From 18f334a60e352f4c2f042e431cef2e9f769dd466 Mon Sep 17 00:00:00 2001
From: Joshua Horton <joshua_horton@sil.org>
Date: Wed, 9 Sep 2026 13:49:12 -0500
Subject: [PATCH] fix(web): handle 'unload' message while attempting model
 'load'

Fixes: KEYMAN-WEB-MD

Build-bot: skip build:web
Test-bot: skip
---
 .../predictive-text/worker-thread/src/main/index.ts | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/web/src/engine/predictive-text/worker-thread/src/main/index.ts b/web/src/engine/predictive-text/worker-thread/src/main/index.ts
index 262492674f..318256ba54 100644
--- a/web/src/engine/predictive-text/worker-thread/src/main/index.ts
+++ b/web/src/engine/predictive-text/worker-thread/src/main/index.ts
@@ -267,7 +267,11 @@ export class LMLayerWorker {
     try {
       this._importScripts(url);
     } catch (err) {
+      // Does not catch errors thrown within the imported script.
+      // Does catch errors with the model script's file-path.
       this.error("Error occurred when attempting to load dictionary", err);
+
+      // Remain in the model-unloaded state; the load attempt was unsuccessful.
     }
   }
 
@@ -312,7 +316,14 @@ export class LMLayerWorker {
     this.state = {
       name: 'modelless',
       handleMessage: (payload) => {
-        // ...that message must have been 'load'!
+        // It is possible to remain in this state after a model loading error.
+        // In such cases, the hosting engine may signal a model-unload.
+        if (payload.message === 'unload') {
+          // We are already in a "model unloaded" state; no work needed!
+          return;
+        }
+
+        // ...otherwise, that message must have been 'load'!
         if (payload.message !== 'load') {
           throw new Error(`invalid message; expected 'load' but got ${payload.message}`);
         }