From 164b38f0cd10118d1f3ff8ae11daff03e657ec9e Mon Sep 17 00:00:00 2001
From: Jeremy Nicholl <jeremy.nicholl@bluescape.com>
Date: Mon, 31 Jan 2022 14:49:16 -0500
Subject: [PATCH 1/3] Avoid copying attribute map when deleting

Calling cleanupFormattingGap should not make a copy of the
attributes because it needs to be able to update them.
---
 src/types/YText.js    |  2 +-
 tests/y-text.tests.js | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/types/YText.js b/src/types/YText.js
index 328795e0..8e505f5a 100644
--- a/src/types/YText.js
+++ b/src/types/YText.js
@@ -465,7 +465,7 @@ const deleteText = (transaction, currPos, length) => {
     currPos.forward()
   }
   if (start) {
-    cleanupFormattingGap(transaction, start, currPos.right, startAttrs, map.copy(currPos.currentAttributes))
+    cleanupFormattingGap(transaction, start, currPos.right, startAttrs, currPos.currentAttributes)
   }
   const parent = /** @type {AbstractType<any>} */ (/** @type {Item} */ (currPos.left || currPos.right).parent)
   if (parent._searchMarker) {
diff --git a/tests/y-text.tests.js b/tests/y-text.tests.js
index 2a555237..0ca9a879 100644
--- a/tests/y-text.tests.js
+++ b/tests/y-text.tests.js
@@ -138,6 +138,28 @@ export const testNotMergeEmptyLinesFormat = tc => {
   ])
 }
 
+/**
+ * @param {t.TestCase} tc
+ */
+export const testPreserveAttributesThroughDelete = tc => {
+  const ydoc = new Y.Doc()
+  const testText = ydoc.getText('test');
+  testText.applyDelta([
+    { insert: 'Text' },
+    { insert: '\n', attributes: { title: true } },
+    { insert: '\n' }
+  ])
+  testText.applyDelta([
+    { retain: 4 },
+    { delete: 1 },
+    { retain: 1, attributes: { title: true } },
+  ])
+  t.compare(testText.toDelta(), [
+    { insert: 'Text' },
+    { insert: '\n', attributes: { title: true } },
+  ])
+}
+
 /**
  * @param {t.TestCase} tc
  */

From 84e95f11cb9bdae13f3c4af3625efdc85990bfff Mon Sep 17 00:00:00 2001
From: Jeremy Nicholl <jeremy.nicholl@bluescape.com>
Date: Thu, 3 Feb 2022 15:19:57 -0500
Subject: [PATCH 2/3] Fix formatting

---
 tests/y-text.tests.js | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tests/y-text.tests.js b/tests/y-text.tests.js
index 0ca9a879..7a8c448a 100644
--- a/tests/y-text.tests.js
+++ b/tests/y-text.tests.js
@@ -143,7 +143,7 @@ export const testNotMergeEmptyLinesFormat = tc => {
  */
 export const testPreserveAttributesThroughDelete = tc => {
   const ydoc = new Y.Doc()
-  const testText = ydoc.getText('test');
+  const testText = ydoc.getText('test')
   testText.applyDelta([
     { insert: 'Text' },
     { insert: '\n', attributes: { title: true } },
@@ -152,11 +152,11 @@ export const testPreserveAttributesThroughDelete = tc => {
   testText.applyDelta([
     { retain: 4 },
     { delete: 1 },
-    { retain: 1, attributes: { title: true } },
+    { retain: 1, attributes: { title: true } }
   ])
   t.compare(testText.toDelta(), [
     { insert: 'Text' },
-    { insert: '\n', attributes: { title: true } },
+    { insert: '\n', attributes: { title: true } }
   ])
 }
 

From 2d1e3fde43965940d019a0d3279348a2fded7c42 Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@pm.me>
Date: Fri, 4 Feb 2022 11:26:32 +0100
Subject: [PATCH 3/3] fixed edge formatting case

---
 src/types/YText.js | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/types/YText.js b/src/types/YText.js
index 8e505f5a..c0339003 100644
--- a/src/types/YText.js
+++ b/src/types/YText.js
@@ -338,14 +338,16 @@ const formatText = (transaction, parent, currPos, length, attributes) => {
  *
  * @param {Transaction} transaction
  * @param {Item} start
- * @param {Item|null} end exclusive end, automatically iterates to the next Content Item
+ * @param {Item|null} curr exclusive end, automatically iterates to the next Content Item
  * @param {Map<string,any>} startAttributes
- * @param {Map<string,any>} endAttributes This attribute is modified!
+ * @param {Map<string,any>} currAttributes
  * @return {number} The amount of formatting Items deleted.
  *
  * @function
  */
-const cleanupFormattingGap = (transaction, start, end, startAttributes, endAttributes) => {
+const cleanupFormattingGap = (transaction, start, curr, startAttributes, currAttributes) => {
+  let end = curr
+  const endAttributes = map.copy(currAttributes)
   while (end && (!end.countable || end.deleted)) {
     if (!end.deleted && end.content.constructor === ContentFormat) {
       updateCurrentAttributes(endAttributes, /** @type {ContentFormat} */ (end.content))
@@ -353,7 +355,11 @@ const cleanupFormattingGap = (transaction, start, end, startAttributes, endAttri
     end = end.right
   }
   let cleanups = 0
+  let reachedEndOfCurr = false
   while (start !== end) {
+    if (curr === start) {
+      reachedEndOfCurr = true
+    }
     if (!start.deleted) {
       const content = start.content
       switch (content.constructor) {
@@ -363,6 +369,9 @@ const cleanupFormattingGap = (transaction, start, end, startAttributes, endAttri
             // Either this format is overwritten or it is not necessary because the attribute already existed.
             start.delete(transaction)
             cleanups++
+            if (!reachedEndOfCurr && (currAttributes.get(key) || null) === value) {
+              currAttributes.delete(key)
+            }
           }
           break
         }