Fix inference conflict with serde_json through schemars feature (#…

…733)

Initially marking as a draft, because this currently just fiddles with
Cargo.toml to ensure that CI tests the feature.
this shouldn't actually require any changes to our CI scripts to
trigger, and as Daniel suggested, this uses a feature on with_winit
rather than vello itself.

Will follow up with the actual fix once I've confirmed CI fails.

---------

Co-authored-by: Daniel McNab <[email protected]>

Cargo.toml

@@ -44,7 +44,11 @@ vello_encoding = { version = "0.3.0", path = "vello_encoding" }
 vello_shaders = { version = "0.3.0", path = "vello_shaders" }
 bytemuck = { version = "1.18.0", features = ["derive"] }
 skrifa = "0.22.3"
+# The version of kurbo used below should be kept in sync
+# with the version of kurbo used by peniko.
 peniko = "0.2.0"
+# FIXME: This can be removed once peniko supports the schemars feature.
+kurbo = "0.11.1"
 futures-intrusive = "0.5.0"
 raw-window-handle = "0.6.2"
 smallvec = "1.13.2"

examples/with_winit/Cargo.toml

@@ -16,6 +16,8 @@ default = ["wgpu-profiler"]
 # Enable the use of wgpu-profiler. This is an optional feature for times when we use a git dependency on
 # wgpu (which means the dependency used in wgpu-profiler would be incompatible)
 wgpu-profiler = ["dep:wgpu-profiler", "vello/wgpu-profiler"]
+# Test for dependencies which implement std traits in ways that cause type inference issues.
+_ci_dep_features_to_test = ["dep:kurbo", "kurbo/schemars"]
 
 [lints]
 workspace = true
@@ -41,6 +43,8 @@ log = { workspace = true }
 # We're still using env-logger, but we want to use tracing spans to allow using
 # tracing_android_trace
 tracing = { version = "0.1.40", features = ["log-always"] }
+# For _ci_dep_features_to_test feature tests.
+kurbo = { workspace = true, optional = true }
 
 [target.'cfg(not(target_os = "android"))'.dependencies]
 # We use android_logger on Android

examples/with_winit/src/lib.rs

@@ -945,3 +945,12 @@ fn android_main(app: AndroidApp) {
 
     run(event_loop, args, scenes, render_cx);
 }
+
+#[cfg(all(feature = "_ci_dep_features_to_test", test))]
+#[test]
+// This just tests that the "kurbo" dependency we enable schemars for
+// aligns to the same version that vello's peniko dependency resolves to.
+fn test_kurbo_schemars_with_peniko() {
+    use std::marker::PhantomData;
+    let _: PhantomData<kurbo::Rect> = PhantomData::<vello::peniko::kurbo::Rect>;
+}

vello/src/scene.rs

@@ -536,7 +536,9 @@ impl<'a> DrawGlyphs<'a> {
                 EmojiLikeGlyph::Bitmap(bitmap) => {
                     let image = match bitmap.data {
                         bitmap::BitmapData::Bgra(data) => {
-                            if bitmap.width * bitmap.height * 4 != data.len().try_into().unwrap() {
+                            if bitmap.width * bitmap.height * 4
+                                != u32::try_from(data.len()).unwrap()
+                            {
                                 // TODO: Error once?
                                 log::error!("Invalid font");
                                 continue;