Fixed issue related to hang encountered when editing some lists (#343)

Proton/Sources/Swift/Core/LayoutManager.swift

@@ -88,26 +88,6 @@ class LayoutManager: NSLayoutManager {
             counters = [:]
         }
 
-        var levelToSet = 0
-        textStorage.enumerateAttribute(.paragraphStyle, in: listRange, options: []) { value, range, _ in
-            levelToSet = 0
-            if let paraStyle = (value as? NSParagraphStyle)?.mutableParagraphStyle {
-                let previousLevel = Int(prevStyle?.firstLineHeadIndent ?? 0)/Int(listIndent)
-                let currentLevel = Int(paraStyle.firstLineHeadIndent)/Int(listIndent)
-
-                if currentLevel - previousLevel > 1 {
-                    levelToSet = previousLevel + 1
-                    let indentation = CGFloat(levelToSet) * listIndent
-                    paraStyle.firstLineHeadIndent = indentation
-                    paraStyle.headIndent = indentation
-                    textStorage.addAttribute(.paragraphStyle, value: paraStyle, range: range)
-                    prevStyle = paraStyle
-                } else {
-                    prevStyle = value as? NSParagraphStyle
-                }
-            }
-        }
-
         let listGlyphRange = glyphRange(forCharacterRange: listRange, actualCharacterRange: nil)
         previousLevel = 0
         enumerateLineFragments(forGlyphRange: listGlyphRange) { [weak self] (rect, usedRect, textContainer, glyphRange, stop) in

Proton/Sources/Swift/EditorCommand/Commands/List/ListCommand.swift

@@ -104,6 +104,7 @@ public class ListCommand: EditorCommand {
             ], at: selectedRange)
             editor.removeAttribute(.listItem, at: selectedRange)
             editor.typingAttributes[.listItem] = nil
+            cleanupIfNeeded(editor: editor)
             return
         }
 
@@ -132,4 +133,34 @@ public class ListCommand: EditorCommand {
         self.attributeValue = attributeValue
         execute(on: editor)
     }
+
+    // Cleanup any dangling lists after the parent of this is removed as being a list item
+    private func cleanupIfNeeded(editor: EditorView) {
+        guard let nextContentLine = editor.nextContentLine(from: editor.selectedRange.endLocation),
+              nextContentLine.text.attributeOrNil(.listItem, at: 0) != nil,
+              let listToUpdateRange = editor.attributedText.rangeOf(attribute: .listItem, startingLocation: editor.selectedRange.endLocation) else { return }
+
+        let listIndent = editor.listLineFormatting.indentation
+
+        var levelToSet = 0
+        var prevStyle: NSParagraphStyle?
+        editor.attributedText.enumerateAttribute(.paragraphStyle, in: listToUpdateRange) { value, range, stop in
+            levelToSet = 0
+            if let paraStyle = (value as? NSParagraphStyle)?.mutableParagraphStyle {
+                let previousLevel = Int(prevStyle?.firstLineHeadIndent ?? 0)/Int(listIndent)
+                let currentLevel = Int(paraStyle.firstLineHeadIndent)/Int(listIndent)
+
+                if currentLevel - previousLevel > 1 {
+                    levelToSet = previousLevel + 1
+                    let indentation = CGFloat(levelToSet) * listIndent
+                    paraStyle.firstLineHeadIndent = indentation
+                    paraStyle.headIndent = indentation
+                    editor.addAttribute(.paragraphStyle, value: paraStyle, at: range)
+                    prevStyle = paraStyle
+                } else {
+                    prevStyle = value as? NSParagraphStyle
+                }
+            }
+        }
+    }
 }

Proton/Sources/Swift/Helpers/NSAttributedString+Range.swift

@@ -173,4 +173,28 @@ public extension NSAttributedString {
         let range = NSRange(location: searchTextRange.location, length: searchText.count)
         return range
     }
+
+    func attributedSubstringOrClamped(from range: NSRange) -> NSAttributedString {
+        let clamped = range.clamped(upperBound: length)
+        return attributedSubstring(from: clamped)
+    }
+
+    func substringOrClamped(from range: NSRange) -> String {
+        let clamped = range.clamped(upperBound: length)
+        return (string as NSString).substring(with: clamped)
+    }
+
+    func attributeOrNil(_ key: NSAttributedString.Key, at location: Int) -> Any? {
+        return attributesOrEmpty(at: location)[key]
+    }
+
+    func attributesOrEmpty(at location: Int) -> [NSAttributedString.Key: Any] {
+        guard self.length != 0, location >= 0, location < length else { return [:] }
+        return attributes(at: location, effectiveRange: nil)
+    }
+
+    func containsAttribute(_ key: NSAttributedString.Key, at location: Int) -> Bool {
+        attributesOrEmpty(at: location).keys.contains(key)
+    }
+
 }

Proton/Tests/Editor/EditorListsSnapshotTests.swift

@@ -594,10 +594,6 @@ class EditorListsSnapshotTests: SnapshotTestCase {
 
         viewController.render(size: CGSize(width: 300, height: 225))
         assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
-
-        // For some reason, a re-render is required in tests
-        viewController.render(size: CGSize(width: 300, height: 225))
-        assertSnapshot(matching: viewController.view, as: .image, record: recordMode)
     }
 
     func testRendersListWithDifferentAttributeValues() {