Propagate errors in preprocess instead of unwrapping (#1648)

Closes #1647

Author: alexcrichton

crates/c/src/lib.rs

@@ -173,7 +173,7 @@ enum Scalar {
 }
 
 impl WorldGenerator for C {
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> Result<()> {
         self.world = self
             .opts
             .rename_world
@@ -204,6 +204,7 @@ impl WorldGenerator for C {
                 }
             }
         }
+        Ok(())
     }
 
     fn import_interface(

crates/core/src/lib.rs

@@ -28,7 +28,7 @@ pub trait WorldGenerator {
             resolve.generate_nominal_type_ids(id);
         }
         let world = &resolve.worlds[id];
-        self.preprocess(resolve, id);
+        self.preprocess(resolve, id)?;
 
         fn unwrap_name(key: &WorldKey) -> &str {
             match key {
@@ -95,8 +95,9 @@ pub trait WorldGenerator {
         let _ = (resolve, world, files);
     }
 
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> Result<()> {
         let _ = (resolve, world);
+        Ok(())
     }
 
     fn import_interface(

crates/cpp/src/lib.rs

@@ -487,7 +487,7 @@ struct FileContext {
 }
 
 impl WorldGenerator for Cpp {
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> anyhow::Result<()> {
         let name = &resolve.worlds[world].name;
         self.world = name.to_string();
         self.types.analyze(resolve);
@@ -511,6 +511,7 @@ impl WorldGenerator for Cpp {
             "#,
             self.world.to_snake_case(),
         );
+        Ok(())
     }
 
     fn import_interface(

crates/csharp/src/world_generator.rs

@@ -144,7 +144,7 @@ impl CSharp {
 }
 
 impl WorldGenerator for CSharp {
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> anyhow::Result<()> {
         let name = &resolve.worlds[world].name;
         self.types.analyze(resolve);
         self.types.collect_equal_types(resolve, world, &|a| {
@@ -171,6 +171,7 @@ impl WorldGenerator for CSharp {
         });
         self.name = name.to_string();
         self.sizes.fill(resolve);
+        Ok(())
     }
 
     fn import_interface(

crates/go/src/lib.rs

@@ -724,10 +724,11 @@ impl WorldGenerator for Go {
         false
     }
 
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> Result<()> {
         _ = world;
         self.sizes.fill(resolve);
         self.imports.insert(remote_pkg("runtime"));
+        Ok(())
     }
 
     fn import_interface(

crates/markdown/src/lib.rs

@@ -37,7 +37,7 @@ impl Opts {
 }
 
 impl WorldGenerator for Markdown {
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> Result<()> {
         self.sizes.fill(resolve);
 
         let world = &resolve.worlds[world];
@@ -109,6 +109,7 @@ impl WorldGenerator for Markdown {
             }
         }
         r#gen.push_str("\n");
+        Ok(())
     }
 
     fn import_interface(

crates/moonbit/src/lib.rs

@@ -244,7 +244,7 @@ impl MoonBit {
 /// - Inline FFI helpers and builtins are collected and written once into the
 ///   final export FFI module. Async helpers are emitted when required.
 impl WorldGenerator for MoonBit {
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> Result<()> {
         self.pkg_resolver.resolve = resolve.clone();
         self.project_name = self
             .opts
@@ -256,6 +256,7 @@ impl WorldGenerator for MoonBit {
             }))
             .unwrap_or("generated".into());
         self.sizes.fill(resolve);
+        Ok(())
     }
 
     fn import_interface(

crates/rust/src/lib.rs

@@ -1069,7 +1069,7 @@ macro_rules! __export_{world_name}_impl {{
 }
 
 impl WorldGenerator for RustWasm {
-    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) {
+    fn preprocess(&mut self, resolve: &Resolve, world: WorldId) -> Result<()> {
         wit_bindgen_core::generated_preamble(&mut self.src_preamble, env!("CARGO_PKG_VERSION"));
 
         // Render some generator options to assist with debugging and/or to help
@@ -1239,14 +1239,15 @@ impl WorldGenerator for RustWasm {
         self.with.generate_by_default = self.opts.generate_all;
         for (key, item) in world.imports.iter() {
             if let WorldItem::Interface { id, .. } = item {
-                self.name_interface(resolve, *id, &key, false).unwrap();
+                self.name_interface(resolve, *id, &key, false)?;
             }
         }
         for (key, item) in world.exports.iter() {
             if let WorldItem::Interface { id, .. } = item {
-                self.name_interface(resolve, *id, &key, true).unwrap();
+                self.name_interface(resolve, *id, &key, true)?;
             }
         }
+        Ok(())
     }
 
     fn import_interface(