Windows: Starting headless mode fails to create WR surfman (DeviceOpenFailed)

[PeterZhizhin]

Servo fails to create a headless window with the following error:

PS C:\Users\peter\Documents\Projects\servo> ./mach run --dev --headless https://google.com
Failed to create WR surfman: DeviceOpenFailed (thread main, at ports\glutin\headless_window.rs:42)
   0: backtrace::backtrace::trace_unsynchronized<closure-1>
             at C:\Users\peter\.cargo\registry\src\github.com-1ecc6299db9ec823\backtrace-0.3.46\src\backtrace\mod.rs:66
   1: servo::backtrace::{{impl}}::fmt
             at C:\Users\peter\Documents\Projects\servo\ports\glutin\backtrace.rs:49
   2: core::fmt::write
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libcore\fmt\mod.rs:1069
   3: std::io::Write::write_fmt<std::io::stdio::StdoutLock>
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\src\libstd\io\mod.rs:1504
   4: servo::backtrace::print
             at C:\Users\peter\Documents\Projects\servo\ports\glutin\backtrace.rs:17
   5: servo::main::{{closure}}
             at C:\Users\peter\Documents\Projects\servo\ports\glutin\main2.rs:150
   6: std::panicking::rust_panic_with_hook
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\panicking.rs:515
   7: std::panicking::begin_panic_handler
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\panicking.rs:419
   8: core::panicking::panic_fmt
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libcore\panicking.rs:111
   9: core::option::expect_none_failed
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libcore\option.rs:1268
  10: core::result::Result<webrender_surfman::WebrenderSurfman, surfman::error::Error>::expect<webrender_surfman::WebrenderSurfman,surfman::error::Error>
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\src\libcore\result.rs:963
  11: servo::headless_window::Window::new
             at C:\Users\peter\Documents\Projects\servo\ports\glutin\headless_window.rs:42
  12: servo::app::App::run
             at C:\Users\peter\Documents\Projects\servo\ports\glutin\app.rs:47
  13: servo::main
             at C:\Users\peter\Documents\Projects\servo\ports\glutin\main2.rs:178
  14: std::rt::lang_start::{{closure}}<()>
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\src\libstd\rt.rs:67
  15: std::rt::lang_start_internal::{{closure}}
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\rt.rs:52
  16: std::panicking::try::do_call
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\panicking.rs:331
  17: std::panicking::try
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\panicking.rs:274
  18: std::panic::catch_unwind
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\panic.rs:394
  19: std::rt::lang_start_internal
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\/src\libstd\rt.rs:51
  20: std::rt::lang_start<()>
             at /rustc/42abbd8878d3b67238f3611b0587c704ba94f39c\src\libstd\rt.rs:67
  21: main
  22: invoke_main
             at d:\agent\_work\4\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:78
  23: __scrt_common_main_seh
             at d:\agent\_work\4\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288
  24: BaseThreadInitThunk
  25: RtlUserThreadStart
Servo exited with return value 101

The error leads to this line (as found by @jdm): https://github.com/servo/surfman/blob/ae14cc9afd140bc73e89f3fe8c080f729f09ccd2/surfman/src/platform/windows/angle/device.rs#L162

Unfortunately, actual error code is not returned from the function to the caller, so we don't know more for now.

[jdm]

It might be informative to somehow report the actual failure code from https://github.com/pcwalton/surfman/blob/ae14cc9afd140bc73e89f3fe8c080f729f09ccd2/surfman/src/platform/windows/angle/device.rs#L161-L163 and https://github.com/pcwalton/surfman/blob/ae14cc9afd140bc73e89f3fe8c080f729f09ccd2/surfman/src/platform/windows/wgl/device.rs#L140-L142.

[jdm]

Oh, I know - this is the first time we've tried to actually run surfman headlessly on Windows. We're breaking new ground!

[jdm]

It might be worth adding sm-angle-default to

servo/ports/glutin/Cargo.toml

Line 63 in a478aaf

surfman = { version = "0.2", features = ["sm-winit", "sm-x11"] }

and seeing if that improves the situation.