Panic instantiating a font

[jdm]

./mach run -w -d --debug https://www.computest.nl/blog/startencrypt-considered-harmful-today/

thread 'FontCacheThread' panicked at 'assertion failed: `(left == right)` (left: `112164`, right: `46628`)', /Users/jdm/src/servo/components/gfx/platform/macos/font.rs:120

(lldb) bt
error: need to add support for DW_TAG_base_type '()' encoded with DW_ATE = 0x7, bit_size = 0
* thread #23: tid = 0x20b7c9, 0x00000001048eda90 servo`rust_panic, name = 'FontCacheThread', stop reason = breakpoint 1.1
  * frame #0: 0x00000001048eda90 servo`rust_panic
    frame #1: 0x00000001048e362d servo`std::panicking::rust_panic_with_hook::h983af77c1a2e581b + 413
    frame #2: 0x00000001048fc6d7 servo`std::panicking::begin_panic::he426e15a3766089a + 103
    frame #3: 0x00000001048e4c29 servo`std::panicking::begin_panic_fmt::hdddb415186c241e7 + 169
    frame #4: 0x0000000102b80ae6 servo`gfx::platform::macos::font::{{impl}}::find_h_kern_subtable(self=0x000000011e7ffc38) + 3046 at <std macros>:8
    frame #5: 0x0000000102b44d12 servo`gfx::platform::macos::font::{{impl}}::new_from_template(_fctx=0x000000011e8007d8, template=Arc<gfx::platform::macos::font_template::FontTemplateData> at 0x000000011e7ffcf8, pt_size=Option<app_units::app_unit::Au> at 0x000000011e7ffce8) + 562 at font.rs:185
    frame #6: 0x0000000102b50581 servo`gfx::font_template::{{impl}}::instantiate(self=0x000000011ec6c000, font_context=0x000000011e8007d8) + 145 at font_template.rs:168
    frame #7: 0x0000000102ac8de6 servo`gfx::font_template::{{impl}}::data_for_descriptor(self=0x000000011ec6c000, fctx=0x000000011e8007d8, requested_desc=0x000000011e800578) + 182 at font_template.rs:123
    frame #8: 0x0000000102ac853b servo`gfx::font_cache_thread::{{impl}}::find_font_for_style(self=0x000000011ec15538, desc=0x000000011e800578, fctx=0x000000011e8007d8) + 331 at font_cache_thread.rs:56
    frame #9: 0x0000000102b2c1d2 servo`gfx::font_cache_thread::{{impl}}::find_font_in_web_family(self=0x000000011e800750, family=0x000000011e800638, desc=0x000000011e800578) + 258 at font_cache_thread.rs:327
    frame #10: 0x0000000102aef38f servo`gfx::font_cache_thread::{{impl}}::find_font_template(self=0x000000011e800750, family=0x000000011e800638, desc=0x000000011e800578) + 63 at font_cache_thread.rs:353
    frame #11: 0x0000000102ad1a15 servo`gfx::font_cache_thread::{{impl}}::run(self=0x000000011e800750) + 309 at font_cache_thread.rs:167
    frame #12: 0x0000000102b35785 servo`gfx::font_cache_thread::{{impl}}::new::{{closure}} + 709 at font_cache_thread.rs:410
    frame #13: 0x0000000102b35478 servo`std::panic::{{impl}}::call_once<(self=AssertUnwindSafe<closure> at 0x000000011e8008d8, _args=<unavailable>),closure> + 168 at panic.rs:251
    frame #14: 0x0000000102b353b6 servo`std::panicking::try::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::hba6876ddabbbc7a6 + 86
    frame #15: 0x0000000102b35d65 servo`std::panicking::try::call<closure>(f=0x000000011e800a98) + 21 at panicking.rs:272
    frame #16: 0x00000001048ff3bc servo`__rust_try + 12
    frame #17: 0x00000001048ff356 servo`__rust_maybe_catch_panic + 38
    frame #18: 0x0000000102b350ae servo`std::panicking::try::_$u7b$$u7b$closure$u7d$$u7d$::hdaa55c6034c35e44 + 158
    frame #19: 0x0000000102b34f90 servo`std::thread::local::{{impl}}::with<core::cell::Cell<usize>,closure,core::result::Result<(self=0x00000001060fa6a0, f=closure at 0x000000011e800b38), Box<Any>>> + 208 at local.rs:211
    frame #20: 0x0000000102b34dc8 servo`std::panicking::try<(f=AssertUnwindSafe<closure> at 0x000000011e800c08),std::panic::AssertUnwindSafe<closure>> + 248 at panicking.rs:235
    frame #21: 0x0000000102b34c82 servo`std::panic::catch_unwind<std::panic::AssertUnwindSafe<closure>,(f=AssertUnwindSafe<closure> at 0x000000011e800ca8)> + 178 at panic.rs:307
    frame #22: 0x0000000102b34ac7 servo`std::thread::Builder::spawn::_$u7b$$u7b$closure$u7d$$u7d$::h8ba1a69ff341fbec + 391
    frame #23: 0x0000000102b36101 servo`alloc::boxed::{{impl}}::call_box<(self=0x000000010ce17dc0, args=<unavailable>),closure> + 97 at boxed.rs:544
    frame #24: 0x00000001048fae39 servo`std::sys::thread::Thread::new::thread_start::h9c883b6d445ece46 + 57
    frame #25: 0x00007fff8fd62899 libsystem_pthread.dylib`_pthread_body + 138
    frame #26: 0x00007fff8fd6272a libsystem_pthread.dylib`_pthread_start + 137
    frame #27: 0x00007fff8fd66fc9 libsystem_pthread.dylib`thread_start + 13

[jdm]

@mbrubeck The assertion here was added as part of the fast path in #11273.