add wasmtime trap information on function call errors, if available (#…

…620)
tessi · Dec 1, 2024 · a8a3bc5 · a8a3bc5
1 parent f0df3e8
commit a8a3bc5
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Showing 2 changed files with 18 additions and 6 deletions.
diff --git a/native/wasmex/src/instance.rs b/native/wasmex/src/instance.rs
@@ -19,7 +19,7 @@ use rustler::{
 use std::ops::Deref;
 use std::sync::Mutex;
 use std::thread;
-use wasmtime::{Instance, Linker, Module, Val, ValType};
+use wasmtime::{Instance, Linker, Module, Trap, Val, ValType};
 
 #[derive(NifMap)]
 pub struct LinkedModule {
@@ -289,8 +289,20 @@ fn execute_function(
     match call_result {
         Ok(_) => (),
         Err(err) => {
-            let reason = format!("Error during function excecution: `{err}`.");
-            return make_error_tuple(&thread_env, &reason, from);
+            let reason = format!("{err}");
+            if let Ok(trap) = err.downcast::<Trap>() {
+                return make_error_tuple(
+                    &thread_env,
+                    &format!("Error during function excecution ({trap}): {reason}"),
+                    from,
+                );
+            } else {
+                return make_error_tuple(
+                    &thread_env,
+                    &format!("Error during function excecution: {reason}"),
+                    from,
+                );
+            }
         }
     };
     let mut return_values: Vec<Term> = Vec::with_capacity(results_count);

diff --git a/test/wasmex_test.exs b/test/wasmex_test.exs
@@ -267,7 +267,7 @@ defmodule WasmexTest do
       assert {:error, reason} = Wasmex.call_function(instance, "using_imported_sum3", [1, 2, 3])
 
       assert reason =~
-               ~r/Error during function excecution: `error while executing at wasm backtrace:\n\s*0:\s*0x.* - .*\!using_imported_sum3`\./
+               ~r/Error during function excecution: error while executing at wasm backtrace:\n\s*0:\s*0x.* - .*\!using_imported_sum3/
     end
   end
 
@@ -287,7 +287,7 @@ defmodule WasmexTest do
 
       assert String.starts_with?(
                err_msg,
-               "Error during function excecution: `error while executing at wasm backtrace:"
+               "Error during function excecution (wasm trap: wasm `unreachable` instruction executed): error while executing at wasm backtrace:"
              )
     end
 
@@ -323,7 +323,7 @@ defmodule WasmexTest do
       assert {:error, err_msg} = Wasmex.call_function(pid, :void, [])
 
       assert err_msg =~
-               ~r/Error during function excecution: `error while executing at wasm backtrace:\n.+0:.+0x.+ - .*\!void`\./
+               ~r/Error during function excecution \(wasm trap: all fuel consumed by WebAssembly\): error while executing at wasm backtrace:\n.+0:.+0x.+ - .*\!void/
     end
   end