Validate command output display mutations

Sources/ReviewChatLogUI/Detail/ReviewMonitorCommandOutputDisplayDocument.swift

@@ -794,69 +794,148 @@ enum ReviewMonitorCommandOutputDisplayDocument {
     ) -> ReviewMonitorLog.Change {
         switch change {
         case .append(let append):
-            guard
-                let mappedRange = mappedChangeRange(
-                    append.range,
-                    blockID: append.blockID,
-                    sourceBlocks: sourceBlocks,
-                    displayBlocks: displayBlocks
+            if let panelMutation = mappedCommandPanelMutation(
+                sourceRange: append.range,
+                blockID: append.blockID,
+                sourceBlocks: sourceBlocks,
+                displayBlocks: displayBlocks,
+                previousDisplay: previousDisplay,
+                displayText: displayText
+            ),
+                let validatedMutation = validatedChange(
+                    panelMutation,
+                    previousDisplay: previousDisplay,
+                    displayText: displayText
                 )
-            else {
-                if let panelMutation = mappedCommandPanelMutation(
-                    sourceRange: append.range,
-                    blockID: append.blockID,
-                    sourceBlocks: sourceBlocks,
-                    displayBlocks: displayBlocks,
+            {
+                return validatedMutation
+            }
+            if let displayAppend = mappedDisplayAppend(
+                previousDisplay: previousDisplay,
+                displayText: displayText,
+                displayBlocks: displayBlocks
+            ),
+                let validatedMutation = validatedChange(
+                    .append(displayAppend),
                     previousDisplay: previousDisplay,
                     displayText: displayText
-                ) {
-                    return panelMutation
-                }
-                return .reload
+                )
+            {
+                return validatedMutation
             }
-            return .append(
-                .init(
-                    kind: append.kind,
-                    blockID: append.blockID,
-                    range: mappedRange,
-                    text: append.text,
-                    textUTF16Length: append.textUTF16Length,
-                    animationSpans: append.animationSpans
-                ))
+            return .reload
         case .replace(let replacement):
-            guard
-                let mappedRange = mappedChangeRange(
-                    replacement.range,
-                    blockID: replacement.blockID,
-                    sourceBlocks: sourceBlocks,
-                    displayBlocks: displayBlocks
+            if let mappedReplacement = mappedBlockReplacement(
+                replacement,
+                sourceBlocks: sourceBlocks,
+                displayBlocks: displayBlocks,
+                previousDisplay: previousDisplay,
+                displayText: displayText
+            ),
+                let validatedMutation = validatedChange(
+                    .replace(mappedReplacement),
+                    previousDisplay: previousDisplay,
+                    displayText: displayText
                 )
-            else {
-                if let panelMutation = mappedCommandPanelMutation(
+            {
+                return validatedMutation
+            }
+            if let panelMutation = mappedCommandPanelMutation(
                     sourceRange: replacement.range,
                     blockID: replacement.blockID,
                     sourceBlocks: sourceBlocks,
                     displayBlocks: displayBlocks,
                     previousDisplay: previousDisplay,
                     displayText: displayText
-                ) {
-                    return panelMutation
-                }
-                return .reload
+            ),
+                let validatedMutation = validatedChange(
+                    panelMutation,
+                    previousDisplay: previousDisplay,
+                    displayText: displayText
+                )
+            {
+                return validatedMutation
             }
-            return .replace(
-                .init(
-                    kind: replacement.kind,
-                    blockID: replacement.blockID,
-                    range: mappedRange,
-                    text: replacement.text,
-                    textUTF16Length: replacement.textUTF16Length
-                ))
+            return .reload
         case .reload:
             return .reload
         }
     }
 
+    private static func mappedDisplayAppend(
+        previousDisplay: ReviewMonitorLog.Document?,
+        displayText: String,
+        displayBlocks: [ReviewMonitorLog.Block]
+    ) -> ReviewMonitorLog.Append? {
+        guard let previousDisplay else {
+            return nil
+        }
+
+        let displayString = displayText as NSString
+        let previousLength = previousDisplay.textUTF16Length
+        guard previousLength < displayString.length,
+            displayString.substring(with: NSRange(location: 0, length: previousLength)) == previousDisplay.text
+        else {
+            return nil
+        }
+
+        let suffixRange = NSRange(location: previousLength, length: displayString.length - previousLength)
+        let suffix = displayString.substring(with: suffixRange)
+        let block = displayBlocks.first {
+            NSIntersectionRange($0.range, suffixRange).length > 0
+        }
+        return .init(
+            kind: block?.kind ?? .event,
+            blockID: block?.id ?? ReviewMonitorLog.BlockID("commandOutputDisplayAppend"),
+            range: suffixRange,
+            text: suffix,
+            textUTF16Length: suffixRange.length,
+            animationSpans: displayBlocks.flatMap { block in
+                let intersection = NSIntersectionRange(block.range, suffixRange)
+                guard intersection.length > 0 else {
+                    return [] as [ReviewMonitorLog.AnimationSpan]
+                }
+                return ReviewMonitorLog.Append.animationSpans(
+                    forKind: block.kind,
+                    absoluteRange: intersection,
+                    appendBaseLocation: previousLength
+                )
+            }
+        )
+    }
+
+    private static func mappedBlockReplacement(
+        _ replacement: ReviewMonitorLog.Replacement,
+        sourceBlocks: [ReviewMonitorLog.Block],
+        displayBlocks: [ReviewMonitorLog.Block],
+        previousDisplay: ReviewMonitorLog.Document?,
+        displayText: String
+    ) -> ReviewMonitorLog.Replacement? {
+        guard let previousDisplay,
+            let sourceBlock = sourceBlocks.first(where: { $0.id == replacement.blockID }),
+            sourceBlock.kind != .command,
+            sourceBlock.kind != .commandOutput,
+            let displayBlock = displayBlocks.first(where: { $0.id == replacement.blockID }),
+            let previousDisplayBlock = previousDisplay.blocks.first(where: { $0.id == replacement.blockID })
+        else {
+            return nil
+        }
+
+        guard rangeIsValid(displayBlock.range, in: displayText),
+            rangeIsValid(previousDisplayBlock.range, in: previousDisplay.text)
+        else {
+            return nil
+        }
+        let replacementText = (displayText as NSString).substring(with: displayBlock.range)
+        return .init(
+            kind: displayBlock.kind,
+            blockID: displayBlock.id,
+            range: previousDisplayBlock.range,
+            text: replacementText,
+            textUTF16Length: (replacementText as NSString).length
+        )
+    }
+
     private static func mappedCommandPanelMutation(
         sourceRange: NSRange,
         blockID: ReviewMonitorLog.BlockID,
@@ -907,6 +986,37 @@ enum ReviewMonitorCommandOutputDisplayDocument {
         return .append(append)
     }
 
+    private static func validatedChange(
+        _ change: ReviewMonitorLog.Change,
+        previousDisplay: ReviewMonitorLog.Document?,
+        displayText: String
+    ) -> ReviewMonitorLog.Change? {
+        guard let previousDisplay else {
+            return nil
+        }
+        switch change {
+        case .append(let append):
+            guard append.textUTF16Length == (append.text as NSString).length,
+                append.range.location == previousDisplay.textUTF16Length,
+                append.range.length == append.textUTF16Length,
+                previousDisplay.text + append.text == displayText
+            else {
+                return nil
+            }
+            return change
+        case .replace(let replacement):
+            guard replacement.textUTF16Length == (replacement.text as NSString).length,
+                rangeIsValid(replacement.range, in: previousDisplay.text),
+                replacingText(in: previousDisplay.text, range: replacement.range, with: replacement.text) == displayText
+            else {
+                return nil
+            }
+            return change
+        case .reload:
+            return change
+        }
+    }
+
     private static func mappedNewCommandPanelAppend(
         displayBlock: ReviewMonitorLog.Block,
         displayText: String,
@@ -958,25 +1068,25 @@ enum ReviewMonitorCommandOutputDisplayDocument {
         }
     }
 
-    private static func mappedChangeRange(
-        _ range: NSRange,
-        blockID: ReviewMonitorLog.BlockID,
-        sourceBlocks: [ReviewMonitorLog.Block],
-        displayBlocks: [ReviewMonitorLog.Block]
-    ) -> NSRange? {
-        guard let sourceBlock = sourceBlocks.first(where: { $0.id == blockID }),
-            sourceBlock.kind != .command,
-            sourceBlock.kind != .commandOutput,
-            let displayBlock = displayBlocks.first(where: { $0.id == blockID }),
-            NSMaxRange(range) <= NSMaxRange(sourceBlock.range)
+    private static func rangeIsValid(_ range: NSRange, in text: String) -> Bool {
+        let length = (text as NSString).length
+        return range.location >= 0 && range.length >= 0 && NSMaxRange(range) <= length
+    }
+
+    private static func replacingText(in text: String, range: NSRange, with replacement: String) -> String {
+        let string = text as NSString
+        guard range.location >= 0,
+            range.length >= 0,
+            NSMaxRange(range) <= string.length
         else {
-            return nil
+            return text
         }
-        let mappedRange = map(range, from: sourceBlock.range, to: displayBlock.range)
-        guard NSMaxRange(mappedRange) <= NSMaxRange(displayBlock.range) else {
-            return nil
-        }
-        return mappedRange
+        let prefix = string.substring(with: NSRange(location: 0, length: range.location))
+        let suffixLocation = NSMaxRange(range)
+        let suffix = string.substring(
+            with: NSRange(location: suffixLocation, length: string.length - suffixLocation)
+        )
+        return prefix + replacement + suffix
     }
 }
 

Sources/ReviewChatLogUI/Detail/ReviewMonitorLogDocumentView.swift

@@ -711,7 +711,7 @@ final class ReviewMonitorLogDocumentView: NSView, NSUserInterfaceValidations,
         }
 
         if block.kind.requiresMarkdownPresentationInvalidationOnAppend {
-            return block.range
+            return NSUnionRange(block.range, append.range)
         }
         return append.range
     }
@@ -2726,6 +2726,18 @@ final class ReviewMonitorLogDocumentView: NSView, NSUserInterfaceValidations,
             return hitTest(NSPoint(x: rect.midX, y: rect.midY)) === self
         }
 
+        func fontPointSizeForFirstOccurrenceForTesting(_ text: String) -> CGFloat? {
+            layoutTextViewport(force: true)
+            let range = (textStorage.string as NSString).range(of: text)
+            guard range.location != NSNotFound,
+                range.location < textStorage.length,
+                let font = textStorage.attribute(.font, at: range.location, effectiveRange: nil) as? NSFont
+            else {
+                return nil
+            }
+            return font.pointSize
+        }
+
         func toggleFirstCommandOutputPanelForTesting() {
             layoutTextViewport(force: true)
             guard let blockID = currentCommandOutputPanels.first?.blockID else {

Sources/ReviewChatLogUI/Detail/ReviewMonitorLogScrollView.swift

@@ -344,21 +344,34 @@ final class ReviewMonitorLogScrollView: NSScrollView {
         guard append.text.isEmpty == false else {
             return false
         }
-        let appendEnd = displayedUTF16Length + append.textUTF16Length
-        return append.textUTF16Length > 0 &&
-            append.range.location >= displayedUTF16Length &&
-            NSMaxRange(append.range) <= appendEnd &&
-            document.textUTF16Length == displayedUTF16Length + append.textUTF16Length
+        let expectedRange = NSRange(location: displayedUTF16Length, length: append.textUTF16Length)
+        guard append.textUTF16Length == (append.text as NSString).length,
+            append.range == expectedRange,
+            document.textUTF16Length == displayedUTF16Length + append.textUTF16Length,
+            displayedText + append.text == document.text
+        else {
+            assertionFailure("Log append change is not synchronized with the display document.")
+            return false
+        }
+        return true
     }
 
     private func canApplyReplacement(
         _ replacement: ReviewMonitorLog.Replacement,
         to document: ReviewMonitorLog.Document
     ) -> Bool {
-        replacement.textUTF16Length >= 0 &&
-            replacement.range.location >= 0 &&
-            NSMaxRange(replacement.range) <= displayedUTF16Length &&
-        document.textUTF16Length == displayedUTF16Length - replacement.range.length + replacement.textUTF16Length
+        guard replacement.textUTF16Length == (replacement.text as NSString).length,
+            replacement.range.location >= 0,
+            replacement.range.length >= 0,
+            NSMaxRange(replacement.range) <= displayedUTF16Length,
+            document.textUTF16Length == displayedUTF16Length - replacement.range.length + replacement.textUTF16Length,
+            let replacementResult = replacingDisplayedText(in: replacement.range, with: replacement.text),
+            replacementResult == document.text
+        else {
+            assertionFailure("Log replacement change is not synchronized with the display document.")
+            return false
+        }
+        return true
     }
 
     private func canApplyFallbackAppend(_ suffix: String, to document: ReviewMonitorLog.Document) -> Bool {
@@ -883,6 +896,18 @@ final class ReviewMonitorLogScrollView: NSScrollView {
         displayedText = mutable as String
     }
 
+    private func replacingDisplayedText(in range: NSRange, with text: String) -> String? {
+        guard range.location >= 0,
+            range.length >= 0,
+            NSMaxRange(range) <= displayedUTF16Length
+        else {
+            return nil
+        }
+        let mutable = NSMutableString(string: displayedText)
+        mutable.replaceCharacters(in: range, with: text)
+        return mutable as String
+    }
+
     private func invalidateDocumentLayout() {
         if syncDocumentFrameToTextLayout() {
             logDocumentView.invalidateIntrinsicContentSize()
@@ -1536,6 +1561,10 @@ extension ReviewMonitorLogScrollView {
         logDocumentView.hitTestTargetsDocumentViewForFirstOccurrenceForTesting(text)
     }
 
+    func fontPointSizeForFirstLogOccurrenceForTesting(_ text: String) -> CGFloat? {
+        logDocumentView.fontPointSizeForFirstOccurrenceForTesting(text)
+    }
+
     func toggleFirstCommandOutputPanelForTesting() {
         logDocumentView.toggleFirstCommandOutputPanelForTesting()
     }

Sources/ReviewChatLogUI/ReviewMonitorCodexChatLogTarget.swift

@@ -514,6 +514,10 @@ package final class ReviewMonitorCodexChatLogTarget {
             logScrollView.hitTestTargetsDocumentViewForFirstLogOccurrenceForTesting(text)
         }
 
+        func fontPointSizeForFirstLogOccurrenceForTesting(_ text: String) -> CGFloat? {
+            logScrollView.fontPointSizeForFirstLogOccurrenceForTesting(text)
+        }
+
         func toggleFirstCommandOutputPanelForTesting() {
             logScrollView.toggleFirstCommandOutputPanelForTesting()
         }

Sources/ReviewUI/Detail/ReviewMonitorTransportViewController.swift

@@ -388,6 +388,10 @@ final class ReviewMonitorTransportViewController: NSViewController {
             chatLogTarget.hitTestTargetsDocumentViewForFirstLogOccurrenceForTesting(text)
         }
 
+        func logFontPointSizeForFirstOccurrenceForTesting(_ text: String) -> CGFloat? {
+            chatLogTarget.fontPointSizeForFirstLogOccurrenceForTesting(text)
+        }
+
         func toggleFirstLogCommandOutputPanelForTesting() {
             chatLogTarget.toggleFirstCommandOutputPanelForTesting()
         }