Merge pull request #1179 from alexcrichton/catch-all-errors

In debug mode log all imported uncaught exceptions

crates/cli-support/src/js/mod.rs

@@ -2420,6 +2420,9 @@ impl<'a, 'b> SubContext<'a, 'b> {
         // Build up our shim's state, and we'll use that to guide whether we
         // actually emit an import here or not.
         let mut shim = Rust2Js::new(self.cx);
+        if shim.cx.config.debug {
+            shim.catch_and_rethrow(true);
+        }
         shim.catch(import.catch)
             .variadic(import.variadic)
             .process(descriptor.unwrap_function())?;

crates/cli-support/src/js/rust2js.rs

@@ -36,6 +36,7 @@ pub struct Rust2Js<'a, 'b: 'a> {
 
     /// Whether or not we're catching JS exceptions
     catch: bool,
+    catch_and_rethrow: bool,
 
     /// Whether or not the last argument is a slice representing variadic arguments.
     variadic: bool,
@@ -53,6 +54,7 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
             arg_idx: 0,
             ret_expr: String::new(),
             catch: false,
+            catch_and_rethrow: false,
             variadic: false,
         }
     }
@@ -62,6 +64,11 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
         self
     }
 
+    pub fn catch_and_rethrow(&mut self, catch_and_rethrow: bool) -> &mut Self {
+        self.catch_and_rethrow = catch_and_rethrow;
+        self
+    }
+
     pub fn variadic(&mut self, variadic: bool) -> &mut Self {
         self.variadic = variadic;
         self
@@ -505,6 +512,7 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
         let Rust2Js {
             // fields which may affect whether we do nontrivial work
             catch,
+            catch_and_rethrow,
             finally,
             js_arguments,
             prelude,
@@ -520,6 +528,7 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
         } = self;
 
         !catch &&
+            !catch_and_rethrow &&
             !variadic &&
             prelude.is_empty() &&
             finally.is_empty() &&
@@ -639,7 +648,21 @@ impl<'a, 'b> Rust2Js<'a, 'b> {
                 ",
                 &invoc, catch
             );
-        };
+        } else if self.catch_and_rethrow {
+            invoc = format!(
+                "\
+                try {{\n\
+                    {}
+                }} catch (e) {{\n\
+                    console.error(\"wasm-bindgen: imported JS function that \
+                                    was not marked as `catch` threw an error:\", \
+                                    e);
+                    throw e;
+                }}\
+                ",
+                &invoc,
+            );
+        }
 
         if self.finally.len() > 0 {
             invoc = format!(