hasAttribute is not a function

[KTibow]

Describe the bug

some specific code specifically in sveltekit specifically when built causes a runtime error, likely due to there being no value assigned

this may seem like a silly case but it makes sense when only demonstrating UI components

if this behavior shouldn't be allowed, then svelte should error at compile time

Reproduction

https://github.com/KTibow/hasattributebug

Logs

2.C2l9EObT.js:36 Uncaught (in promise) TypeError: input.hasAttribute is not a function
    at Array.remove_defaults (2.C2l9EObT.js:36:15)
    at run_all (BjTd4EYN.js:18:11)
    at process_idle_tasks (BjTd4EYN.js:787:3)
    at flush_tasks (BjTd4EYN.js:808:5)
    at flush_sync (BjTd4EYN.js:1265:5)
    at new Svelte4Component (app.LvR6wlp0.js:446:7)
    at new <anonymous> (app.LvR6wlp0.js:395:7)
    at initialize (DSRet70y.js:1061:10)
    at _hydrate (DSRet70y.js:2210:3)
    at async Module.start (DSRet70y.js:973:5)

System Info

System:
    OS: Linux 6.12 Fedora Linux 41 (Workstation Edition)
    CPU: (8) x64 Intel(R) Core(TM) i5-1035G4 CPU @ 1.10GHz
    Memory: 7.24 GB / 15.21 GB
    Container: Yes
    Shell: 3.7.0 - /usr/bin/fish
  Binaries:
    Node: 22.12.0 - ~/.local/share/pnpm/node
    npm: 10.9.0 - ~/.local/share/pnpm/npm
    pnpm: 10.2.0 - ~/.local/share/pnpm/pnpm
  npmPackages:
    svelte: ^5.0.0 => 5.19.9

Severity

annoyance

[ranjan-purbey]

This works:

<!-- routes/+page.svelte -->
<input checked />

This fails:

<!-- routes/+page.svelte -->
text <input checked />

and so does this:

<!-- routes/+page.svelte -->
<div></div>
<input checked />

This works again:

<!-- routes/+page.svelte -->
<div></div>
<div>
    <input checked />
</div>

and so does this:

<!-- routes/+page.svelte -->
<div></div>
<input />

Issue occurs in both dev and preview. With JS disabled in the browser, the page loads fine though. Also no issue when running the same code in Svelte REPL or when using svelte template with npm create vite.
Kit versions tested: 2.17.1, 2.5.3
Svelte versions tested: 5.19.9. 5.0.0

Diff of compiler outputs in the two cases

--- just_input.js	2025-02-08 14:30:15.887715835 +0530
+++ input_with_siblings.js	2025-02-08 14:29:58.129556652 +0530
@@ -1,21 +1,23 @@
-import { createHotContext as __vite__createHotContext } from "/@vite/client";import.meta.hot = __vite__createHotContext("/src/routes/+layout.svelte");import "/node_modules/.vite/deps/svelte_internal_disclose-version.js?v=44ac6c46";
+import { createHotContext as __vite__createHotContext } from "/@vite/client";
+import "/node_modules/.vite/deps/svelte_internal_disclose-version.js?v=44ac6c46";
 import "/node_modules/.vite/deps/svelte_internal_flags_legacy.js?v=44ac6c46";
-
+import.meta.hot = __vite__createHotContext("/src/routes/+layout.svelte");
 $.mark_module_start();
 _layout[$.FILENAME] = 'src/routes/+layout.svelte';
 
 import * as $ from "/node_modules/.vite/deps/svelte_internal_client.js?v=44ac6c46";
 
-var root = $.add_locations($.template(`<input checked>`), _layout[$.FILENAME], [[4, 0]]);
+var root = $.add_locations($.template(`<input checked> .`, 1), _layout[$.FILENAME], [[4, 0]]);
 
 function _layout($$anchor, $$props) {
 	$.check_target(new.target);
 	$.push($$props, false, _layout);
 
-	var input = root();
+	var fragment = root();
 
-	$.remove_input_defaults(input);
-	$.append($$anchor, input);
+	$.remove_input_defaults();
+	$.next();
+	$.append($$anchor, fragment);
 	return $.pop({ ...$.legacy_api() });
 }

Here we can see that remove_input_defaults is called without any args in the case where root-level <input> has a sibling node.