From ef04ab9ba998ccf9a2ca57d9c10b87b89bafff2d Mon Sep 17 00:00:00 2001
From: Jonatan Heyman <jonatan@heyman.info>
Date: Fri, 13 Jun 2025 12:52:42 +0200
Subject: [PATCH] Don't unfold folded region for changes on the same row as a
 folded region (but outside the fold), if the change doesn't actually insert
 anything, if the insertion is adding a new block, or if the change is
 undo/redo

---
 src/editor/annotation.js     |  4 ++++
 src/editor/block/commands.js |  6 ++++--
 src/editor/fold-gutter.js    | 21 +++++++++++++++++++++
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/editor/annotation.js b/src/editor/annotation.js
index ee8c07e..1401199 100644
--- a/src/editor/annotation.js
+++ b/src/editor/annotation.js
@@ -16,3 +16,7 @@ export const SET_FONT = "heynote-set-font"
 export function transactionsHasAnnotation(transactions, annotation) {
     return transactions.some(tr => tr.annotation(heynoteEvent) === annotation)
 }
+
+export function transactionsHasHistoryEvent(transactions) {
+    return transactions.some(tr => tr.isUserEvent("undo") || tr.isUserEvent("redo"))
+}
diff --git a/src/editor/block/commands.js b/src/editor/block/commands.js
index 9fa9212..bc2f1de 100644
--- a/src/editor/block/commands.js
+++ b/src/editor/block/commands.js
@@ -66,7 +66,8 @@ export const addNewBlockAfterCurrent = (editor) => ({ state, dispatch }) => {
             from: block.content.to,
             insert: delimText,
         },
-        selection: EditorSelection.cursor(block.content.to + delimText.length)
+        selection: EditorSelection.cursor(block.content.to + delimText.length),
+        annotations: [heynoteEvent.of(ADD_NEW_BLOCK)],
     }, {
         scrollIntoView: true,
         userEvent: "input",
@@ -106,7 +107,8 @@ export const addNewBlockAfterLast = (editor) => ({ state, dispatch }) => {
             from: block.content.to,
             insert: delimText,
         },
-        selection: EditorSelection.cursor(block.content.to + delimText.length)
+        selection: EditorSelection.cursor(block.content.to + delimText.length),
+        annotations: [heynoteEvent.of(ADD_NEW_BLOCK)],
     }, {
         scrollIntoView: true,
         userEvent: "input",
diff --git a/src/editor/fold-gutter.js b/src/editor/fold-gutter.js
index 642fbe5..11dbe25 100644
--- a/src/editor/fold-gutter.js
+++ b/src/editor/fold-gutter.js
@@ -4,10 +4,15 @@ import { RangeSet } from "@codemirror/state"
 
 import { FOLD_LABEL_LENGTH } from "@/src/common/constants.js"
 import { getNoteBlockFromPos } from "./block/block.js"
+import { transactionsHasAnnotation, ADD_NEW_BLOCK, transactionsHasHistoryEvent } from "./annotation.js"
 
 
 // This extension fixes so that a folded region is automatically unfolded if any changes happen 
 // on either the start line or the end line of the folded region (even if the change is not within the folded region)
+// except for if the change is an insertion of a new block, or if the change doesn't actually insert anything.
+// 
+// The purpose is to prevent extra characters to be inserted into a line that is folded, without the region
+// being unfolded.
 const autoUnfoldOnEdit = () => {
     return EditorView.updateListener.of((update) => {
         if (!update.docChanged){
@@ -20,6 +25,22 @@ const autoUnfoldOnEdit = () => {
         if (!foldRanges || foldRanges.size === 0) {
             return
         }
+        
+        // we don't want to unfold a block/range if the user adds a new block
+        if (transactionsHasAnnotation(update.transactions, ADD_NEW_BLOCK)) {
+            return
+        }
+        // an undo/redo action should never be able to get characters into a folded line but if we don't have 
+        // this check an undo/redo of a block insertion before/after the region will unfold the folded block
+        if (transactionsHasHistoryEvent(update.transactions)) {
+            return
+        }
+        
+        // This fixes so that removing the previous block immediately after a folded block won't unfold the folded block
+        // Since nothing was inserted, there is no risk of us putting extra characters into folded lines
+        if (update.changes.inserted.length === 0) {
+            return
+        }
 
         const unfoldRanges = []