midi.city panics with "internal error: entered unreachable code: CancelScheduledValues/SetValue should never appear in the timeline"

[jdm]

./mach run -d https://midi.city/ yields:

internal error: entered unreachable code: CancelScheduledValues/SetValue should never appear in the timeline (thread AudioRenderThread, at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/param.rs:318)
stack backtrace:
   0:        0x10c91c394 - __ZN9backtrace9backtrace5trace17hefbd7c3b17ad6e6eE
                        at /Users/jdm/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/backtrace/mod.rs:42
   1:        0x10c91543c - __ZN9backtrace7capture9Backtrace14new_unresolved17hfa7d39a5ef5fb84fE
                        at /Users/jdm/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:88
   2:        0x10c91539e - __ZN9backtrace7capture9Backtrace3new17hb34b0ddcba79179eE
                        at /Users/jdm/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.9/src/capture.rs:63
   3:        0x1069dfb60 - __ZN5servo4main28_$u7b$$u7b$closure$u7d$$u7d$17h7f3fe551d03f80b0E
                        at ports/servo/non_android_main.rs:111
   4:        0x10e6dfe08 - __ZN3std9panicking20rust_panic_with_hook17h14490a1041ee4235E
                        at libstd/panicking.rs:480
   5:        0x10e6df91c - __ZN3std9panicking18continue_panic_fmt17h7beddad0ba45f4eaE
                        at libstd/panicking.rs:390
   6:        0x10e6df870 - __ZN3std9panicking15begin_panic_fmt17h19527e965f98f107E
                        at libstd/panicking.rs:345
   7:        0x109eda4af - __ZN17servo_media_audio5param15AutomationEvent4time17h92c6827fe61d766bE
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/param.rs:318
   8:        0x109ed9ad6 - __ZN17servo_media_audio5param5Param12insert_event17hec97b7bfab456939E
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/param.rs:188
   9:        0x109de99f7 - __ZN17servo_media_audio4node15AudioNodeEngine7message17h731f0e30ee88e1c0E
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/node.rs:126
  10:        0x109de310c - __ZN69_$LT$servo_media_audio..render_thread..AudioRenderThread$LT$S$GT$$GT$10event_loop28_$u7b$$u7b$closure$u7d$$u7d$17hffd1b796b5a66e0cE
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/render_thread.rs:254
  11:        0x109de1922 - __ZN69_$LT$servo_media_audio..render_thread..AudioRenderThread$LT$S$GT$$GT$10event_loop17h7b89e29b77ab2459E
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/render_thread.rs:292
  12:        0x109de5cf1 - __ZN69_$LT$servo_media_audio..render_thread..AudioRenderThread$LT$S$GT$$GT$5start17h400228aff06919a7E
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/render_thread.rs:159
  13:        0x109e035b4 - __ZN58_$LT$servo_media_audio..context..AudioContext$LT$B$GT$$GT$3new28_$u7b$$u7b$closure$u7d$$u7d$17h37525165597cf22fE
                        at /Users/jdm/.cargo/git/checkouts/media-c23a3cd5aa97076a/352072f/audio/src/context.rs:137
  14:        0x109dec864 - __ZN3std10sys_common9backtrace28__rust_begin_short_backtrace17h92a251424c2fd43fE
                        at libstd/sys_common/backtrace.rs:136
  15:        0x109e00e44 - __ZN3std6thread7Builder5spawn28_$u7b$$u7b$closure$u7d$$u7d$28_$u7b$$u7b$closure$u7d$$u7d$17hacf0a3fec65dfd81E
                        at libstd/thread/mod.rs:409
  16:        0x109dec274 - __ZN101_$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$9call_once17he089024d982f6fa8E
                        at libstd/panic.rs:313
  17:        0x109def164 - __ZN3std9panicking3try7do_call17h2228f77087c9f309E
                        at libstd/panicking.rs:310
  18:        0x10e6ec37e - ___rust_maybe_catch_panic
                        at libpanic_unwind/lib.rs:102
  19:        0x109def043 - __ZN3std9panicking3try17h1369a4767145ca2dE
                        at libstd/panicking.rs:289
  20:        0x109deca94 - __ZN3std5panic12catch_unwind17h094a535d777cd760E
                        at libstd/panic.rs:392
  21:        0x109e00c6e - __ZN3std6thread7Builder5spawn28_$u7b$$u7b$closure$u7d$$u7d$17h9d98e6cb80cc20c2E
                        at libstd/thread/mod.rs:408
  22:        0x109e00eb3 - __ZN50_$LT$F$u20$as$u20$alloc..boxed..FnBox$LT$A$GT$$GT$8call_box17h020ffcda8d80c913E
                        at liballoc/boxed.rs:672
  23:        0x10e6c331b - __ZN3std3sys4unix6thread6Thread3new12thread_start17hba53abd905cebc29E
                        at libstd/sys_common/thread.rs:24
  24:     0x7fffae9ec93a - __pthread_body
  25:     0x7fffae9ec886 - __pthread_start

[highfive]

Hi! If you have any questions regarding this issue, feel free to make a comment here, or ask it in the #servo channel in IRC.

If you intend to work on this issue, then add @highfive: assign me to your comment, and I'll assign this to you. 😄

[ferjm]

This should likely be unimplemented instead of unreachable cause we have the DOM and the glue code already in place, so the code is actually reachable.

[jdm]

That will still panic, right?

[ferjm]

Er, right. A warn, println or even no-op then, until #22367 is done.

[okevese]

Hello, I would like to work on this issue, @highfive: assign me

[highfive]

Hey @okevese! Thanks for your interest in working on this issue. It's now assigned to you!

[okevese]

@jdm I get the following error when building servo on Linux Mint 18.3. I ran ./mach bootstrap successfully and I'm using clang 6.0

undefined reference to 'gst_promise_new_with_change_func
...
undefined reference to 'gst_player_config_set_position_update_interval'
...
undefined reference to 'gst_player_media_info_get_number_of_video_streams'
...
undefined reference to 'gst_player_media_info_is_live'

Please can you help pinpoint the problem?

[jdm]

It sounds like you need to update the version of GStreamer that you have installed.

[okevese]

I've done that and still get the same error. I'm currently checking the gstreamer.rs dependencies of servo/media, maybe that's where the problem is.

[flofriday]

#22367 seems to got implemented, since this issue got opened.

However, servo still panics when loading https://midi.city/.
Should this still be converted into a warn or println?

[jdm]

@flofriday Good catch! That code should return the tick value from CancelScheduledValues: https://doc.servo.org/servo_media_audio/param/enum.AutomationEvent.html#variant.CancelScheduledValues

[Axighi]

If this issue is still open, @highfive: assign me

[highfive]

Hey @Axighi! Thanks for your interest in working on this issue. It's now assigned to you!

[dralley]

If this would be a good first issue to tackle, I would like to pick it up (if not, never mind). I've reproduced it on my machine. I'm not sure how I need to set up the environment to build against a local source copy of https://github.com/servo/media though.

[jdm]

https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#overriding-dependencies describes how to make Servo depend on your local clone of the repository.

servo/Cargo.toml

Lines 17 to 26 in 61d2641

	[patch.crates-io]
	# If you need to temporarily test Servo with a local fork of some upstream
	# crate, add that here. Use the form:
	#
	# <crate> = { path = "/path/to/local/checkout" }
	#
	# Or for a git dependency:
	#
	# [patch."https://github.com/servo/<repository>"]
	# <crate> = { path = "/path/to/local/checkout" }

has some documentation to help as well.

[jdm]

And yes, this should be a good first issue to fix!

[dralley]

@jdm With this in my Cargo.toml

[patch."https://github.com/servo/media.git"]
servo-media-audio = { path = "../media/audio"}

I get this

warning: Patch `servo-media-audio v0.1.0 (/home/dalley/Devel/media/audio)` was not used in the crate graph.
Check that the patched package version and available features are compatible
with the dependency requirements. If the patch has a different version from
what is locked in the Cargo.lock file, run `cargo update` to use the new
version. This may also occur with an optional dependency that is not enabled.

[jdm]

What if you run cargo update -p servo-media-audio?

[dralley]

[dalley@localhost servo]$ cargo update -p servo-media-audio
    Updating git repository `https://github.com/servo/media`
    Updating crates.io index
warning: Patch `servo-media-audio v0.1.0 (/home/dalley/Devel/media/audio)` was not used in the crate graph.
Check that the patched package version and available features are compatible
with the dependency requirements. If the patch has a different version from
what is locked in the Cargo.lock file, run `cargo update` to use the new
version. This may also occur with an optional dependency that is not enabled.

[dalley@localhost servo]$ ./mach build --dev
warning: Patch `servo-media-audio v0.1.0 (/home/dalley/Devel/media/audio)` was not used in the crate graph.
Check that the patched package version and available features are compatible
with the dependency requirements. If the patch has a different version from
what is locked in the Cargo.lock file, run `cargo update` to use the new
version. This may also occur with an optional dependency that is not enabled.
    Finished dev [unoptimized + debuginfo] target(s) in 1.05s
Build Completed in 0:00:01

FYI I joined the Moznet IRC #servo channel (nick: dalley) if you want to keep dev env debugging out of the issue discussion.

[jdm]

When I add this to my cargo.toml:

[patch."https://github.com/servo/media"]
servo-media-audio = { path = "../media/audio" }

and run cargo update -p servo-media-audio, I see this output:

godot:master-servo jdm$ cargo update -p servo-media-audio
    Updating git repository `https://github.com/servo/media`
    Updating crates.io index
    Removing servo-media-audio v0.1.0 (https://github.com/servo/media#ecd5a7c6)
      Adding servo-media-audio v0.1.0 (/Users/jdm/src/media/audio)
    Removing servo_media_derive v0.1.0 (https://github.com/servo/media#ecd5a7c6)
      Adding servo_media_derive v0.1.0 (/Users/jdm/src/media/servo-media-derive)

[jdm]

Try removing the .git from the patch name.