fix candidate full button

app/src/main/java/com/kazumaproject/markdownhelperkeyboard/ime_service/IMEService.kt

@@ -222,6 +222,7 @@ import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateS
 import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateQueryModeResolver
 import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateRefreshCoordinator
 import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateRefreshRequest
+import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateRefreshTransitionPolicy
 import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateRequestToken
 import com.kazumaproject.markdownhelperkeyboard.ime_service.candidate.CandidateRequestTracker
 import com.kazumaproject.markdownhelperkeyboard.ime_service.clipboard.ClipboardUtil
@@ -14645,10 +14646,11 @@ class IMEService : InputMethodService(), LifecycleOwner, InputConnection,
                     prevFlag,
                     currentFlag,
                 )
-                if (
-                    prevFlag == CandidateShowFlag.Idle &&
-                    currentFlag == CandidateShowFlag.Updating &&
-                    insertString.isNotEmpty()
+                if (CandidateRefreshTransitionPolicy.shouldEnterActiveCandidatePhase(
+                        previousFlag = prevFlag,
+                        currentFlag = currentFlag,
+                        input = insertString,
+                    )
                 ) {
                     clearZeroQueryAllState(refresh = false)
                     shortcutToolbarHiddenForCandidates = true
@@ -14798,7 +14800,10 @@ class IMEService : InputMethodService(), LifecycleOwner, InputConnection,
                         }
                     }
                 }
-                prevFlag = currentFlag
+                prevFlag = CandidateRefreshTransitionPolicy.nextUiPreviousFlag(
+                    currentFlag = currentFlag,
+                    input = insertString,
+                )
             }
         }
 

app/src/main/java/com/kazumaproject/markdownhelperkeyboard/ime_service/candidate/CandidateRefreshTransitionPolicy.kt

@@ -0,0 +1,34 @@
+package com.kazumaproject.markdownhelperkeyboard.ime_service.candidate
+
+import com.kazumaproject.markdownhelperkeyboard.ime_service.models.CandidateShowFlag
+
+/**
+ * Keeps non-user candidate refreshes from changing the visible conversion phase.
+ *
+ * Dictionary loading can publish an Updating request while the composing input is empty. That
+ * request refreshes data, but it must not consume the Idle -> Updating transition used by the
+ * candidate-strip UI to show the full-candidate toggle.
+ */
+internal object CandidateRefreshTransitionPolicy {
+
+    fun shouldEnterActiveCandidatePhase(
+        previousFlag: CandidateShowFlag?,
+        currentFlag: CandidateShowFlag,
+        input: String,
+    ): Boolean {
+        return previousFlag == CandidateShowFlag.Idle &&
+            currentFlag == CandidateShowFlag.Updating &&
+            input.isNotEmpty()
+    }
+
+    fun nextUiPreviousFlag(
+        currentFlag: CandidateShowFlag,
+        input: String,
+    ): CandidateShowFlag {
+        return if (currentFlag == CandidateShowFlag.Updating && input.isEmpty()) {
+            CandidateShowFlag.Idle
+        } else {
+            currentFlag
+        }
+    }
+}

app/src/test/java/com/kazumaproject/markdownhelperkeyboard/ime_service/candidate/CandidateRefreshCoordinatorTest.kt

@@ -14,6 +14,34 @@ import org.junit.Test
 
 class CandidateRefreshCoordinatorTest {
 
+    @Test
+    fun emptyUpdatingDoesNotConsumeTheNextActiveCandidateTransition() {
+        val afterDictionaryRefresh = CandidateRefreshTransitionPolicy.nextUiPreviousFlag(
+            currentFlag = CandidateShowFlag.Updating,
+            input = "",
+        )
+
+        assertEquals(CandidateShowFlag.Idle, afterDictionaryRefresh)
+        assertTrue(
+            CandidateRefreshTransitionPolicy.shouldEnterActiveCandidatePhase(
+                previousFlag = afterDictionaryRefresh,
+                currentFlag = CandidateShowFlag.Updating,
+                input = "かな",
+            )
+        )
+    }
+
+    @Test
+    fun nonEmptyUpdatingRemainsTheActiveCandidatePhase() {
+        assertEquals(
+            CandidateShowFlag.Updating,
+            CandidateRefreshTransitionPolicy.nextUiPreviousFlag(
+                currentFlag = CandidateShowFlag.Updating,
+                input = "かな",
+            )
+        )
+    }
+
     @Test
     fun repeatedUpdatingRequestsRemainDistinctAndCarryTheirInputSnapshot() {
         val coordinator = CandidateRefreshCoordinator()