错题处理失败时直接显示具体错误信息。

backend/app/models/user.py

@@ -133,6 +133,7 @@ class WrongQuestion(Base):
     solution_text: Mapped[str | None] = mapped_column(Text, nullable=True)
     mark_regions_json: Mapped[str | None] = mapped_column(Text, nullable=True)
     annotated_image_path: Mapped[str | None] = mapped_column(String(512), nullable=True)
+    error_message: Mapped[str | None] = mapped_column(Text, nullable=True)
     status: Mapped[WrongQuestionStatus] = mapped_column(
         Enum(WrongQuestionStatus), default=WrongQuestionStatus.pending
     )

backend/app/routers/wrong_questions.py

@@ -19,6 +19,13 @@ from app.services.student_access import get_student_for_user
 router = APIRouter(tags=["wrong_questions"])
 
 
+def _short_error(exc: BaseException, prefix: str = "") -> str:
+    msg = str(exc).strip() or type(exc).__name__
+    if len(msg) > 500:
+        msg = msg[:500] + "…"
+    return f"{prefix}{msg}" if prefix else msg
+
+
 def _parse_mark_regions(raw: str | None) -> list[dict] | None:
     if not raw:
         return None
@@ -43,6 +50,7 @@ def _wq_to_out(wq: WrongQuestion) -> WrongQuestionOut:
         solution_text=wq.solution_text,
         mark_regions=_parse_mark_regions(wq.mark_regions_json),
         has_annotated_image=bool(wq.annotated_image_path),
+        error_message=wq.error_message,
         status=wq.status,
         created_at=wq.created_at,
     )
@@ -74,6 +82,7 @@ async def _run_ai_pipeline(wq: WrongQuestion, db: Session, ocr_lines: list[dict]
     wq.solution_approach = approach
     wq.solution_text = solution_body if approach else solution_full
     wq.status = WrongQuestionStatus.solved
+    wq.error_message = None
 
 
 def _process_wrong_question(question_id: uuid.UUID):
@@ -88,22 +97,26 @@ def _process_wrong_question(question_id: uuid.UUID):
         if wq is None:
             return
 
+        wq.error_message = None
         image_full = Path(settings.UPLOAD_DIR) / wq.image_path
         try:
             ocr_result = ocr_service.run_ocr_with_regions(str(image_full))
             ocr_text = ocr_result["text"]
             ocr_lines = ocr_result["lines"]
             wq.ocr_raw_text = ocr_text or None
-            wq.status = WrongQuestionStatus.ocr_done if ocr_text else WrongQuestionStatus.failed
+            if not ocr_text:
+                wq.status = WrongQuestionStatus.failed
+                wq.error_message = "OCR 未识别到文字，请拍摄更清晰、光线充足的题目照片"
+                db.commit()
+                return
+            wq.status = WrongQuestionStatus.ocr_done
             db.commit()
-        except Exception:
+        except Exception as exc:
             wq.status = WrongQuestionStatus.failed
+            wq.error_message = _short_error(exc, "OCR 识别失败：")
             db.commit()
             return
 
-        if not ocr_text:
-            return
-
         import asyncio
 
         loop = asyncio.new_event_loop()
@@ -111,8 +124,9 @@ def _process_wrong_question(question_id: uuid.UUID):
         try:
             loop.run_until_complete(_run_ai_pipeline(wq, db, ocr_lines, ocr_text))
             db.commit()
-        except Exception:
-            wq.status = WrongQuestionStatus.ocr_done
+        except Exception as exc:
+            wq.status = WrongQuestionStatus.failed
+            wq.error_message = _short_error(exc, "AI 处理失败：")
             db.commit()
         finally:
             loop.close()
@@ -293,6 +307,7 @@ def retry_ocr(
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="错题不存在")
 
     wq.status = WrongQuestionStatus.pending
+    wq.error_message = None
     db.commit()
     background_tasks.add_task(_process_wrong_question, wq.id)
     return _wq_to_out(wq)

backend/app/schemas/__init__.py

@@ -237,6 +237,7 @@ class WrongQuestionOut(BaseModel):
     solution_text: str | None
     mark_regions: list[dict] | None = None
     has_annotated_image: bool = False
+    error_message: str | None = None
     status: WrongQuestionStatusEnum
     created_at: datetime
 

backend/app/services/migrate.py

@@ -75,6 +75,8 @@ def run_migrations() -> None:
             wq_alters.append("ADD COLUMN mark_regions_json TEXT")
         if "annotated_image_path" not in wq_columns:
             wq_alters.append("ADD COLUMN annotated_image_path VARCHAR(512)")
+        if "error_message" not in wq_columns:
+            wq_alters.append("ADD COLUMN error_message TEXT")
         if wq_alters:
             with engine.begin() as conn:
                 for clause in wq_alters: