User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:67.0) Gecko/20100101 Firefox/67.0

Steps to reproduce:

1. Enabled the new prefers-color-scheme via ui.systemUsesDarkTheme
2. Tested that it worked as expected with a normal HTML + CSS document (it did).
3. Loaded a plain-text HTTP response. Example document: https://www.rfc-editor.org/rfc/rfc2549.txt

Actual results:

It displayed in light mode example.

Expected results:

It should have displayed in dark mode, since I have prefers-color-scheme set to dark.

I know that CSS doesn't affect plain-text documents, but it makes sense to me that if the user has indicated their preference for a dark theme via prefers-color-scheme, it would stand to reason that they'd want plain-text documents to follow this trend.

https://searchfox.org/mozilla-central/source/layout/style/res/plaintext.css is the stylesheet to modify for this, but this is web-observable so it may be a source of compat bugs.

I think if we are okay with my approach to fixing bug 1408122, that approach could be extended to not only apply to about:blank, but also top-level plain-text documents.

Actually that wouldn't work, because the text would still be black.

I will be happy to append some color scheme rules to plaintext.css if anyone can send me some brief instructions on how to submit my patch. Perhaps to avoid breaking webpages a new stylesheet and some scripting is required, to only register the stylesheet on pages with certain directives, a lack of linked css or inline styles, etc.

(In reply to shmediaproductions from comment #7)

I will be happy to append some color scheme rules to plaintext.css if anyone can send me some brief instructions on how to submit my patch. Perhaps to avoid breaking webpages a new stylesheet and some scripting is required, to only register the stylesheet on pages with certain directives, a lack of linked css or inline styles, etc.

The right thing to do is to only load these styles iff the page is a top level document with no opener. We could either expose it as a media query or conditionally load it in C++ the same way we decide to load plaintext.css.

Is there any way we can use UI style variables for these documents, like how the browser handles its own dark theme rules?
:root:-moz-lwtheme[lwt-toolbar-field-focus-brighttext] {
--urlbar-popup-url-color: hsl(207.2, 100%, 72.7%);
--urlbar-popup-action-color: hsl(109.9, 90.9%, 47.3%);
--urlbarView-button-background: hsla(240, 9.1%, 97.8%, 0.24);
--urlbarView-button-background-hover: hsla(240, 9.1%, 97.8%, 0.15);
--urlbarView-button-background-active: hsla(240, 9.1%, 97.8%, 0.2);
}

If so then we could just change plaintext.css to use global variables, and modulate the variables by prefs or theme

No, using custom properties is a no go because the page can observe them from getComputedStyle. We could use the preprocessor though.

Seems like we could do two things, one simpler and one more complex:

• add a plain-text-document thing to moz-document. This allows detecting plaintext from user stylesheets.
• Add a non-web-observable thing (to moz-document as well probably?). That allows us to fix plaintext.css to for dark mode without it being observable.

I'll try to come up with something, or some instructions.

We'll use it to use @-moz-document from plaintext.css.

Depends on D101516

We add two @-moz-document functions: plain-text-document(), matching the
obvious, and unobservable-document(), which matches a top-level document with
no opener. This is the equivalent check we do for automatic darkening of
about:blank here:

https://searchfox.org/mozilla-central/rev/014fe72eaba26dcf6082fb9bbaf208f97a38594e/layout/base/PresShell.cpp#5282

The former we don't need to use, but it's nice to let user stylesheets target
plaintext documents properly (rather than relying on extensions or what not).

Note that these are not content-observable.

Add two tests: One showing that we produce different rendering when on dark
mode, and one showing that we produce the same one from an iframe, regardless
of dark mode.

Depends on D101517

Backed out 4 changesets (Bug 1551040) for causing mochitest failures.

Backout link: https://hg.mozilla.org/integration/autoland/rev/163a91f9fe87951f7e0f9d5462b68e40e9e1fb67

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&resultStatus=testfailed%2Cbusted%2Cexception&tochange=33f255475ce3ca90d17d68f282d12b636bceab85&fromchange=0eb470b7f12e7ada34473734ba66c16d58de783e&searchStr=mochites&selectedTaskRun=NSNn5ie_QiCbPLD7xK-QNg.0

Failure logs:

• plain: https://treeherder.mozilla.org/logviewer?job_id=326890581&repo=autoland&lineNumber=2253
• bc: https://treeherder.mozilla.org/logviewer?job_id=326889101&repo=autoland&lineNumber=3244

Backed out 3 changesets (bug 1551040) for stylesheets related bustage.

Push with failure: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&selectedTaskRun=IF-xGAMZTt2Jc9qxCdUTXw.0&fromchange=6083cdb61f421976f3fb97357b028f2d71d58924&searchStr=build&tochange=72d4c2b741f3cd7ce17c2d42f1c56c278c03854f

Backout link: https://hg.mozilla.org/integration/autoland/rev/72d4c2b741f3cd7ce17c2d42f1c56c278c03854f

Failure log: https://treeherder.mozilla.org/logviewer?job_id=326911384&repo=autoland&lineNumber=44435

...
[task 2021-01-16T18:45:00.969Z] 18:45:00     INFO -  [style 0.0.1] cargo:rerun-if-changed=/builds/worker/workspace/obj-build/dist/include/mozilla/dom/DocumentFragment.h
[task 2021-01-16T18:45:00.973Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=style CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/servo/components/style CARGO_PKG_AUTHORS='The Servo Project Developers' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE=MPL-2.0 CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=style CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.0.1 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=0 CARGO_PKG_VERSION_PATCH=1 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' OUT_DIR=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/style-2208e51312932126/out /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name style --edition=2018 servo/components/style/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --cfg 'feature="bindgen"' --cfg 'feature="gecko"' --cfg 'feature="gecko_debug"' --cfg 'feature="gecko_profiler"' --cfg 'feature="gecko_refcount_logging"' --cfg 'feature="nsstring"' --cfg 'feature="regex"' --cfg 'feature="serde"' --cfg 'feature="toml"' -C metadata=6d1c2008b56c2e7e -C extra-filename=-6d1c2008b56c2e7e --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern app_units=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libapp_units-45bc3bbb1d0cfc77.rmeta --extern arrayvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libarrayvec-b278ad1a4e8afa7e.rmeta --extern atomic_refcell=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libatomic_refcell-9e29407210814513.rmeta --extern bitflags=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libbitflags-3c52993b6e9c8f85.rmeta --extern byteorder=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libbyteorder-a709cab588b88216.rmeta --extern cssparser=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libcssparser-a48b826af352969a.rmeta --extern derive_more=/builds/worker/workspace/obj-build/debug/deps/libderive_more-58657d1461fa585f.so --extern euclid=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libeuclid-8e6df5e35d8376ab.rmeta --extern fallible=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libfallible-68149472bb410fe7.rmeta --extern fxhash=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libfxhash-26cd111602687ad5.rmeta --extern hashbrown=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libhashbrown-7ba21a05e60fdcb4.rmeta --extern hashglobe=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libhashglobe-7fa107c69cd44197.rmeta --extern indexmap=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libindexmap-f16b53fb18c2dc78.rmeta --extern itertools=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libitertools-bbbad24f578d65ff.rmeta --extern itoa=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libitoa-cbd5dfc4905fbd8f.rmeta --extern lazy_static=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblazy_static-06a33473784416a3.rmeta --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern malloc_size_of=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libmalloc_size_of-c525249a719ab41f.rmeta --extern malloc_size_of_derive=/builds/worker/workspace/obj-build/debug/deps/libmalloc_size_of_derive-6a504c736f6af2f5.so --extern matches=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libmatches-910515041b1a4296.rmeta --extern debug_unreachable=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libdebug_unreachable-6a799d2727fc4cea.rmeta --extern nsstring=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnsstring-1566dcdc2b7a5129.rmeta --extern num_derive=/builds/worker/workspace/obj-build/debug/deps/libnum_derive-17ae033f2a4f5c06.so --extern num_integer=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnum_integer-1650408ea3c0d951.rmeta --extern num_traits=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnum_traits-9a6cae9489ff95d5.rmeta --extern num_cpus=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnum_cpus-ccc9e3f081936b97.rmeta --extern owning_ref=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libowning_ref-7ebb85ed13f7501b.rmeta --extern parking_lot=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libparking_lot-e45c344d5437d072.rmeta --extern precomputed_hash=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libprecomputed_hash-85a3506284bd479f.rmeta --extern rayon=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/librayon-b8085bb8d645fa01.rmeta --extern selectors=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libselectors-a0aa04cc4e45977b.rmeta --extern serde=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libserde-df0dc28cc3df50a2.rmeta --extern servo_arc=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libservo_arc-1e42323fa7a095d8.rmeta --extern smallbitvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsmallbitvec-3bce2f66af01de7e.rmeta --extern smallvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsmallvec-3a13bdb56ebd37f7.rmeta --extern static_prefs=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libstatic_prefs-2899311e77d460e6.rmeta --extern style_derive=/builds/worker/workspace/obj-build/debug/deps/libstyle_derive-7c3849b74084cf02.so --extern style_traits=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libstyle_traits-b5cd6ebde7fef198.rmeta --extern thin_slice=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libthin_slice-e0380efa964824d0.rmeta --extern time=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libtime-4683273ecf954d31.rmeta --extern to_shmem=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libto_shmem-0b84a39f356c258f.rmeta --extern to_shmem_derive=/builds/worker/workspace/obj-build/debug/deps/libto_shmem_derive-6430cf9a3200b526.so --extern uluru=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libuluru-fd7c58a9cc42a297.rmeta --extern unicode_bidi=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libunicode_bidi-a289c10d1fb60a7a.rmeta --extern unicode_segmentation=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libunicode_segmentation-596e1dcee891c45b.rmeta --extern void=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libvoid-fd9bb5055022000c.rmeta -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1`
[task 2021-01-16T18:45:00.973Z] 18:45:00     INFO -  warning: unnecessary parentheses around assigned value
[task 2021-01-16T18:45:00.973Z] 18:45:00     INFO -     --> /builds/worker/checkouts/gecko/third_party/rust/lucet-wasi-wasmsbx/src/host.rs:302:5
[task 2021-01-16T18:45:00.973Z] 18:45:00     INFO -      |
[task 2021-01-16T18:45:00.974Z] 18:45:00     INFO -  302 |     (RIGHTS_DIRECTORY_BASE | RIGHTS_REGULAR_FILE_BASE);
[task 2021-01-16T18:45:00.974Z] 18:45:00     INFO -      |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[task 2021-01-16T18:45:00.974Z] 18:45:00     INFO -      |
[task 2021-01-16T18:45:00.974Z] 18:45:00     INFO -      = note: `#[warn(unused_parens)]` on by default
[task 2021-01-16T18:45:00.974Z] 18:45:00     INFO -  warning: 1 warning emitted
[task 2021-01-16T18:45:00.975Z] 18:45:00     INFO -     Compiling rlbox_lucet_sandbox v0.1.0 (https://github.com/PLSysSec/rlbox_lucet_sandbox/?rev=f3cace4fb8b53db0849c62af4fa62bade5a620f7#f3cace4f)
[task 2021-01-16T18:45:00.978Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=rlbox_lucet_sandbox CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/third_party/rust/rlbox_lucet_sandbox CARGO_PKG_AUTHORS='shravanrn@gmail.com <shravanrn@gmail.com>' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE=MIT CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=rlbox_lucet_sandbox CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.1.0 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=1 CARGO_PKG_VERSION_PATCH=0 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name rlbox_lucet_sandbox --edition=2018 /builds/worker/checkouts/gecko/third_party/rust/rlbox_lucet_sandbox/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type rlib --crate-type staticlib --emit=dep-info,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on -C metadata=58f19831182e2032 -C extra-filename=-58f19831182e2032 --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern failure=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libfailure-211323c4aa809e0e.rlib --extern goblin=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libgoblin-32197af9f1f72cde.rlib --extern lucet_module=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblucet_module_wasmsbx-7b977c52fb787b2f.rlib --extern lucet_runtime_internals=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblucet_runtime_internals_wasmsbx-a5def1aee28f5c15.rlib --extern lucet_runtime=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblucet_runtime-d62b4aca3f49fa4a.rlib --extern lucet_wasi=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblucet_wasi-9654a17b24514c4b.rlib --cap-lints warn -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1 -L native=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/lucet-runtime-internals-wasmsbx-cfe6b56bf6fa316a/out -L native=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/lucet-runtime-internals-wasmsbx-cfe6b56bf6fa316a/out -L native=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/lucet-runtime-internals-wasmsbx-cfe6b56bf6fa316a/out -L native=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/libloading-d71c85464f3d32cd/out -L native=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/lucet-runtime-wasmsbx-08224c09c075edb6/out`
[task 2021-01-16T18:45:00.979Z] 18:45:00     INFO -     Compiling neqo-qpack v0.4.19 (https://github.com/mozilla/neqo?tag=v0.4.19#7bed9666)
[task 2021-01-16T18:45:00.982Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=neqo_qpack CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/third_party/rust/neqo-qpack CARGO_PKG_AUTHORS='Dragana Damjanovic <dragana.damjano@gmail.com>' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE=MIT/Apache-2.0 CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=neqo-qpack CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.4.19 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=4 CARGO_PKG_VERSION_PATCH=19 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name neqo_qpack --edition=2018 /builds/worker/checkouts/gecko/third_party/rust/neqo-qpack/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --cfg 'feature="default"' --cfg 'feature="deny-warnings"' -C metadata=f3d9964fc52120e0 -C extra-filename=-f3d9964fc52120e0 --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern lazy_static=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblazy_static-06a33473784416a3.rmeta --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern neqo_common=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_common-d0ef8b4e2e0b8983.rmeta --extern neqo_crypto=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_crypto-c7d99242cf537fde.rmeta --extern neqo_transport=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_transport-ed5f4d8a138d75c7.rmeta --extern qlog=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libqlog-24f2618ebc7ce3c1.rmeta --extern static_assertions=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libstatic_assertions-66cc1750d86ef3b5.rmeta --cap-lints warn -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1 -L native=/builds/worker/workspace/obj-build/dist/bin -L native=/builds/worker/workspace/obj-build/security/nss/lib/nss/nss_nss3 -L native=/builds/worker/workspace/obj-build/security/nss/lib/ssl/ssl_ssl3 -L native=/builds/worker/workspace/obj-build/config/external/nspr/pr`
[task 2021-01-16T18:45:00.982Z] 18:45:00     INFO -     Compiling fog v0.1.0 (/builds/worker/checkouts/gecko/toolkit/components/glean/api)
[task 2021-01-16T18:45:00.986Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=fog CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/toolkit/components/glean/api CARGO_PKG_AUTHORS='Glean SDK team <glean-team@mozilla.com>' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE='' CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=fog CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.1.0 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=1 CARGO_PKG_VERSION_PATCH=0 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name fog --edition=2018 toolkit/components/glean/api/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --cfg 'feature="nsstring"' --cfg 'feature="with_gecko"' --cfg 'feature="xpcom"' -C metadata=033ab77428e0ebe6 -C extra-filename=-033ab77428e0ebe6 --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern bincode=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libbincode-aac0253ddd56c7dd.rmeta --extern chrono=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libchrono-3378f905c5bf61e5.rmeta --extern glean=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libglean-6af7246aa5aee2d7.rmeta --extern glean_core=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libglean_core-f60842bd517240b1.rmeta --extern inherent=/builds/worker/workspace/obj-build/debug/deps/libinherent-0a01cfc5395e20fc.so --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern nsstring=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnsstring-1566dcdc2b7a5129.rmeta --extern once_cell=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libonce_cell-ed5c95591aedc89c.rmeta --extern serde=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libserde-df0dc28cc3df50a2.rmeta --extern thin_vec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libthin_vec-983507c8998ba9d2.rmeta --extern uuid=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libuuid-facb7bc9fdfa913f.rmeta --extern xpcom=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libxpcom-d7aa92848d482bbe.rmeta -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1 -L native=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/lmdb-rkv-sys-ef35cbab1d40dedb/out`
[task 2021-01-16T18:45:00.986Z] 18:45:00     INFO -     Compiling fxa-client v0.1.0 (https://github.com/mozilla/application-services?rev=8a576fbe79199fa8664f64285524017f74ebcc5f#8a576fbe)
[task 2021-01-16T18:45:00.991Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=fxa_client CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/third_party/rust/fxa-client CARGO_PKG_AUTHORS='Edouard Oger <eoger@fastmail.com>' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE=MPL-2.0 CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=fxa-client CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.1.0 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=1 CARGO_PKG_VERSION_PATCH=0 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name fxa_client --edition=2018 /builds/worker/checkouts/gecko/third_party/rust/fxa-client/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --cfg 'feature="default"' --cfg 'feature="gecko"' -C metadata=dae8adfdc039c8de -C extra-filename=-dae8adfdc039c8de --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern anyhow=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libanyhow-d7574b1ba9bae59a.rmeta --extern base64=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libbase64-bef30bde02f4935f.rmeta --extern error_support=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liberror_support-253149e492ab956b.rmeta --extern ffi_support=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libffi_support-823a97885e7d981b.rmeta --extern hex=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libhex-95f54ea87b470ed9.rmeta --extern jwcrypto=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libjwcrypto-a64caf48c2cf2d20.rmeta --extern lazy_static=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblazy_static-06a33473784416a3.rmeta --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern prost=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libprost-49cda4e23f38ff2a.rmeta --extern prost_derive=/builds/worker/workspace/obj-build/debug/deps/libprost_derive-d94bbdcab3fb54b2.so --extern rand_rccrypto=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/librand_rccrypto-dba12722e1b3a0f7.rmeta --extern rc_crypto=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/librc_crypto-0dda85b727d14f6c.rmeta --extern serde=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libserde-df0dc28cc3df50a2.rmeta --extern serde_derive=/builds/worker/workspace/obj-build/debug/deps/libserde_derive-6abe3eeb71ba8514.so --extern serde_json=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libserde_json-4db279a9a2d8064f.rmeta --extern sync_guid=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsync_guid-ff2d8913db114340.rmeta --extern sync15=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsync15-1582c85240656cdc.rmeta --extern thiserror=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libthiserror-00ed9d5208386542.rmeta --extern url=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liburl-0ec9398441f3ca06.rmeta --extern viaduct=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libviaduct-eb075937cffc4c12.rmeta --cap-lints warn -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1`
[task 2021-01-16T18:45:00.991Z] 18:45:00     INFO -     Compiling neqo-http3 v0.4.19 (https://github.com/mozilla/neqo?tag=v0.4.19#7bed9666)
[task 2021-01-16T18:45:00.995Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=neqo_http3 CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/third_party/rust/neqo-http3 CARGO_PKG_AUTHORS='Dragana Damjanovic <dragana.damjano@gmail.com>' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE=MIT/Apache-2.0 CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=neqo-http3 CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.4.19 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=4 CARGO_PKG_VERSION_PATCH=19 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name neqo_http3 --edition=2018 /builds/worker/checkouts/gecko/third_party/rust/neqo-http3/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --cfg 'feature="default"' --cfg 'feature="deny-warnings"' -C metadata=74d26f39a47d0c0c -C extra-filename=-74d26f39a47d0c0c --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern neqo_common=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_common-d0ef8b4e2e0b8983.rmeta --extern neqo_crypto=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_crypto-c7d99242cf537fde.rmeta --extern neqo_qpack=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_qpack-f3d9964fc52120e0.rmeta --extern neqo_transport=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_transport-ed5f4d8a138d75c7.rmeta --extern qlog=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libqlog-24f2618ebc7ce3c1.rmeta --extern smallvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsmallvec-3a13bdb56ebd37f7.rmeta --cap-lints warn -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1 -L native=/builds/worker/workspace/obj-build/dist/bin -L native=/builds/worker/workspace/obj-build/security/nss/lib/nss/nss_nss3 -L native=/builds/worker/workspace/obj-build/security/nss/lib/ssl/ssl_ssl3 -L native=/builds/worker/workspace/obj-build/config/external/nspr/pr`
[task 2021-01-16T18:45:00.995Z] 18:45:00     INFO -     Compiling neqo_glue v0.1.0 (/builds/worker/checkouts/gecko/netwerk/socket/neqo_glue)
[task 2021-01-16T18:45:00.999Z] 18:45:00     INFO -       Running `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=neqo_glue CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/netwerk/socket/neqo_glue CARGO_PKG_AUTHORS='Dragana Damjanovic <dd.mozilla@gmail.com>' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE='' CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=neqo_glue CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.1.0 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=1 CARGO_PKG_VERSION_PATCH=0 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name neqo_glue --edition=2018 netwerk/socket/neqo_glue/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on -C metadata=c549fceb5f1b8873 -C extra-filename=-c549fceb5f1b8873 --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern neqo_common=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_common-d0ef8b4e2e0b8983.rmeta --extern neqo_crypto=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_crypto-c7d99242cf537fde.rmeta --extern neqo_http3=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_http3-74d26f39a47d0c0c.rmeta --extern neqo_qpack=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_qpack-f3d9964fc52120e0.rmeta --extern neqo_transport=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libneqo_transport-ed5f4d8a138d75c7.rmeta --extern nserror=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnserror-bbd42ef885e3449c.rmeta --extern nsstring=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnsstring-1566dcdc2b7a5129.rmeta --extern qlog=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libqlog-24f2618ebc7ce3c1.rmeta --extern thin_vec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libthin_vec-983507c8998ba9d2.rmeta --extern xpcom=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libxpcom-d7aa92848d482bbe.rmeta -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1 -L native=/builds/worker/workspace/obj-build/dist/bin -L native=/builds/worker/workspace/obj-build/security/nss/lib/nss/nss_nss3 -L native=/builds/worker/workspace/obj-build/security/nss/lib/ssl/ssl_ssl3 -L native=/builds/worker/workspace/obj-build/config/external/nspr/pr`
[task 2021-01-16T18:45:01.000Z] 18:45:01     INFO -  error: unused import: `crate::stylesheets::Origin`
[task 2021-01-16T18:45:01.000Z] 18:45:01     INFO -     --> servo/components/style/stylesheets/document_rule.rs:282:13
[task 2021-01-16T18:45:01.000Z] 18:45:01     INFO -      |
[task 2021-01-16T18:45:01.000Z] 18:45:01     INFO -  282 |         use crate::stylesheets::Origin;
[task 2021-01-16T18:45:01.001Z] 18:45:01     INFO -      |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
[task 2021-01-16T18:45:01.001Z] 18:45:01     INFO -      |
[task 2021-01-16T18:45:01.001Z] 18:45:01     INFO -      = note: `-D unused-imports` implied by `-D warnings`
[task 2021-01-16T18:45:01.001Z] 18:45:01    ERROR -  error: aborting due to previous error
[task 2021-01-16T18:45:01.001Z] 18:45:01     INFO -  error: could not compile `style`
[task 2021-01-16T18:45:01.002Z] 18:45:01     INFO -  Caused by:
[task 2021-01-16T18:45:01.010Z] 18:45:01     INFO -    process didn't exit successfully: `CARGO=/builds/worker/fetches/rustc/bin/cargo CARGO_CRATE_NAME=style CARGO_MANIFEST_DIR=/builds/worker/checkouts/gecko/servo/components/style CARGO_PKG_AUTHORS='The Servo Project Developers' CARGO_PKG_DESCRIPTION='' CARGO_PKG_HOMEPAGE='' CARGO_PKG_LICENSE=MPL-2.0 CARGO_PKG_LICENSE_FILE='' CARGO_PKG_NAME=style CARGO_PKG_REPOSITORY='' CARGO_PKG_VERSION=0.0.1 CARGO_PKG_VERSION_MAJOR=0 CARGO_PKG_VERSION_MINOR=0 CARGO_PKG_VERSION_PATCH=1 CARGO_PKG_VERSION_PRE='' LD_LIBRARY_PATH='/builds/worker/workspace/obj-build/debug/deps:/builds/worker/fetches/rustc/lib:/builds/worker/workspace/obj-build/dist/bin:/builds/worker/fetches/clang/lib:/builds/worker/fetches/clang/lib32' OUT_DIR=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/build/style-2208e51312932126/out /builds/worker/fetches/sccache/sccache /builds/worker/fetches/rustc/bin/rustc --crate-name style --edition=2018 servo/components/style/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts --crate-type lib --emit=dep-info,metadata,link -C opt-level=1 -C panic=abort -C embed-bitcode=no -C debuginfo=2 -C debug-assertions=on --cfg 'feature="bindgen"' --cfg 'feature="gecko"' --cfg 'feature="gecko_debug"' --cfg 'feature="gecko_profiler"' --cfg 'feature="gecko_refcount_logging"' --cfg 'feature="nsstring"' --cfg 'feature="regex"' --cfg 'feature="serde"' --cfg 'feature="toml"' -C metadata=6d1c2008b56c2e7e -C extra-filename=-6d1c2008b56c2e7e --out-dir /builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps --target x86_64-unknown-linux-gnu -C linker=/builds/worker/checkouts/gecko/build/cargo-linker -L dependency=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps -L dependency=/builds/worker/workspace/obj-build/debug/deps --extern app_units=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libapp_units-45bc3bbb1d0cfc77.rmeta --extern arrayvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libarrayvec-b278ad1a4e8afa7e.rmeta --extern atomic_refcell=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libatomic_refcell-9e29407210814513.rmeta --extern bitflags=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libbitflags-3c52993b6e9c8f85.rmeta --extern byteorder=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libbyteorder-a709cab588b88216.rmeta --extern cssparser=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libcssparser-a48b826af352969a.rmeta --extern derive_more=/builds/worker/workspace/obj-build/debug/deps/libderive_more-58657d1461fa585f.so --extern euclid=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libeuclid-8e6df5e35d8376ab.rmeta --extern fallible=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libfallible-68149472bb410fe7.rmeta --extern fxhash=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libfxhash-26cd111602687ad5.rmeta --extern hashbrown=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libhashbrown-7ba21a05e60fdcb4.rmeta --extern hashglobe=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libhashglobe-7fa107c69cd44197.rmeta --extern indexmap=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libindexmap-f16b53fb18c2dc78.rmeta --extern itertools=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libitertools-bbbad24f578d65ff.rmeta --extern itoa=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libitoa-cbd5dfc4905fbd8f.rmeta --extern lazy_static=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblazy_static-06a33473784416a3.rmeta --extern log=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/liblog-dd650c826374f3d3.rmeta --extern malloc_size_of=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libmalloc_size_of-c525249a719ab41f.rmeta --extern malloc_size_of_derive=/builds/worker/workspace/obj-build/debug/deps/libmalloc_size_of_derive-6a504c736f6af2f5.so --extern matches=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libmatches-910515041b1a4296.rmeta --extern debug_unreachable=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libdebug_unreachable-6a799d2727fc4cea.rmeta --extern nsstring=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnsstring-1566dcdc2b7a5129.rmeta --extern num_derive=/builds/worker/workspace/obj-build/debug/deps/libnum_derive-17ae033f2a4f5c06.so --extern num_integer=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnum_integer-1650408ea3c0d951.rmeta --extern num_traits=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnum_traits-9a6cae9489ff95d5.rmeta --extern num_cpus=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libnum_cpus-ccc9e3f081936b97.rmeta --extern owning_ref=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libowning_ref-7ebb85ed13f7501b.rmeta --extern parking_lot=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libparking_lot-e45c344d5437d072.rmeta --extern precomputed_hash=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libprecomputed_hash-85a3506284bd479f.rmeta --extern rayon=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/librayon-b8085bb8d645fa01.rmeta --extern selectors=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libselectors-a0aa04cc4e45977b.rmeta --extern serde=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libserde-df0dc28cc3df50a2.rmeta --extern servo_arc=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libservo_arc-1e42323fa7a095d8.rmeta --extern smallbitvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsmallbitvec-3bce2f66af01de7e.rmeta --extern smallvec=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libsmallvec-3a13bdb56ebd37f7.rmeta --extern static_prefs=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libstatic_prefs-2899311e77d460e6.rmeta --extern style_derive=/builds/worker/workspace/obj-build/debug/deps/libstyle_derive-7c3849b74084cf02.so --extern style_traits=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libstyle_traits-b5cd6ebde7fef198.rmeta --extern thin_slice=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libthin_slice-e0380efa964824d0.rmeta --extern time=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libtime-4683273ecf954d31.rmeta --extern to_shmem=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libto_shmem-0b84a39f356c258f.rmeta --extern to_shmem_derive=/builds/worker/workspace/obj-build/debug/deps/libto_shmem_derive-6430cf9a3200b526.so --extern uluru=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libuluru-fd7c58a9cc42a297.rmeta --extern unicode_bidi=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libunicode_bidi-a289c10d1fb60a7a.rmeta --extern unicode_segmentation=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libunicode_segmentation-596e1dcee891c45b.rmeta --extern void=/builds/worker/workspace/obj-build/x86_64-unknown-linux-gnu/debug/deps/libvoid-fd9bb5055022000c.rmeta -C opt-level=2 -C debuginfo=2 -C force-frame-pointers=yes -Dwarnings -C codegen-units=1` (exit code: 1)
[task 2021-01-16T18:45:01.011Z] 18:45:01     INFO -  warning: build failed, waiting for other jobs to finish...
[task 2021-01-16T18:45:01.011Z] 18:45:01     INFO -  error: build failed
[task 2021-01-16T18:45:01.011Z] 18:45:01     INFO -  /builds/worker/checkouts/gecko/config/makefiles/rust.mk:326: recipe for target 'force-cargo-library-build' failed
[task 2021-01-16T18:45:01.011Z] 18:45:01    ERROR -  make[4]: *** [force-cargo-library-build] Error 101
[task 2021-01-16T18:45:01.012Z] 18:45:01     INFO -  make[4]: Leaving directory '/builds/worker/workspace/obj-build/toolkit/library/gtest/rust'
[task 2021-01-16T18:45:01.012Z] 18:45:01     INFO -  /builds/worker/checkouts/gecko/config/recurse.mk:72: recipe for target 'toolkit/library/gtest/rust/target' failed
[task 2021-01-16T18:45:01.012Z] 18:45:01    ERROR -  make[3]: *** [toolkit/library/gtest/rust/target] Error 2
[task 2021-01-16T18:45:01.013Z] 18:45:01     INFO -  make[3]: *** Waiting for unfinished jobs....

Grr, forgot to update my third commit again :(

https://hg.mozilla.org/mozilla-central/rev/252cbf40efcb
https://hg.mozilla.org/mozilla-central/rev/a6cd4b393999
https://hg.mozilla.org/mozilla-central/rev/f48f479bcacd

Thanks so much to everyone who worked on this! I'll test it as soon as it lands in beta (I assume a couple of weeks from now?)

You can try it already on a Nightly build

Backed out 3 changesets (bug 1551040) for Browser-chrome failures in browser/base/content/test/static/browser_parsable_css.js

Log:
https://treeherder.mozilla.org/logviewer?job_id=326959062&repo=autoland&lineNumber=3239

Push with failures:
https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&revision=f48f479bcacd31278efb0b9c1546d39f81de0940

Backout:
https://hg.mozilla.org/integration/autoland/rev/8539666101ed563877fca4a00e170afc1590f696

Now that resource:// stylesheets are parsing chrome rules, that test needs to be adjusted. Relanded with that fixed.

looks perfect emilio, thanks everyone.

can you correct me if i'm wrong? users can now style plaintext documents with:
@-moz-document plain-text-document() {
@media (prefers-color-scheme: dark) {
blah blah
}
}

and unobservable documents with:
@-moz-document unobservable-document() {
@media (prefers-color-scheme: dark) {
blah blah
}
}

and user sheets were already allowed to use this?
@-moz-document media-document(image) {
@media (prefers-color-scheme: dark) {
blah blah
}
}

Backout merged: https://hg.mozilla.org/mozilla-central/rev/8539666101ed

(In reply to aminomancer from comment #29)
That's right

https://hg.mozilla.org/mozilla-central/rev/aaccc06586f8
https://hg.mozilla.org/mozilla-central/rev/32394df21f46
https://hg.mozilla.org/mozilla-central/rev/b5766544144d
https://hg.mozilla.org/mozilla-central/rev/dcd9edd29856