net.html: unmatched closing tag breaks dom parsing #26619
Description
Describe the bug
When parsing invalid HTML with an extra closing tag and no matching opening tag (for example, </a>), the open-tag stack context gets corrupted.
Reproduction Steps
Run:
import net.html
fn main() {
content := '<!doctype html>
<html>
<body>
<div>
<a href="#">x</a></a>
</div>
<article class="news-post">hello</article>
</body>
</html>'
mut doc := html.parse(content)
// this works because it uses the global index, not the local stack that gets corrupted
by_attr := doc.get_tags_by_attribute_value('class', 'news-post')
println('by_attr: ${by_attr.len}')
// this does not work
by_class := doc.get_tags_by_class_name('news-post')
println('by_class: ${by_class.len}')
}Expected Behavior
In my opinion, invalid unmatched closing tags should be safely ignored.
Current Behavior
Invalid unmatched closing tags break dom parsing.
Possible Solution
Codex suggestion:
In https://github.com/vlang/v/blob/master/vlib/net/html/dom.v#L125, preserve the stack size before the pop loop; if no matching opener is found, restore it and continue (ignore the unmatched closing tag).
if is_close_tag(tag) {
temp_int = stack.peek()
temp_string = tag.name[1..]
+ old_stack_size := stack.size
for !is_null(temp_int) && temp_string != tag_list[temp_int].name
&& !tag_list[temp_int].closed {
dom.print_debug(temp_string + ' >> ' + tag_list[temp_int].name + ' ' +
(temp_string == tag_list[temp_int].name).str())
stack.pop()
temp_int = stack.peek()
}
+
+ if is_null(temp_int) || temp_string != tag_list[temp_int].name {
+ stack.size = old_stack_size
+ continue
+ }
temp_int = stack.peek()
temp_int = if !is_null(temp_int) { stack.pop() } else { root_index }
if is_null(temp_int) {
stack.push(root_index)
}
dom.print_debug('Removed ' + temp_string + ' -- ' + tag_list[temp_int].name)
}
Additional Information/Context
No response
V version
V 0.5.0
Environment details (OS name and version, etc.)
| V full version | V 0.5.0 0d00c76.5e0489f |
|---|---|
| OS | linux, Linux version 6.6.87.2-microsoft-standard-WSL2 (root@439a258ad544) (gcc (GCC) 11.2.0, GNU ld (GNU Binutils) 2.37) #1 SMP PREEMPT_DYNAMIC Thu Jun 5 18:30:46 UTC 2025 (WSL 2) |
| Processor | 6 cpus, 64bit, little endian, AMD Ryzen 5 3500 6-Core Processor |
| Memory | 5.34GB/7.72GB |
| V executable | /root/v/v |
| V last modified time | 2026-02-17 00:36:34 |
| V home dir | OK, value: /root/v |
| VMODULES | OK, value: /root/.vmodules |
| VTMP | OK, value: /tmp/v_0 |
| Current working dir | OK, value: /root/workspace/testando |
| Git version | git version 2.53.0 |
| V git status | weekly.2026.07-76-g5e0489fe-dirty |
| .git/config present | true |
| cc version | cc (GCC) 15.2.1 20260209 |
| gcc version | gcc (GCC) 15.2.1 20260209 |
| clang version | clang version 21.1.8 |
| tcc version | tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux) |
| tcc git status | thirdparty-linux-amd64 696c1d84 |
| emcc version | N/A |
| glibc version | ldd (GNU libc) 2.43 |
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