From 48c267f47e23387a0f5a33cd8814f0ba6bba9a6d Mon Sep 17 00:00:00 2001
From: ensan-hcl <ensan.hcl.dev@gmail.com>
Date: Tue, 15 Jul 2025 14:05:44 -0700
Subject: [PATCH] fix: itta-then-delete crash

---
 .../Core/SuffixReplacementProcessing.swift    |  8 ++++---
 .../DictionaryManagement/DicdataStore.swift   |  4 ++--
 .../ConverterTests/ConverterTests.swift       | 24 +++++++++++++++++++
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/Sources/KanaKanjiConverterModule/ConversionAlgorithms/Core/SuffixReplacementProcessing.swift b/Sources/KanaKanjiConverterModule/ConversionAlgorithms/Core/SuffixReplacementProcessing.swift
index 24e29ed..e62078c 100644
--- a/Sources/KanaKanjiConverterModule/ConversionAlgorithms/Core/SuffixReplacementProcessing.swift
+++ b/Sources/KanaKanjiConverterModule/ConversionAlgorithms/Core/SuffixReplacementProcessing.swift
@@ -58,12 +58,12 @@ extension Kana2Kanji {
         } else {
             // (2)
             let rawNodes = latticeIndices.map { index in
-                let inputRange: (startIndex: Int, endIndexRange: Range<Int>?)? = if let iIndex = index.inputIndex {
+                let inputRange: (startIndex: Int, endIndexRange: Range<Int>?)? = if let iIndex = index.inputIndex, max(commonInputCount, iIndex) < inputCount {
                     (iIndex, max(commonInputCount, iIndex) ..< inputCount)
                 } else {
                     nil
                 }
-                let surfaceRange: (startIndex: Int, endIndexRange: Range<Int>?)? = if let sIndex = index.surfaceIndex {
+                let surfaceRange: (startIndex: Int, endIndexRange: Range<Int>?)? = if let sIndex = index.surfaceIndex, max(commonSurfaceCount, sIndex) < surfaceCount {
                     (sIndex, max(commonSurfaceCount, sIndex) ..< surfaceCount)
                 } else {
                     nil
@@ -92,7 +92,9 @@ extension Kana2Kanji {
                     }
                     // 変換した文字数
                     let nextIndex = indexMap.dualIndex(for: node.range.endIndex)
-                    self.updateNextNodes(with: node, nextNodes: addedNodes[index: nextIndex], nBest: N_best)
+                    if nextIndex != .bothIndex(inputIndex: inputCount, surfaceIndex: surfaceCount) {
+                        self.updateNextNodes(with: node, nextNodes: addedNodes[index: nextIndex], nBest: N_best)
+                    }
                 }
             }
             lattice.merge(addedNodes)
diff --git a/Sources/KanaKanjiConverterModule/DictionaryManagement/DicdataStore.swift b/Sources/KanaKanjiConverterModule/DictionaryManagement/DicdataStore.swift
index e2b74f4..f72db8c 100644
--- a/Sources/KanaKanjiConverterModule/DictionaryManagement/DicdataStore.swift
+++ b/Sources/KanaKanjiConverterModule/DictionaryManagement/DicdataStore.swift
@@ -488,7 +488,7 @@ public final class DicdataStore {
                 inputRange.startIndex + self.maxlength
             )
             if inputRange.startIndex > toInputIndexLeft || toInputIndexLeft >= toInputIndexRight {
-                debug(#function, "index is wrong")
+                debug(#function, "index is wrong", inputRange)
                 return []
             }
             inputProcessRange = .init(leftIndex: inputRange.startIndex, rightIndexRange: toInputIndexLeft ..< toInputIndexRight)
@@ -504,7 +504,7 @@ public final class DicdataStore {
                 surfaceRange.startIndex + self.maxlength
             )
             if surfaceRange.startIndex > toSurfaceIndexLeft || toSurfaceIndexLeft >= toSurfaceIndexRight {
-                debug(#function, "index is wrong")
+                debug(#function, "index is wrong", surfaceRange)
                 return []
             }
             surfaceProcessRange = .init(leftIndex: surfaceRange.startIndex, rightIndexRange: toSurfaceIndexLeft ..< toSurfaceIndexRight)
diff --git a/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ConverterTests/ConverterTests.swift b/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ConverterTests/ConverterTests.swift
index 011ed86..fab5abe 100644
--- a/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ConverterTests/ConverterTests.swift
+++ b/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ConverterTests/ConverterTests.swift
@@ -132,6 +132,30 @@ final class ConverterTests: XCTestCase {
             }
     }
 
+    // memo: このケースでfatalErrorが発生する不具合が生じることがあった
+    func testIttaAndThenDelete() async throws {
+        let converter = await KanaKanjiConverter()
+        var c = ComposingText()
+        let text = "itta"
+        // 許容される変換結果
+        let possibles = [
+            "いった",
+            "行った",
+            "言った"
+        ]
+        for char in text {
+            c.insertAtCursorPosition(String(char), inputStyle: .roman2kana)
+            let results = await converter.requestCandidates(c, options: requestOptions())
+            if c.input.count == text.count {
+                XCTAssertTrue(possibles.contains(results.mainResults.first!.text))
+            }
+        }
+        // 1文字削除
+        c.deleteBackwardFromCursorPosition(count: 1)
+        let results = await converter.requestCandidates(c, options: requestOptions())
+        XCTAssertTrue(results.mainResults.contains { $0.text == "言っ" })
+    }
+
     // 1文字ずつ入力するが、時折削除を行う
     // memo: 内部実装としてはdeleted_last_nのテストを意図している
     func testGradualConversionWithDelete() async throws {