fix: replace as-any casts with ErrorWithStatus interface

Define a file-local ErrorWithStatus interface matching upstream's
pattern (FetchDecompressionError) to eliminate all as-any casts.
Separate direct property extraction from JSON message fallback
to avoid double-parsing.

Author: okuyam2y

packages/opencode/src/session/message-v2.ts

@@ -22,6 +22,14 @@ interface FetchDecompressionError extends Error {
   path: string
 }
 
+/** Common shapes for non-APICallError provider errors carrying HTTP status */
+interface ErrorWithStatus {
+  status?: number
+  statusCode?: number
+  response?: { status?: number; statusCode?: number }
+  message?: string
+}
+
 export namespace MessageV2 {
   export function isMedia(mime: string) {
     return mime.startsWith("image/") || mime === "application/pdf"
@@ -991,28 +999,27 @@ export namespace MessageV2 {
         ).toObject()
       case e instanceof Error: {
         // Non-APICallError with HTTP status — treat 5xx as retryable.
+        const typed = e as Error & ErrorWithStatus
         const code =
-          (e as any).status ?? (e as any).statusCode ??
-          (e as any).response?.status ?? (e as any).response?.statusCode ??
-          (() => {
-            try {
-              const obj = JSON.parse(e.message)
-              return obj?.status ?? obj?.statusCode
-            } catch {
-              return undefined
-            }
-          })()
-        if (typeof code === "number" && code >= 500) {
-          let msg = e.message
-          try {
-            const obj = JSON.parse(msg)
-            if (typeof obj?.message === "string") msg = obj.message
-          } catch {}
+          typed.status ?? typed.statusCode ??
+          typed.response?.status ?? typed.response?.statusCode
+        if (typeof code === "number" && code >= 500)
           return new MessageV2.APIError(
-            { message: msg, statusCode: code, isRetryable: true },
+            { message: e.message, statusCode: code, isRetryable: true },
             { cause: e },
           ).toObject()
-        }
+        // Fallback: status may be embedded in a JSON error message.
+        try {
+          const obj = JSON.parse(e.message) as ErrorWithStatus
+          const jsonCode = obj?.status ?? obj?.statusCode
+          if (typeof jsonCode === "number" && jsonCode >= 500) {
+            const msg = typeof obj?.message === "string" ? obj.message : e.message
+            return new MessageV2.APIError(
+              { message: msg, statusCode: jsonCode, isRetryable: true },
+              { cause: e },
+            ).toObject()
+          }
+        } catch {}
         return new NamedError.Unknown({ message: e.message }, { cause: e }).toObject()
       }
       default:
@@ -1042,13 +1049,12 @@ export namespace MessageV2 {
         } catch {}
         // Plain-object 5xx — treat as retryable.
         if (typeof e === "object" && e !== null) {
-          const code =
-            (e as any).status ?? (e as any).statusCode ??
-            (e as any).response?.status ?? (e as any).response?.statusCode
+          const typed = e as ErrorWithStatus
+          const code = typed.status ?? typed.statusCode ?? typed.response?.status ?? typed.response?.statusCode
           if (typeof code === "number" && code >= 500)
             return new MessageV2.APIError(
               {
-                message: typeof (e as any).message === "string" ? (e as any).message : JSON.stringify(e),
+                message: typeof typed.message === "string" ? typed.message : JSON.stringify(e),
                 statusCode: code,
                 isRetryable: true,
               },