Import: a model's left-out parts reach the user as an import warning

crates/engine/src/tests/session.rs

@@ -96,6 +96,25 @@ fn imported_files_go_into_the_comp_where_they_were_dropped() {
     assert!(s.execute("layer.addItem", json!({"item": "a.png", "position": [1.0]})).is_err(), "position needs x and y");
 }
 
+/// What an import left out of a file (a 3D model's textures over the limits) comes back in the
+/// import's `warnings`.
+#[test]
+fn what_an_import_left_out_is_a_warning() {
+    use effectcraft_project::{Footage, FootageKind};
+    struct Probe;
+    impl crate::Importer for Probe {
+        fn probe(&self, path: &str) -> Result<Footage, String> {
+            Ok(Footage { path: path.into(), kind: FootageKind::Model, ..Default::default() })
+        }
+        fn probe_noting(&self, path: &str) -> Result<(Footage, Option<String>), String> {
+            Ok((self.probe(path)?, Some(format!("{path}: texture `a.png` left out"))))
+        }
+    }
+    let mut s = Session { importer: Some(std::sync::Arc::new(Probe)), ..Default::default() };
+    let r = s.execute("file.import", json!({"paths": ["/m/scene.obj"]})).unwrap();
+    assert_eq!(r["warnings"], json!(["/m/scene.obj: texture `a.png` left out"]));
+}
+
 /// #270: files dropped or picked in the Import dialog (`file.import {background}`) are probed in
 /// a background job that says which file it is reading and how many are left; then they arrive
 /// in one undo step, all selected, with a count. The same file imported again arrives again.

crates/model/src/lib.rs

@@ -68,6 +68,11 @@ impl Texture {
     pub fn solid(c: [f32; 4]) -> Texture {
         Texture { width: 1, height: 1, data: vec![c], wrap: [Wrap::Repeat; 2] }
     }
+    /// The pixel size an image claims, read from its header without decoding it.
+    pub fn dimensions(bytes: &[u8]) -> Result<(u32, u32)> {
+        let reader = image::ImageReader::new(std::io::Cursor::new(bytes)).with_guessed_format().map_err(|e| perr(format!("image: {e}")))?;
+        reader.into_dimensions().map_err(|e| perr(format!("image: {e}")))
+    }
     /// Decode a PNG or JPEG.
     pub fn decode(bytes: &[u8]) -> Result<Texture> {
         let img = image::load_from_memory(bytes).map_err(|e| perr(format!("image: {e}")))?.to_rgba32f();