Fix custom element check: require keyword arg to disambiguate from variables

Hyphenated names like app-url are variables, not custom elements.
Only treat as custom element when first arg is a Keyword (tag call pattern).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

shared/static/scripts/sx.js

@@ -1194,7 +1194,7 @@
     var h = v[0];
     if (!isSym(h)) return false;
     var n = h.name;
-    return !!(HTML_TAGS[n] || SVG_TAGS[n] || n === "<>" || n === "raw!" || n.charAt(0) === "~" || n.indexOf("html:") === 0 || n.indexOf("-") > 0);
+    return !!(HTML_TAGS[n] || SVG_TAGS[n] || n === "<>" || n === "raw!" || n.charAt(0) === "~" || n.indexOf("html:") === 0 || (n.indexOf("-") > 0 && v.length > 1 && isKw(v[1])));
   }
 
   function renderComponentDOM(comp, args, env) {
@@ -1317,8 +1317,8 @@
         return warn;
       }
 
-      // Custom element (hyphenated name) → render as element
-      if (name.indexOf("-") > 0) return renderElement(name, expr.slice(1), env, ns);
+      // Custom element (hyphenated name with keyword attrs) → render as element
+      if (name.indexOf("-") > 0 && expr.length > 1 && isKw(expr[1])) return renderElement(name, expr.slice(1), env, ns);
 
       // SVG/MathML namespace auto-detection: inside (svg ...) or (math ...),
       // unknown tags are created with the inherited namespace

shared/sx/async_eval.py

@@ -672,8 +672,8 @@ async def _arender_list(expr: list, env: dict[str, Any], ctx: RequestContext) ->
             if isinstance(val, Component):
                 return await _arender_component(val, expr[1:], env, ctx)
 
-        # Custom element (hyphenated name) → render as tag
-        if "-" in name:
+        # Custom element (hyphenated name with keyword attrs) → tag
+        if "-" in name and len(expr) > 1 and isinstance(expr[1], Keyword):
             return await _arender_element(name, expr[1:], env, ctx)
 
         # SVG/MathML context → unknown names are child elements
@@ -1116,8 +1116,8 @@ async def _aser(expr: Any, env: dict[str, Any], ctx: RequestContext) -> Any:
                 expanded = _expand_macro(val, expr[1:], env)
                 return await _aser(expanded, env, ctx)
 
-        # Custom element (hyphenated name) → serialize as tag
-        if "-" in name:
+        # Custom element (hyphenated name with keyword attrs) → serialize as tag
+        if "-" in name and len(expr) > 1 and isinstance(expr[1], Keyword):
             return await _aser_call(name, expr[1:], env, ctx)
 
         # SVG/MathML context → unknown names are child elements

shared/sx/html.py

@@ -468,8 +468,8 @@ def _render_list(expr: list, env: dict[str, Any]) -> str:
                 return _render_component(val, expr[1:], env)
             # Fall through to evaluation
 
-        # --- Custom element (hyphenated name) → render as tag ------------
-        if "-" in name:
+        # --- Custom element (hyphenated name with keyword attrs) → tag ----
+        if "-" in name and len(expr) > 1 and isinstance(expr[1], Keyword):
             return _render_element(name, expr[1:], env)
 
         # --- SVG/MathML context → unknown names are child elements --------