Merge branch 'feature/remove_variables' into dev

workflow-engine-server/src/main/java/cn/axzo/workflow/server/controller/web/bpmn/BpmnProcessInstanceController.java

@@ -51,6 +51,7 @@ import cn.axzo.workflow.common.valid.group.ValidGroup;
 import cn.axzo.workflow.core.conf.OmsWorkspaceProperty;
 import cn.axzo.workflow.core.engine.cmd.CustomGetModelDocsCmd;
 import cn.axzo.workflow.core.repository.entity.ExtAxProcessLog;
+import cn.axzo.workflow.core.repository.entity.ExtAxProcessSign;
 import cn.axzo.workflow.core.repository.mapper.ExtAxModelDocMapper;
 import cn.axzo.workflow.core.service.BpmnProcessInstanceService;
 import cn.axzo.workflow.core.service.BpmnProcessTaskService;
@@ -624,7 +625,8 @@ public class BpmnProcessInstanceController extends BasicPopulateAvatarController
     @Operation(summary = "获取签署业务流程最后替换的文档 fileKey 集合")
     @GetMapping("/final/docs")
     public CommonResponse<List<SignFileDTO>> getProcessInstanceFinalDocs(@NotBlank(message = "流程实例 ID 不能为空") @RequestParam(required = false) String processInstanceId) {
-        return success(extAxProcessSignService.findByProcessInstanceId(processInstanceId).getFileArchive());
+        ExtAxProcessSign sign = extAxProcessSignService.findByProcessInstanceId(processInstanceId);
+        return success(Objects.nonNull(sign) ? sign.getFileArchive() : null);
     }
 
     /**