Fix End Of Doc Crash (#285)

Example/CodeEditSourceEditorExample/CodeEditSourceEditorExample.xcodeproj/xcshareddata/xcschemes/CodeEditSourceEditorExample.xcscheme

@@ -29,6 +29,18 @@
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       shouldUseLaunchSchemeArgsEnv = "YES"
       shouldAutocreateTestPlan = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "CodeEditSourceEditorTests"
+               BuildableName = "CodeEditSourceEditorTests"
+               BlueprintName = "CodeEditSourceEditorTests"
+               ReferencedContainer = "container:../..">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
    </TestAction>
    <LaunchAction
       buildConfiguration = "Debug"

Sources/CodeEditSourceEditor/Highlighting/StyledRangeContainer/StyledRangeStore/StyledRangeStore+Internals.swift → Sources/CodeEditSourceEditor/Highlighting/StyledRangeContainer/StyledRangeStore/StyledRangeStore+Coalesce.swift

@@ -7,15 +7,6 @@
 
 import _RopeModule
 
-extension StyledRangeStore {
-    /// Finds a Rope index, given a string offset.
-    /// - Parameter offset: The offset to query for.
-    /// - Returns: The index of the containing element in the rope.
-    func findIndex(at offset: Int) -> (index: Index, remaining: Int) {
-        _guts.find(at: offset, in: OffsetMetric(), preferEnd: false)
-    }
-}
-
 extension StyledRangeStore {
     /// Coalesce items before and after the given range.
     ///
@@ -32,7 +23,7 @@ extension StyledRangeStore {
         }
 
         index = findIndex(at: range.lowerBound).index
-        if index > _guts.startIndex && _guts.count > 1 {
+        if index > _guts.startIndex && index < _guts.endIndex && _guts.count > 1 {
             index = _guts.index(before: index)
             coalesceRunAfter(index: &index)
         }

Sources/CodeEditSourceEditor/Highlighting/StyledRangeContainer/StyledRangeStore/StyledRangeStore+FindIndex.swift

@@ -0,0 +1,15 @@
+//
+//  StyledRangeStore+FindIndex.swift
+//  CodeEditSourceEditor
+//
+//  Created by Khan Winter on 1/6/25.
+//
+
+extension StyledRangeStore {
+    /// Finds a Rope index, given a string offset.
+    /// - Parameter offset: The offset to query for.
+    /// - Returns: The index of the containing element in the rope.
+    func findIndex(at offset: Int) -> (index: Index, remaining: Int) {
+        _guts.find(at: offset, in: OffsetMetric(), preferEnd: false)
+    }
+}

Tests/CodeEditSourceEditorTests/Highlighting/HighlighterTests.swift

@@ -38,12 +38,30 @@ final class HighlighterTests: XCTestCase {
         func attributesFor(_ capture: CaptureName?) -> [NSAttributedString.Key: Any] { [:] }
     }
 
+    class SentryStorageDelegate: NSObject, NSTextStorageDelegate {
+        var editedIndices: IndexSet = IndexSet()
+
+        func textStorage(
+            _ textStorage: NSTextStorage,
+            didProcessEditing editedMask: NSTextStorageEditActions,
+            range editedRange: NSRange,
+            changeInLength delta: Int) {
+                editedIndices.insert(integersIn: editedRange)
+            }
+    }
+
+    var attributeProvider: MockAttributeProvider!
+    var textView: TextView!
+
+    override func setUp() {
+        attributeProvider = MockAttributeProvider()
+        textView = Mock.textView()
+        textView.frame = NSRect(x: 0, y: 0, width: 1000, height: 1000)
+    }
+
     @MainActor
     func test_canceledHighlightsAreInvalidated() {
         let highlightProvider = MockHighlightProvider()
-        let attributeProvider = MockAttributeProvider()
-        let textView = Mock.textView()
-        textView.frame = NSRect(x: 0, y: 0, width: 1000, height: 1000)
         textView.setText("Hello World!")
         let highlighter = Mock.highlighter(
             textView: textView,
@@ -62,23 +80,8 @@ final class HighlighterTests: XCTestCase {
 
     @MainActor
     func test_highlightsDoNotInvalidateEntireTextView() {
-        class SentryStorageDelegate: NSObject, NSTextStorageDelegate {
-            var editedIndices: IndexSet = IndexSet()
-
-            func textStorage(
-                _ textStorage: NSTextStorage,
-                didProcessEditing editedMask: NSTextStorageEditActions,
-                range editedRange: NSRange,
-                changeInLength delta: Int) {
-                editedIndices.insert(integersIn: editedRange)
-            }
-        }
-
         let highlightProvider = TreeSitterClient()
         highlightProvider.forceSyncOperation = true
-        let attributeProvider = MockAttributeProvider()
-        let textView = Mock.textView()
-        textView.frame = NSRect(x: 0, y: 0, width: 1000, height: 1000)
         textView.setText("func helloWorld() {\n\tprint(\"Hello World!\")\n}")
 
         let highlighter = Mock.highlighter(
@@ -97,4 +100,49 @@ final class HighlighterTests: XCTestCase {
 
         XCTAssertEqual(sentryStorage.editedIndices, invalidSet) // Should only cause highlights on the first line
     }
+
+    // This test isn't testing much highlighter functionality. However, we've seen crashes and other errors after normal
+    // editing that were caused by the highlighter and would only have been caught by an integration test like this.
+    @MainActor
+    func test_editFile() {
+        let highlightProvider = TreeSitterClient()
+        highlightProvider.forceSyncOperation = true
+        textView.setText("func helloWorld() {\n\tprint(\"Hello World!\")\n}") // 44 chars
+
+        let highlighter = Mock.highlighter(
+            textView: textView,
+            highlightProvider: highlightProvider,
+            attributeProvider: attributeProvider
+        )
+        textView.addStorageDelegate(highlighter)
+        highlighter.setLanguage(language: .swift)
+        highlighter.invalidate()
+
+        // Delete Characters
+        textView.replaceCharacters(in: [NSRange(location: 43, length: 1)], with: "")
+        textView.replaceCharacters(in: [NSRange(location: 0, length: 4)], with: "")
+        textView.replaceCharacters(in: [NSRange(location: 6, length: 5)], with: "")
+        textView.replaceCharacters(in: [NSRange(location: 25, length: 5)], with: "")
+
+        XCTAssertEqual(textView.string, " hello() {\n\tprint(\"Hello !\")\n")
+
+        // Insert Characters
+        textView.replaceCharacters(in: [NSRange(location: 29, length: 0)], with: "}")
+        textView.replaceCharacters(
+            in: [NSRange(location: 25, length: 0), NSRange(location: 6, length: 0)],
+            with: "World"
+        )
+        // emulate typing with a cursor
+        textView.selectionManager.setSelectedRange(NSRange(location: 0, length: 0))
+        textView.insertText("f")
+        textView.insertText("u")
+        textView.insertText("n")
+        textView.insertText("c")
+        XCTAssertEqual(textView.string, "func helloWorld() {\n\tprint(\"Hello World!\")\n}")
+
+        // Replace contents
+        textView.replaceCharacters(in: textView.documentRange, with: "")
+        textView.insertText("func helloWorld() {\n\tprint(\"Hello World!\")\n}")
+        XCTAssertEqual(textView.string, "func helloWorld() {\n\tprint(\"Hello World!\")\n}")
+    }
 }

Tests/CodeEditSourceEditorTests/Highlighting/StyledRangeStoreTests.swift

@@ -36,6 +36,20 @@ final class StyledRangeStoreTests: XCTestCase {
         XCTAssertEqual(store.count, 1, "Failed to coalesce")
     }
 
+    func test_storageRemoveSingleCharacterFromEnd() {
+        let store = StyledRangeStore(documentLength: 10)
+        store.set( // Test that we can delete a character associated with a single syntax run too
+            runs: [
+                .empty(length: 8),
+                .init(length: 1, modifiers: [.abstract]),
+                .init(length: 1, modifiers: [.declaration])],
+            for: 0..<10
+        )
+        store.storageUpdated(replacedCharactersIn: 9..<10, withCount: 0)
+        XCTAssertEqual(store.length, 9, "Failed to remove correct range")
+        XCTAssertEqual(store.count, 2)
+    }
+
     func test_storageRemoveFromBeginning() {
         let store = StyledRangeStore(documentLength: 100)
         store.storageUpdated(replacedCharactersIn: 0..<15, withCount: 0)