From bf9b601d7a91e4c505082099c2c16df1e3ca1789 Mon Sep 17 00:00:00 2001
From: Joshua Horton <jahorton@sil.org>
Date: Thu, 16 Jan 2025 08:36:23 +0700
Subject: [PATCH] change(web): keep transform pattern should match standard
 suggestion format

---
 .../worker-thread/src/main/predict-helpers.ts        | 12 +++++++-----
 .../src/tests/mocha/cases/suggestion-similarity.js   |  4 ++--
 .../src/tests/mocha/cases/worker-model-compositor.js |  4 ++--
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/web/src/engine/predictive-text/worker-thread/src/main/predict-helpers.ts b/web/src/engine/predictive-text/worker-thread/src/main/predict-helpers.ts
index a0b687b9bf..70f739611b 100644
--- a/web/src/engine/predictive-text/worker-thread/src/main/predict-helpers.ts
+++ b/web/src/engine/predictive-text/worker-thread/src/main/predict-helpers.ts
@@ -558,11 +558,13 @@ export function processSimilarity(
     return;
   }
 
-  // Generate a default 'keep' option if one was not otherwise produced.
-
-  // IMPORTANT:  duplicate the original transform.  Causes nasty side-effects
-  // for context-tracking otherwise!
-  let keepTransform: Transform = { ...inputTransform };
+  // Generate a full-word 'keep' replacement like other suggestions when one is not otherwise
+  // produced; we want to replace the full token in the same manner used for other suggestions.
+  const basePrefixLength = truePrefix.kmwLength() - inputTransform.insert.kmwLength() + inputTransform.deleteLeft;
+  const keepTransform = {
+    insert: truePrefix,
+    deleteLeft: basePrefixLength
+  };
 
   // 1 is a filler value; goes unused b/c is for a 'keep'.
   let keepSuggestion = models.transformToSuggestion(keepTransform, 1);
diff --git a/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/suggestion-similarity.js b/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/suggestion-similarity.js
index 7f31b1eff9..18fa1307b1 100644
--- a/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/suggestion-similarity.js
+++ b/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/suggestion-similarity.js
@@ -340,8 +340,8 @@ describe('processSimilarity', () => {
       prediction: {
         sample: {
           transform: {
-            insert: 'e',
-            deleteLeft: 0
+            insert: 'iphone',
+            deleteLeft: 5
           },
           displayAs: '<iphone>',
           matchesModel: false,
diff --git a/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/worker-model-compositor.js b/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/worker-model-compositor.js
index 8dc108440b..0774385026 100644
--- a/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/worker-model-compositor.js
+++ b/web/src/engine/predictive-text/worker-thread/src/tests/mocha/cases/worker-model-compositor.js
@@ -932,8 +932,8 @@ describe('ModelCompositor', function() {
       assert.equal(suggestions.length, 1);
 
       let expectedTransform = {
-        insert: ' ',  // Keeps current context the same, though it adds a wordbreak.
-        deleteLeft: 0
+        insert: 'hi ',  // Keeps current context the same, though it adds a wordbreak.
+        deleteLeft: 2
       }
       assert.deepEqual(suggestions[0].transform, expectedTransform);
     });