From 0d66107743a7952053471eea9f6b9def5c11a629 Mon Sep 17 00:00:00 2001
From: Hyungi Ahn <hyungiahn@Hyungiui-MacBookPro.local>
Date: Tue, 28 Apr 2026 13:14:52 +0900
Subject: [PATCH] =?UTF-8?q?fix(study):=20=ED=9A=8C=EC=B0=A8=20=EB=B3=80?=
 =?UTF-8?q?=EA=B2=BD=20race=20=EC=A0=9C=EA=B1=B0=20=E2=80=94=20$effect=20?=
 =?UTF-8?q?=E2=86=92=20=EB=AA=85=EC=8B=9C=EC=A0=81=20onchange=20=ED=95=B8?=
 =?UTF-8?q?=EB=93=A4=EB=9F=AC?=
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$effect 가 examRounds fetch 전 첫 실행되며 f_qnum=1 로 reset 하는 race 가
이전 fix(lastExamRound sync) 만으로 완전히 막히지 않음. effect 자체를
제거하고 select onchange + applyNewRound 에서 명시 호출하는 onRoundChange()
로 변경. examRounds 미적재 시 (length=0) 는 skip — onMount fallback 이 처리.

이제 흐름:
- 진입 (sessionStorage prefill 만 있음) → onMount await fetch 후 fallback
  으로 next_question_number 적용
- dropdown 으로 회차 변경 → onchange={onRoundChange}
- 새 회차 입력 → applyNewRound() 안에서 직접 f_qnum=1
- examRounds 변경 (저장 후 refreshExamRounds) → 어떤 자동 reset 도 발생 안 함
---
 .../topics/[id]/questions/new/+page.svelte    | 32 +++++++++++--------
 1 file changed, 19 insertions(+), 13 deletions(-)

diff --git a/frontend/src/routes/study/topics/[id]/questions/new/+page.svelte b/frontend/src/routes/study/topics/[id]/questions/new/+page.svelte
index 9566df2..dec4c7b 100644
--- a/frontend/src/routes/study/topics/[id]/questions/new/+page.svelte
+++ b/frontend/src/routes/study/topics/[id]/questions/new/+page.svelte
@@ -158,21 +158,27 @@
     return Array.from(set);
   });
 
-  // 회차 변경 감지 → 문항 번호 자동 reset
+  // PR-7 fix: 회차 변경은 명시적 onchange 핸들러로 처리 (이전 $effect 패턴은
+  // examRounds fetch 전에 첫 실행되며 f_qnum=1 로 reset 하는 race 발생).
+  // 사용자가 dropdown 으로 회차를 바꿀 때 + applyNewRound() 에서만 호출.
   let lastExamRound = $state('');
-  $effect(() => {
-    if (f_exam_round && f_exam_round !== lastExamRound) {
-      // 기존 회차면 next_question_number, 아니면 1
-      const found = examRounds.find((r) => r.exam_round === f_exam_round);
-      if (found && found.next_question_number) {
-        f_qnum = found.next_question_number;
-      } else if (!found) {
-        f_qnum = 1;
-      }
+  function onRoundChange() {
+    if (!f_exam_round) return;
+    if (f_exam_round === lastExamRound) return;
+    if (examRounds.length === 0) {
+      // examRounds 미적재 → onMount fallback 이 처리. 현재 호출은 skip.
       lastExamRound = f_exam_round;
-      refreshCompleteFlag();
+      return;
     }
-  });
+    const found = examRounds.find((r) => r.exam_round === f_exam_round);
+    if (found && found.next_question_number) {
+      f_qnum = found.next_question_number;
+    } else if (!found) {
+      f_qnum = 1;
+    }
+    lastExamRound = f_exam_round;
+    refreshCompleteFlag();
+  }
 
   function refreshCompleteFlag() {
     const found = examRounds.find((r) => r.exam_round === f_exam_round);
@@ -370,7 +376,7 @@
             <label class="text-xs text-dim">회차</label>
             {#if f_exam_round_mode === 'select'}
               <div class="flex gap-2">
-                <select bind:value={f_exam_round}
+                <select bind:value={f_exam_round} onchange={onRoundChange}
                   class="flex-1 px-3 py-2 bg-surface border border-default rounded text-sm text-text outline-none focus:border-accent">
                   <option value="">— 선택 —</option>
                   {#each examRounds as r}