From bf652fb18c77414545112e0367e5c308b0727d63 Mon Sep 17 00:00:00 2001
From: Eberhard Beilharz <eb1@sil.org>
Date: Fri, 28 Nov 2025 12:03:11 +0100
Subject: [PATCH] fix(web): another simplification

Plus another unit test.

Test-bot: skip
---
 .../core-processor/coreKeyboardProcessor.ts   | 30 +++++++----------
 .../coreKeyboardProcessor.tests.ts            | 32 +++++++++++++++++++
 2 files changed, 44 insertions(+), 18 deletions(-)

diff --git a/web/src/engine/src/core-processor/coreKeyboardProcessor.ts b/web/src/engine/src/core-processor/coreKeyboardProcessor.ts
index a6f4b19f28..85bba45178 100644
--- a/web/src/engine/src/core-processor/coreKeyboardProcessor.ts
+++ b/web/src/engine/src/core-processor/coreKeyboardProcessor.ts
@@ -177,32 +177,26 @@ export class CoreKeyboardProcessor extends EventEmitter<EventMap> implements Key
 
     const deadkeyIterator = deadkeys.values();
     let deadkey = deadkeyIterator.next();
-    const textMax = Math.min(text.length, caretPosition + 1);
     let textIndex = 0;
-    while (!deadkey.done || textIndex < textMax) {
-      // insert 0 or more deadkeys at current index
-      while (!deadkey.done && deadkey.value.p <= textIndex) {
-        if (deadkey.value.p < textIndex) {
-          // this should never happen -- it would mean that
-          // a deadkey position was < 0 or in the middle of a
-          // surrogate pair. We'll silently drop it
-          console.warn(`invalid deadkey '${deadkey.value.d}' position ${deadkey.value.p}`);
-        } else {
-          const contextItem = new KM_Core.instance.km_core_context_item();
-          contextItem.marker = deadkey.value.d;
-          contextItems.push_back(contextItem);
-        }
+    while (!deadkey.done || textIndex < text.length) {
+      // flush out invalid deadkeys
+      while (!deadkey.done && (deadkey.value.p < textIndex || deadkey.value.p > text.length)) {
+        // this should never happen -- it would mean that a deadkey position was < 0, in the
+        // middle of a surrogate pair, or after the caret.
+        console.warn(`invalid deadkey '${deadkey.value.d}' position ${deadkey.value.p}`);
         deadkey = deadkeyIterator.next();
       }
 
-      // flush out invalid deadkeys
-      while (!deadkey.done && deadkey.value.p > textMax) {
-        console.warn(`invalid deadkey '${deadkey.value.d}' position ${deadkey.value.p} after end of text ${textMax}`);
+      // insert 0 or more deadkeys at current index
+      while (!deadkey.done && deadkey.value.p == textIndex) {
+        const contextItem = new KM_Core.instance.km_core_context_item();
+        contextItem.marker = deadkey.value.d;
+        contextItems.push_back(contextItem);
         deadkey = deadkeyIterator.next();
       }
 
       // insert next character
-      if (textIndex < textMax) {
+      if (textIndex < text.length) {
         const contextItem = new KM_Core.instance.km_core_context_item();
         contextItem.character = text.codePointAt(textIndex);
         contextItems.push_back(contextItem);
diff --git a/web/src/test/auto/headless/engine/core-processor/coreKeyboardProcessor.tests.ts b/web/src/test/auto/headless/engine/core-processor/coreKeyboardProcessor.tests.ts
index 4c1ea84317..8090308eb6 100644
--- a/web/src/test/auto/headless/engine/core-processor/coreKeyboardProcessor.tests.ts
+++ b/web/src/test/auto/headless/engine/core-processor/coreKeyboardProcessor.tests.ts
@@ -454,5 +454,37 @@ describe('CoreKeyboardProcessor', function () {
       assert.equal(items.get(2).type, KM_CORE_CT.END, 'Item 2 should be END');
       result.delete();
     });
+
+    it('skips invalid deadkeys', function () {
+      // Setup
+      textStore = new SyntheticTextStore('abcde', 3);
+      textStore.deadkeys().add(new Deadkey(-1, 1)); // invalid
+      textStore.deadkeys().add(new Deadkey(1, 2));  // after 'b'
+      textStore.deadkeys().add(new Deadkey(4, 3));  // invalid (after caret)
+
+      // Execute
+      coreProcessor.unitTestEndPoints.applyContextFromTextStore(context, textStore);
+
+      // Verify
+      const result = KM_Core.instance.context_get(context);
+      assert.equal(result.status, KM_CORE_STATUS.OK);
+      const items = result.object;
+
+      // Text index   : 0 1   1 2 3
+      // Text:        :           |
+      // context index: 0 1   2 3 4
+      // ContextItems : a dk2 b c END
+      assert.equal(items.size(), 5, 'Should have 5 context items');
+      assert.equal(items.get(0).type, KM_CORE_CT.CHAR, 'Item 0 should be CHAR');
+      assert.equal(items.get(0).character, 'a'.charCodeAt(0), 'Item 0 should be "a"');
+      assert.equal(items.get(1).type, KM_CORE_CT.MARKER, 'Item 1 should be MARKER');
+      assert.equal(items.get(1).marker, 2, 'Item 1 should be marker 2');
+      assert.equal(items.get(2).type, KM_CORE_CT.CHAR, 'Item 2 should be CHAR');
+      assert.equal(items.get(2).character, 'b'.charCodeAt(0), 'Item 2 should be "b"');
+      assert.equal(items.get(3).type, KM_CORE_CT.CHAR, 'Item 3 should be CHAR');
+      assert.equal(items.get(3).character, 'c'.charCodeAt(0), 'Item 3 should be "c"');
+      assert.equal(items.get(4).type, KM_CORE_CT.END, 'Item 4 should be END');
+      result.delete();
+    });
   });
 });