fix: detect RAR block-payload differences in Compare tab

Thread IHexDataSource through IFileCompareService.Compare /
FileCompareService.Compare so the parent app can pass the left/right
MemoryMappedDataSource into FileComparer. FileCompareViewModel forwards
both sources during RefreshComparison and calls the new
HasBlockDifferences in ApplyNodeHighlighting so file/service blocks
whose data payloads differ are now flagged [DIFF] in the structure
tree. UpdateStatus checks LeftDiffRanges / RightDiffRanges and reports
"Byte-level differences detected in current hex view..." when the
structural compare returns zero diffs but the byte-level hex diff has
non-empty ranges, so the status bar can no longer disagree with the
red highlights painted in the hex view.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: NeWbY100

CHANGELOG.md

@@ -4,6 +4,29 @@ All notable changes to ReScene.NET are documented here.
 Releases follow [SemVer](https://semver.org/) and this file follows
 [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [1.2.4] — 2026-05-10
+
+### Fixed
+
+- Compare tab no longer reports two RAR files as identical when only
+  their block payload bytes differ. `FileComparer.CompareDetailedBlocks`
+  now byte-compares each block's data region (`StartOffset + HeaderSize`
+  through `+ DataSize`) in 64 KB chunks when both sides supply an
+  `IHexDataSource`, surfacing a `Block Data` property difference and
+  marking the affected file/service block as `[DIFF]` in the structure
+  tree. Previously the comparator only inspected parsed RAR header
+  fields, so two archives with identical metadata (filename, packed
+  size, file CRC32, timestamp) but different compressed payloads — the
+  exact case produced when reconstructing — slipped through as
+  "identical."
+- The status bar can no longer disagree with the hex-view byte diff:
+  when the structural compare finds zero differences but the byte-level
+  hex diff reports differing ranges, the status now reads "Byte-level
+  differences detected in current hex view but no structural
+  differences found." instead of "Files are identical."
+
+[1.2.4]: https://github.com/NeWbY100/ReScene.NET/releases/tag/v1.2.4
+
 ## [1.2.3] — 2026-05-08
 
 ### Added

ReScene.Lib

@@ -1,4 +1,5 @@
 using ReScene.Core.Comparison;
+using ReScene.Hex;
 using ReScene.RAR;
 using ReScene.SRS;
 
@@ -42,5 +43,6 @@ public class FileCompareService : IFileCompareService
 
     /// <inheritdoc />
     public CompareResult Compare(object? leftData, object? rightData,
-        List<RARDetailedBlock>? leftBlocks = null, List<RARDetailedBlock>? rightBlocks = null) => FileComparer.Compare(leftData, rightData, leftBlocks, rightBlocks);
+        List<RARDetailedBlock>? leftBlocks = null, List<RARDetailedBlock>? rightBlocks = null,
+        IHexDataSource? leftSource = null, IHexDataSource? rightSource = null) => FileComparer.Compare(leftData, rightData, leftBlocks, rightBlocks, leftSource, rightSource);
 }

ReScene.NET/Services/FileCompareService.cs

@@ -1,4 +1,5 @@
 using ReScene.Core.Comparison;
+using ReScene.Hex;
 using ReScene.RAR;
 
 namespace ReScene.NET.Services;
@@ -45,9 +46,16 @@ public interface IFileCompareService
     /// <param name="rightBlocks">
     /// Optional detailed RAR blocks for the right file.
     /// </param>
+    /// <param name="leftSource">
+    /// Optional byte-level data source for the left file, used to compare block payloads.
+    /// </param>
+    /// <param name="rightSource">
+    /// Optional byte-level data source for the right file, used to compare block payloads.
+    /// </param>
     /// <returns>
     /// A <see cref="CompareResult"/> describing all differences found.
     /// </returns>
     public CompareResult Compare(object? leftData, object? rightData,
-        List<RARDetailedBlock>? leftBlocks = null, List<RARDetailedBlock>? rightBlocks = null);
+        List<RARDetailedBlock>? leftBlocks = null, List<RARDetailedBlock>? rightBlocks = null,
+        IHexDataSource? leftSource = null, IHexDataSource? rightSource = null);
 }

ReScene.NET/Services/IFileCompareService.cs

@@ -432,7 +432,8 @@ private void RefreshComparison()
         if (_leftData is not null && _rightData is not null)
         {
             _compareResult = _compareService.Compare(_leftData, _rightData,
-                _leftDetailedBlocks, _rightDetailedBlocks);
+                _leftDetailedBlocks, _rightDetailedBlocks,
+                _leftFileSource, _rightFileSource);
             ApplyComparisonHighlighting();
             UpdateStatus();
         }
@@ -466,10 +467,21 @@ private void UpdateStatus()
 
         if (totalDiffs == 0)
         {
-            StatusMessage = "Files are identical.";
-            DiffSummary = "No differences found - files are identical.";
-            HasDiffSummary = true;
-            FilesIdentical = true;
+            int byteDiffRanges = (LeftDiffRanges?.Count ?? 0) + (RightDiffRanges?.Count ?? 0);
+            if (byteDiffRanges > 0)
+            {
+                StatusMessage = "Byte-level differences detected in current hex view but no structural differences found.";
+                DiffSummary = "Byte-level differences detected in current hex view.";
+                HasDiffSummary = true;
+                FilesIdentical = false;
+            }
+            else
+            {
+                StatusMessage = "Files are identical.";
+                DiffSummary = "No differences found - files are identical.";
+                HasDiffSummary = true;
+                FilesIdentical = true;
+            }
         }
         else
         {
@@ -1199,7 +1211,8 @@ private void ApplyNodeHighlighting(TreeNodeViewModel node, HashSet<string> remov
                 {
                     RARDetailedBlock? otherBlock = otherBlocks.FirstOrDefault(b =>
                         b.BlockType == block.BlockType && b.ItemName == block.ItemName);
-                    if (otherBlock is not null && FileComparer.HasFieldDifferences(block, otherBlock))
+                    if (otherBlock is not null
+                        && FileComparer.HasBlockDifferences(block, otherBlock, _leftFileSource, _rightFileSource))
                     {
                         node.Text = $"{GetBaseNodeText(node.Text)} [DIFF]";
                         node.IsDifferent = true;