fix: prevent thumbnail grid launch crash from column and data drift

2 files changed, 37 insertions, 18 deletions

diff --git a/Sora/Views/Shared/ThumbnailGridView.swift b/Sora/Views/Shared/ThumbnailGridView.swift
index a7130c2..ec8cd10 100644
--- a/Sora/Views/Shared/ThumbnailGridView.swift
+++ b/Sora/Views/Shared/ThumbnailGridView.swift
@@ -8,12 +8,27 @@ struct ThumbnailGridView<Item: Hashable & Identifiable, Content: View>: View {
   let columnsData: [[Item]]
   let content: (Item) -> Content
 
+  private var resolvedColumnCount: Int {
+    max(columnCount, 1)
+  }
+
+  private var resolvedColumnsData: [[Item]] {
+    let clippedColumnsData = Array(columnsData.prefix(resolvedColumnCount))
+    let missingColumnCount = resolvedColumnCount - clippedColumnsData.count
+
+    if missingColumnCount <= 0 {
+      return clippedColumnsData
+    }
+
+    return clippedColumnsData + Array(repeating: [], count: missingColumnCount)
+  }
+
   var body: some View {
     if useAlternativeGrid {
       HStack(alignment: .top) {
-        ForEach(0..<columnCount, id: \.self) { columnIndex in
+        ForEach(Array(resolvedColumnsData.enumerated()), id: \.offset) { _, columnItems in
           LazyVStack {
-            ForEach(columnsData[columnIndex], id: \.id) { item in
+            ForEach(columnItems, id: \.id) { item in
               content(item)
                 .id(item.id)
             }
@@ -32,7 +47,7 @@ struct ThumbnailGridView<Item: Hashable & Identifiable, Content: View>: View {
         content(item)
           .id(item.id)
       }
-      .gridStyle(columns: columnCount)
+      .gridStyle(columns: resolvedColumnCount)
       .transaction { $0.animation = nil }
       #if os(macOS)
         .padding(8)
diff --git a/SoraTests/ViewDerivedDataTests.swift b/SoraTests/ViewDerivedDataTests.swift
index d8760e7..bc3a998 100644
--- a/SoraTests/ViewDerivedDataTests.swift
+++ b/SoraTests/ViewDerivedDataTests.swift
@@ -267,28 +267,32 @@ final class ViewDerivedDataTests: XCTestCase {
     )
   }
 
-  private func referenceCount(for symbol: String, in source: String) -> Int {
-    let totalMatches = tokenCount(
-      matching: #"\b\#(symbol)\b"#,
-      in: source
+  func testThumbnailGridViewAvoidsDirectColumnArrayIndexing() throws {
+    let source = try loadSource(at: "Sora/Views/Shared/ThumbnailGridView.swift")
+    let normalizedSource = strippingCommentsAndStrings(from: source)
+    let directColumnIndexingCount = tokenCount(
+      matching: #"\bcolumnsData\s*\[\s*columnIndex\s*\]"#,
+      in: normalizedSource
     )
-    let declarationMatches = tokenCount(
-      matching: #"\b(?:var|let)\s+\#(symbol)\b"#,
-      in: source
+
+    // swiftlint:disable:next prefer_nimble
+    XCTAssertEqual(
+      directColumnIndexingCount,
+      0,
+      "Thumbnail grid should avoid direct column indexing that can crash when column and data counts drift."
     )
+  }
+
+  private func referenceCount(for symbol: String, in source: String) -> Int {
+    let totalMatches = tokenCount(matching: #"\b\#(symbol)\b"#, in: source)
+    let declarationMatches = tokenCount(matching: #"\b(?:var|let)\s+\#(symbol)\b"#, in: source)
 
     return max(0, totalMatches - declarationMatches)
   }
 
   private func invocationCount(forFunction name: String, in source: String) -> Int {
-    let totalMatches = tokenCount(
-      matching: #"\b\#(name)\s*\("#,
-      in: source
-    )
-    let declarationMatches = tokenCount(
-      matching: #"\bfunc\s+\#(name)\s*\("#,
-      in: source
-    )
+    let totalMatches = tokenCount(matching: #"\b\#(name)\s*\("#, in: source)
+    let declarationMatches = tokenCount(matching: #"\bfunc\s+\#(name)\s*\("#, in: source)
 
     return max(0, totalMatches - declarationMatches)
   }