裂变补图：中转站波动导致单张失败时只重生失败分镜

实测发现 codeproxy 偶发不稳，单套中某张图重试3次仍失败会记 error。
本次加按需补图：只重生标 error 的分镜，成功的图与 token 不浪费。

- 019迁移+模型：fission_tasks 加 source_task_id(新架构不扇出GenerationTask,
  补图需复刻首轮上下文:产品/operator key/张数,故落库回查)
- fission_image_retry：只补失败 role(引擎 target_role 单张重生,R2零改动),
  merge 回 images_json,全恢复则 status=image_done
- tasks.py：retry_fission_images Celery task,key归属源任务operator(基石B),
  幂等锁防重复补图
- api：POST /fission/{id}/notes/{seq}/retry-images,无失败分镜守卫 queued=false
- 前端：FissionNoteCard 失败提示改"重试补图"按钮+loading,父页轮询刷新

实测task5 seq1(hook图首轮codeproxy重试3次失败)补图跑通：只补hook(1024×1536
去AI化)、applied_proof原图不动、recovered=1 still_failed=0、status=image_done;
apiports503回落codeproxy gpt-5.5强档兜底;seq0无失败图守卫queued=false

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/alembic/versions/019_fission_source_task_id.py

@@ -0,0 +1,29 @@
+"""add source_task_id to fission_tasks
+
+Revision ID: 019
+Revises: 018
+Create Date: 2026-06-18
+
+裂变补图/重生需复刻首轮上下文(产品+operator key+张数)，故在 fission_tasks
+存下源 GenerationTask id。新架构不再扇出 GenerationTask，旧的 source_fission_id
+反查链断裂，本列补齐回查能力。
+"""
+from alembic import op
+import sqlalchemy as sa
+
+revision = "019"
+down_revision = "018"
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column(
+        "fission_tasks",
+        sa.Column("source_task_id", sa.BigInteger, nullable=True,
+                  comment="源 GenerationTask id（补图复刻上下文用）"),
+    )
+
+
+def downgrade():
+    op.drop_column("fission_tasks", "source_task_id")

backend/app/api/v1/fission.py

@@ -115,3 +115,44 @@ def get_fission_notes(
 
     return ok({"fission_id": ft.id, "status": ft.status,
                "fanout_count": ft.fanout_count, "notes": notes})
+
+
+@router.post("/fission/{fission_id}/notes/{seq}/retry-images")
+def retry_fission_note_images_endpoint(
+    fission_id: int,
+    seq: int,
+    current_user: Annotated[CurrentUser, Depends(require_write_permission)] = None,
+    db: Session = Depends(get_db),
+):
+    """补图：对某一套只重生标了 error 的失败分镜（中转站波动兜底）。
+
+    异步丢 Celery；前端轮询 GET /fission/{id}/notes 看 images 更新。
+    """
+    ft = db.query(FissionTask).filter(
+        FissionTask.id == fission_id,
+        FissionTask.workspace_id == current_user.workspace_id,
+    ).first()
+    if not ft:
+        raise_not_found("裂变任务不存在")
+
+    fn = db.query(FissionNote).filter(
+        FissionNote.fission_id == fission_id,
+        FissionNote.workspace_id == current_user.workspace_id,
+        FissionNote.seq == seq,
+    ).first()
+    if not fn:
+        raise_not_found("该套笔记不存在")
+
+    try:
+        images = json.loads(fn.images_json) if fn.images_json else []
+    except (ValueError, TypeError):
+        images = []
+    failed = [img.get("role") for img in images if img.get("error")]
+    if not failed:
+        return ok({"fission_id": fission_id, "seq": seq,
+                   "queued": False, "message": "该套无失败分镜，无需补图"})
+
+    from app.workers.tasks import retry_fission_images
+    retry_fission_images.delay(fission_id, fn.id)
+    return ok({"fission_id": fission_id, "seq": seq, "note_id": fn.id,
+               "queued": True, "failed_roles": failed})

backend/app/models/fission.py

@@ -29,6 +29,10 @@ class FissionTask(Base):
     source_note: Mapped[str | None] = mapped_column(
         Text, comment="爆款源笔记内容（文案+图描述，JSON存储）"
     )
+    # 源生成任务ID：补图/重生需复刻首轮上下文(产品+operator key+张数)时回查
+    source_task_id: Mapped[int | None] = mapped_column(
+        BigInteger, nullable=True, comment="源 GenerationTask id（补图复刻上下文用）"
+    )
     # 参考程度：low/mid/high
     reference_level: Mapped[str] = mapped_column(
         String(10), default="mid", nullable=False,

backend/app/services/fission_image_retry.py

@@ -0,0 +1,105 @@
+"""
+app/services/fission_image_retry.py — 第11环裂变 失败分镜补图（中转站波动兜底）
+
+实测发现 codeproxy 偶发不稳，单套中某张图重试3次仍失败会记 error 落库。
+本模块对某一套(FissionNote)只补 images_json 里标了 error 的分镜：成功的不动，
+失败的用引擎 target_role 单张重生(R2 零改动)，merge 回 images_json。
+
+🔴 生图引擎零改动；只补失败 role，避免整套重生浪费已成功的图与 token。
+"""
+import logging
+
+from sqlalchemy.orm import Session
+
+logger = logging.getLogger(__name__)
+
+
+def _failed_roles(images: list[dict]) -> list[str]:
+    """从 images_json 解析出标了 error 的分镜 role 列表。"""
+    return [img.get("role", "") for img in images if img.get("error") and img.get("role")]
+
+
+def retry_fission_note_images(
+    db: Session, clients, ft, product: dict, image_count: int, note_id: int,
+) -> dict:
+    """对单套 FissionNote 只补失败分镜。返回 {seq, retried, recovered, still_failed}。"""
+    import asyncio
+    import json as _json
+    import os
+
+    from app.models.fission import FissionNote
+    from app.core.config import get_settings
+    from app.services.ai_engine.image_gen import generate_storyboard_images
+    from app.services.ai_engine.image_postprocessor import process_image
+    from app.workers.pipeline_io import _resolve_image_path
+
+    fn = db.query(FissionNote).filter(FissionNote.id == note_id).first()
+    if not fn:
+        return {"seq": None, "retried": 0, "recovered": 0, "still_failed": 0}
+
+    try:
+        images = _json.loads(fn.images_json) if fn.images_json else []
+    except (ValueError, TypeError):
+        images = []
+    try:
+        note = _json.loads(fn.note_json) if fn.note_json else {}
+    except (ValueError, TypeError):
+        note = {}
+
+    failed = _failed_roles(images)
+    if not failed:
+        return {"seq": fn.seq, "retried": 0, "recovered": 0, "still_failed": 0}
+
+    # 参考图沿用源产品同一张（与首轮生图一致）
+    reference_images = None
+    _img_path = _resolve_image_path(product.get("image_path", ""))
+    if _img_path and os.path.isfile(_img_path):
+        try:
+            with open(_img_path, "rb") as f:
+                reference_images = [f.read()]
+        except Exception as e:  # noqa: BLE001
+            logger.warning("裂变补图参考图读取失败，无参考图模式: %s", e)
+
+    upload_base = get_settings().UPLOAD_ABS_ROOT
+    img_dir = os.path.join(upload_base, str(ft.workspace_id), f"fission_{ft.id}", str(fn.seq))
+    os.makedirs(img_dir, exist_ok=True)
+
+    recovered = 0
+    # role → 在 images 列表里的位置(保持原顺序/seq 不乱)
+    role_idx = {img.get("role"): i for i, img in enumerate(images)}
+    for role in failed:
+        try:
+            results = asyncio.run(generate_storyboard_images(
+                client=clients, note=note, product=product,
+                image_count=image_count, reference_images=reference_images,
+                target_role=role,
+            ))
+        except Exception as exc:  # noqa: BLE001
+            logger.error("裂变补图 seq=%s role=%s 仍失败: %s", fn.seq, role, exc)
+            continue
+        r = next((x for x in results if x.get("role") == role), None)
+        if not r or r.get("error") or not r.get("image_bytes"):
+            logger.warning("裂变补图 seq=%s role=%s 引擎返回空/error", fn.seq, role)
+            continue
+        try:
+            processed = process_image(r["image_bytes"], aspect_ratio="3:4", resample_strength=1)
+        except Exception:  # noqa: BLE001
+            processed = r["image_bytes"]
+        idx = role_idx.get(role, len(images))
+        seq_no = idx + 1
+        fname = f"{seq_no:02d}_{role}.jpg"
+        with open(os.path.join(img_dir, fname), "wb") as f:
+            f.write(processed)
+        entry = {"role": role, "seq": seq_no,
+                 "url": f"/uploads/{ft.workspace_id}/fission_{ft.id}/{fn.seq}/{fname}"}
+        if idx < len(images):
+            images[idx] = entry
+        else:
+            images.append(entry)
+        recovered += 1
+
+    fn.images_json = _json.dumps(images, ensure_ascii=False)
+    still = len(_failed_roles(images))
+    fn.status = "image_done" if still == 0 else fn.status
+    db.commit()
+    return {"seq": fn.seq, "retried": len(failed), "recovered": recovered, "still_failed": still}

backend/app/services/fission_service.py

@@ -51,6 +51,7 @@ def create_fission(
     ft = FissionTask(
         workspace_id=current_user.workspace_id,
         source_note=json.dumps(source_note, ensure_ascii=False),
+        source_task_id=source_task_id,
         reference_level=level, fanout_count=n, status="generating",
     )
     db.add(ft); db.commit(); db.refresh(ft)

backend/app/workers/tasks.py

@@ -286,3 +286,72 @@ def run_fission_pipeline(self, fission_id: int, source_task_id: int) -> dict:
     finally:
         _r.delete(lock_key)
         db.close()
+
+
+@celery_app.task(
+    bind=True,
+    name="app.workers.tasks.retry_fission_images",
+    max_retries=1,
+    default_retry_delay=20,
+    queue="generation",
+)
+def retry_fission_images(self, fission_id: int, note_id: int) -> dict:
+    """裂变补图：对某一套只重生标了 error 的失败分镜（中转站波动兜底）。
+
+    只接收 id（基石B），不接收 key。复用源产品参考图与 image_count。
+    解密 key→构建 clients→委托 fission_image_retry.retry_fission_note_images。
+    """
+    logger.info("retry_fission_images start: fission_id=%s note_id=%s", fission_id, note_id)
+    lock_key = f"fission:retry:lock:{note_id}"
+    import redis as _redis
+    from app.core.config import get_settings as _gs
+    _r = _redis.from_url(_gs().REDIS_URL, decode_responses=True)
+    if not _r.set(lock_key, "1", nx=True, ex=1800):
+        logger.warning("retry_fission_images 跳过(已在跑): note_id=%s", note_id)
+        return {"note_id": note_id, "status": "skipped_locked"}
+
+    db = _get_db()
+    try:
+        from app.models.fission import FissionTask
+        from app.models.task import GenerationTask
+        from app.models.product import Product
+        from app.workers.pipeline_steps import (
+            decrypt_user_key, build_clients_and_clear_key, build_product_dict,
+        )
+        from app.services.fission_image_retry import retry_fission_note_images
+
+        ft = db.query(FissionTask).filter(FissionTask.id == fission_id).first()
+        if not ft:
+            return {"note_id": note_id, "status": "not_found"}
+        if not ft.source_task_id:
+            return {"note_id": note_id, "status": "no_source_task"}
+        src = db.query(GenerationTask).filter(
+            GenerationTask.id == ft.source_task_id,
+        ).first()
+        if not src:
+            return {"note_id": note_id, "status": "source_task_gone"}
+        product_row = db.query(Product).filter(Product.id == src.product_id).first()
+        if not product_row:
+            return {"note_id": note_id, "status": "no_product"}
+
+        # key 归属源任务 operator，与首轮生图一致（基石B：不接收明文 key）
+        plain_key = decrypt_user_key(db, src.operator_id, ft.workspace_id)
+        clients = build_clients_and_clear_key(plain_key)
+        plain_key = None  # 用完即清，基石B
+
+        product = build_product_dict(product_row)
+        image_count = max(1, (src.image_count or 3))
+        result = retry_fission_note_images(
+            db, clients, ft, product, image_count, note_id,
+        )
+        result["status"] = "completed"
+        return result
+    except Exception as exc:  # noqa: BLE001
+        logger.error("retry_fission_images failed: note_id=%s err=%s", note_id, exc)
+        exhausted = self.request.retries >= self.max_retries
+        if exhausted:
+            return {"note_id": note_id, "status": "failed", "error": str(exc)}
+        raise self.retry(exc=exc)
+    finally:
+        _r.delete(lock_key)
+        db.close()