HTMLRewriter crashes if calling before() without arguments

[mGranTY]

How can we reproduce the crash?

this crashes

const a = await fetch("https://loja.navesa.com.br/lateral-interna-do-paralama-dianteiro-esquerdo-para-renault-sandero-2014-ate-2023-cod-638313232r?_pid=xsbbc")
const rewriter = new HTMLRewriter().on("script", {
    element(a) {
    console.log(a.before())
    },
});
rewriter.transform(a)

this does not

const a = await fetch("https://loja.navesa.com.br/lateral-interna-do-paralama-dianteiro-esquerdo-para-renault-sandero-2014-ate-2023-cod-638313232r?_pid=xsbbc")
const rewriter = new HTMLRewriter().on("script", {
    element(a) {
    console.log(a.before("b"))
    },
});
rewriter.transform(a)

Relevant log output

Stack Trace (bun.report)

Bun v1.2.19 (aad3abe) on linux x86_64 [RunCommand]

panic: unreachable

• JSGlobalObject.zig:596: bun.js.event_loop.tick
• event_loop.zig:403: bun.js.jsc.OpaqueWrap.callback
• bindings.cpp:5326: JSC__VM__holdAPILock
• VM.zig:41: bun_js.Run.boot
• run_command.zig:1246: cli.run_command.RunCommand._bootAndHandleError
• run_command.zig:0: cli.run_command.RunCommand.exec
• cli.zig:861: cli.Command.start
• cli.zig:46: cli.Cli.start
• main.zig:66: main

Features: transpiler_cache, tsconfig, dotenv, fetch, html_rewriter, http_server, jsc

[linear]

ENG-19961 HTMLRewriter crashes if calling before() without arguments

[github-actions]

Thank you for reporting this crash.

For Bun's internal tracking, this issue is BUN-RXY.

[pfgithub]

Minimal reproduction:

// min.html
<script></script>

// c.js
const rewriter = new HTMLRewriter().on("script", {
    element(a) {
        throw new Error("abc");
    },
});
rewriter.transform(new Response(Bun.file("min.html"))); 

Debug build stacktrace:

ASSERTION FAILED: Unexpected exception observed on thread Thread:0x60d000000040 at:
    1   0x104661c30 JSC::ExceptionScope::releaseAssertNoException()
    2   0x104b30cf0 CatchScope__assertNoException
    3   0x11249d6b4 bun.js.bindings.CatchScope.CatchScope.assertionFailure
    4   0x107bb24c8 bun.js.event_loop.DeferredTaskQueue.run
    5   0x1075b5010 bun.js.event_loop.drainMicrotasksWithGlobal
    6   0x107ec1b88 bun.js.event_loop.Task.tickQueueWithCount
    7   0x1078ab354 bun.js.event_loop.tickWithCount
    8   0x107366a98 bun.js.event_loop.tick
    9   0x107ad8338 bun.js.VirtualMachine.tick
    10  0x10751d0fc bun.js.Run.start
    11  0x106e17118 bun.js.jsc.OpaqueWrap__anon_36648__struct_251007.callback
    12  0x10467db98 JSC__VM__holdAPILock
    13  0x10678b93c bun.js.bindings.VM.VM.holdAPILock
    14  0x106d542a0 bun.js.Run.boot
    15  0x106d5b0fc cli.run_command.RunCommand._bootAndHandleError
    16  0x106d5a478 cli.run_command.RunCommand.maybeOpenWithBunJS
    17  0x106d55120 cli.run_command.RunCommand.exec
    18  0x106d770e0 cli.Command.start
    19  0x10669dd18 cli.Cli.start
    20  0x10669a01c main.main
    21  0x106699de8 main
    22  0x19e8cab98 start
The exception was thrown from thread Thread:0x60d000000040 at:
    1   0x110a82128 JSC::VM::throwException(JSC::JSGlobalObject*, JSC::Exception*)
    2   0x110a53e58 JSC::ThrowScope::throwException(JSC::JSGlobalObject*, JSC::Exception*)
    3   0x10467f850 JSC__VM__throwError
    4   0x1075ace10 bun.js.bindings.VM.VM.throwError
    5   0x106edbe24 bun.js.bindings.JSGlobalObject.JSGlobalObject.throwValue
    6   0x10bf1ccd8 bun.js.bindings.JSGlobalObject.JSGlobalObject.throwInvalidArguments__anon_1897874
    7   0x10cd854a0 bun.js.jsc.host_fn.wrapInstanceMethod__struct_2315997.method
    8   0x10cd84f5c ElementPrototype__before
    9   0x1061b3138 WebCore::ElementPrototype__beforeCallback(JSC::JSGlobalObject*, JSC::CallFrame*)
    10  0x30001003c 9   ???                                 0x000000030001003c 0x0 + 12884967484
    11  0x11282f25c op_call_return_location
    12  0x112805b58 llint_call_javascript
    13  0x10f840ff0 JSC::Interpreter::executeCallImpl(JSC::VM&, JSC::JSObject*, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&)
    14  0x10f8418f4 JSC::Interpreter::executeCall(JSC::JSObject*, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&)
    15  0x10fef0108 JSC::call(JSC::JSGlobalObject*, JSC::JSValue, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&)
    16  0x10fef085c JSC::profiledCall(JSC::JSGlobalObject*, JSC::ProfilingReason, JSC::JSValue, JSC::CallData const&, JSC::JSValue, JSC::ArgList const&)
    17  0x10464d840 Bun__JSValue__call
    18  0x10826b088 bun.js.jsc.host_fn.fromJSHostCall__anon_729966
    19  0x107aae358 bun.js.bindings.JSValue.JSValue.call
    20  0x10cebd9e0 bun.js.api.html_rewriter.HandlerCallback__struct_2339270.callback
    21  0x10cebd6a8 bun.js.api.html_rewriter.ElementHandler.onElement
    22  0x10cec6df8 deps.lol-html.DirectiveHandler__anon_2339319__struct_2339639.callback
    23  0x111cb4e18 lolhtml::rewriter_builder::ExternElementContentHandlers::as_safe_element_content_handlers::_$u7b$$u7b$closure$u7d$$u7d$::hbfadaaa0d1c4e32a
    24  0x111cbc32c lol_html::rewriter::handlers_dispatcher::ContentHandlersDispatcher$LT$H$GT$::handle_start_tag::habf5746aadcbc068
    25  0x111ca8b74 lol_html::transform_stream::dispatcher::Dispatcher$LT$C$C$O$GT$::try_produce_token_from_lexeme::hfeb17fb5e1b0e270
    26  0x111ca8268 _$LT$lol_html..transform_stream..dispatcher..Dispatcher$LT$C$C$O$GT$$u20$as$u20$lol_html..parser..lexer..LexemeSink$GT$::handle_tag::h6b8e82b6293ce7ae
    27  0x111cbad08 lol_html::parser::lexer::actions::_$LT$impl$u20$lol_html..parser..state_machine..StateMachineActions$u20$for$u20$lol_html..parser..lexer..Lexer$LT$S$GT$$GT$::emit_tag::ha424ea23e0f07ee1
    28  0x111cb65f8 lol_html::parser::state_machine::StateMachine::tag_name_state::hca276f57b1057641
    29  0x111cb737c lol_html::parser::state_machine::StateMachine::continue_from_bookmark::ha97b177dbb276aa1
    30  0x111cc1238 lol_html::parser::Parser$LT$S$GT$::parse::hef3c8f45cdf9e8b9
    31  0x111caee7c lol_html::transform_stream::TransformStream$LT$C$C$O$GT$::write::hff5f6ab1da5e0535
    32  0x111cbc9d4 lol_html_rewriter_write
    33  0x107671b98 deps.lol-html.HTMLRewriter.write
    34  0x10ced69d8 bun.js.api.html_rewriter.HTMLRewriter.BufferOutputSink.runOutputSink
    35  0x10cecc290 bun.js.api.html_rewriter.HTMLRewriter.BufferOutputSink.onFinishedBuffering
    36  0x10cee3958 bun.js.webcore.Body.ValueBufferer.onStreamPipe
    37  0x10ced9830 bun.js.webcore.Pipe.Wrap(bun.js.webcore.Body.ValueBufferer,(function 'onStreamPipe')).pipe
    38  0x109512748 bun.js.webcore.ByteStream.onData
    39  0x108f71100 bun.js.webcore.fetch.FetchTasklet.onBodyReceived
    40  0x1087c1dec bun.js.webcore.fetch.FetchTasklet.onProgressUpdate
    41  0x107ec4e00 bun.js.event_loop.Task.tickQueueWithCount
    42  0x1078ab354 bun.js.event_loop.tickWithCount
    43  0x107366a98 bun.js.event_loop.tick
    44  0x107ad8338 bun.js.VirtualMachine.tick
    45  0x10751d0fc bun.js.Run.start
    46  0x106e17118 bun.js.jsc.OpaqueWrap__anon_36648__struct_251007.callback
    47  0x10467db98 JSC__VM__holdAPILock
    48  0x10678b93c bun.js.bindings.VM.VM.holdAPILock
    49  0x106d542a0 bun.js.Run.boot
    50  0x106d5b0fc cli.run_command.RunCommand._bootAndHandleError
    51  0x106d5a478 cli.run_command.RunCommand.maybeOpenWithBunJS
    52  0x106d55120 cli.run_command.RunCommand.exec
    53  0x106d770e0 cli.Command.start
    54  0x10669dd18 cli.Cli.start
    55  0x10669a01c main.main
    56  0x106699de8 main
    57  0x19e8cab98 start
Error Exception: Missing argument

!exception()
cache/webkit-75f6499360f42d58/include/JavaScriptCore/ExceptionScope.h(62) : void JSC::ExceptionScope::releaseAssertNoException()
1   0x104661c90 JSC::ExceptionScope::releaseAssertNoException()
2   0x104b30cf0 CatchScope__assertNoException
3   0x11249d6b4 bun.js.bindings.CatchScope.CatchScope.assertionFailure
4   0x107bb24c8 bun.js.event_loop.DeferredTaskQueue.run
5   0x1075b5010 bun.js.event_loop.drainMicrotasksWithGlobal
6   0x107ec1b88 bun.js.event_loop.Task.tickQueueWithCount
7   0x1078ab354 bun.js.event_loop.tickWithCount
8   0x107366a98 bun.js.event_loop.tick
9   0x107ad8338 bun.js.VirtualMachine.tick
10  0x10751d0fc bun.js.Run.start
11  0x106e17118 bun.js.jsc.OpaqueWrap__anon_36648__struct_251007.callback
12  0x10467db98 JSC__VM__holdAPILock
13  0x10678b93c bun.js.bindings.VM.VM.holdAPILock
14  0x106d542a0 bun.js.Run.boot
15  0x106d5b0fc cli.run_command.RunCommand._bootAndHandleError
16  0x106d5a478 cli.run_command.RunCommand.maybeOpenWithBunJS
17  0x106d55120 cli.run_command.RunCommand.exec
18  0x106d770e0 cli.Command.start
19  0x10669dd18 cli.Cli.start
20  0x10669a01c main.main
21  0x106699de8 main
22  0x19e8cab98 start

It's an exception handling bug - exceptions are not being propagated correctly in the element handler.