From 9134635b372753cd94f0ed57f354ba9ffc2348e2 Mon Sep 17 00:00:00 2001
From: zach <zach@dylibso.com>
Date: Mon, 25 Nov 2024 08:49:57 -0800
Subject: [PATCH] cleanup: return better errors for wasi command modules (#793)

---
 runtime/src/plugin.rs | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/runtime/src/plugin.rs b/runtime/src/plugin.rs
index af22b13..8718c61 100644
--- a/runtime/src/plugin.rs
+++ b/runtime/src/plugin.rs
@@ -906,8 +906,7 @@ impl Plugin {
             }
 
             // on extism error
-            if output_res.is_ok() && self.output.error_offset != 0 && self.output.error_length != 0
-            {
+            if output_res.is_ok() && self.extism_error_is_set() {
                 let handle = MemoryHandle {
                     offset: self.output.error_offset,
                     length: self.output.error_length,
@@ -927,7 +926,7 @@ impl Plugin {
                     }
                     Err(msg) => {
                         res = Err(Error::msg(format!(
-                            "Call to Extism plugin function {name} encountered an error: {}",
+                            "unable to load error message from memory: {}",
                             msg,
                         )));
                     }
@@ -994,11 +993,12 @@ impl Plugin {
                         plugin = self.id.to_string(),
                         "WASI exit code: {}", exit_code
                     );
-                    if exit_code == 0 {
+
+                    if exit_code == 0 && !self.extism_error_is_set() {
                         return Ok(0);
                     }
 
-                    return Err((e.context("WASI exit code"), exit_code));
+                    return Err((e, exit_code));
                 }
 
                 // Handle timeout interrupts
@@ -1026,6 +1026,10 @@ impl Plugin {
         }
     }
 
+    fn extism_error_is_set(&self) -> bool {
+        self.output.error_offset != 0 && self.output.error_length != 0
+    }
+
     /// Call a function by name with the given input, the return value is
     /// the output data returned by the plugin. The return type can be anything that implements
     /// [FromBytes]. This data will be invalidated next time the plugin is called.