )?;
+        }
 
         Ok(())
     }

crates/biome_html_formatter/src/html/auxiliary/element.rs

@@ -84,7 +84,7 @@ HtmlSelfClosingElement =
 HtmlElement =
 	opening_element: HtmlOpeningElement
 	children: HtmlElementList
-	closing_element: HtmlClosingElement
+	closing_element: HtmlClosingElement?
 
 
 // <a href="">