Layout panic when clicking on link to binary file

[jdm]

eg. firefox.com's download button

stack backtrace:
   1:        0x1037634a0 - sys::backtrace::tracing::imp::write::hd0176e40ebe71d28Vks
   2:        0x1037666a9 - panicking::on_panic::h929e7e75bc4f2c31NXw
   3:        0x103755842 - rt::unwind::begin_unwind_inner::h9d2d49cde66c0c4b0sw
   4:        0x103755eed - rt::unwind::begin_unwind_fmt::h30d162ea92169f156rw
   5:        0x103766107 - rust_begin_unwind
   6:        0x10378b250 - panicking::panic_fmt::ha85fd08dcab4df5d8PE
   7:        0x10378fa70 - str::slice_error_fail::h6c64708b936def9aQ7M
   8:        0x10138e805 - str::traits::str.ops..Index<ops..Range<usize>>::index::h5c712b080eb21315ATM
   9:        0x10138b55e - process_text::h7e728c3015bb297f9Ib
  10:        0x1010d0dad - text::TextRunScanner::scan_for_runs::h68021d2b1d61542efby
  11:        0x1010e2376 - construct::FlowConstructor<'a>::build_flow_for_block_starting_with_fragments::h46af83a2b639423fLKd
  12:        0x1010e5b89 - construct::FlowConstructor<'a>::build_flow_for_block_like::h4254f8a6920a6687mNd
  13:        0x1010e839a - construct::FlowConstructor<'a>::build_flow_for_block::h0515d03cde8d641b8Qd
  14:        0x1010e4944 - construct::FlowConstructor<'a>.PostorderNodeMutTraversal::process::h494f170c6c190dc1Ype
  15:        0x10132055d - traversal::ConstructFlows<'a>.PostorderDomTraversal::process::haa946c6f430b5b960Zy
  16:        0x10132014d - parallel::ParallelPostorderDomTraversal::run_parallel::h1117234973821920439
  17:        0x101320096 - parallel::construct_flows::h6cc091e0b66b0a71b3t
  18:        0x10131eef8 - parallel::RecalcStyleForNode<'a>.ParallelPreorderDomTraversal::run_parallel::h16c6b3f19f38805ae2t
  19:        0x10131ffe2 - parallel::recalc_style::h239c34ec7e22fc3dE2t
  20:        0x10121b3af - workqueue::WorkerThread<QueueData, WorkData>::start::h18037580520219270155
  21:        0x10121ab2f - workqueue::WorkQueue<QueueData, WorkData>::new::closure.53521
  22:        0x10121a9da - task::spawn_named::closure.53514
  23:        0x10121a919 - boxed::F.FnBox<A>::call_box::h15424255898831889789
  24:        0x1011d608b - boxed::Box<FnBox<A, Output $u3d$$u20$R$GT$$u2b$$u20$Send$u20$$u2b$$u20$$u27$a$GT$.FnOnce$LT$A$GT$::call_once::h4324773148212385334
  25:        0x1011d5c6d - thread::Builder::spawn_inner::closure.51699
  26:        0x1011d5c19 - rt::unwind::try::try_fn::h15351741628393356514
  27:        0x1037660b8 - __rust_try
  28:        0x103761dc0 - rt::unwind::try::inner_try::h03cd26bf8e2ee1ceTow
  29:        0x1011d5b83 - rt::unwind::try::h3133819360463872697
  30:        0x1011d59fb - thread::Builder::spawn_inner::closure.51676
  31:        0x1011d62ac - boxed::F.FnBox<A>::call_box::h6128871607861653644
  32:        0x10376546d - sys::thread::Thread::new::thread_start::he62641fb2961f41aBNv
  33:     0x7fff928ae898 - _pthread_body
  34:     0x7fff928ae729 - _pthread_start

[jdm]

thread 'LayoutWorker worker 5/6' panicked at 'index 19431 and/or 19445 in...binary content...do not lie on character boundary', src/libcore/str/mod.rs:1328

[SimonSapin]

I think we should do two things here:

• Not panic when random binary data is parsed as HTML and rendered through layout
• Check the Content-Type header to not even try to render binary resources as HTML. (Eventually, offer a download instead.)

[jdm]

Filed #7706 for part 2.

[eefriedman]

For the panic, I think the issue is here: https://github.com/servo/unicode-bidi/blob/b3813c271853333fe75b553796aec5fe94ecc807/src/lib.rs#L288 . I think i + 1 is supposed to be i + c.len_utf8()? Presumably the issue never came up because real text never uses U+0085 or U+2029.

[SimonSapin]

CC @mbrubeck re unicode-bidi

[mbrubeck]

@eefriedman Good catch. Would you like to file a PR on unicode-bidi to fix that, or shall I?

[eefriedman]

servo/unicode-bidi#17