fix(bpm):修复流程预测时由于流程未开始或流程未真正抵达执行节点，无法获取execution导致的Expression流程表达式执行报错问题

yudao-module-bpm/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/candidate/expression/BpmTaskAssignLeaderExpression.java

@@ -7,6 +7,7 @@ import cn.iocoder.yudao.module.system.api.dept.dto.DeptRespDTO;
 import cn.iocoder.yudao.module.system.api.user.AdminUserApi;
 import cn.iocoder.yudao.module.system.api.user.dto.AdminUserRespDTO;
 import org.flowable.engine.delegate.DelegateExecution;
+import org.flowable.engine.impl.persistence.entity.ExecutionEntityImpl;
 import org.flowable.engine.runtime.ProcessInstance;
 import org.springframework.stereotype.Component;
 import org.springframework.util.Assert;
@@ -41,11 +42,34 @@ public class BpmTaskAssignLeaderExpression {
      * @param level 指定级别
      * @return 指定级别的领导
      */
-    public Set<Long> calculateUsers(DelegateExecution execution, int level) {
+    public Set<Long> calculateUsers(ExecutionEntityImpl execution, Long level) {
-        Assert.isTrue(level > 0, "level 必须大于 0");
         // 获得发起人
         ProcessInstance processInstance = processInstanceService.getProcessInstance(execution.getProcessInstanceId());
-        Long startUserId = NumberUtils.parseLong(processInstance.getStartUserId());
+        return calculateUsers(NumberUtils.parseLong(processInstance.getStartUserId()), level);
+    }
+
+    /**
+     * 计算审批的候选人
+     *
+     * @param processInstanceId 流程实例id
+     * @param level 指定级别
+     * @return 指定级别的领导
+     */
+    public Set<Long> calculateUsers(String processInstanceId, Long level) {
+        ProcessInstance processInstance = processInstanceService.getProcessInstance(processInstanceId);
+        return calculateUsers(NumberUtils.parseLong(processInstance.getStartUserId()), level);
+    }
+
+
+    /**
+     * 计算审批的候选人
+     *
+     * @param startUserId 发起人
+     * @param level 指定级别
+     * @return 指定级别的领导
+     */
+    public Set<Long> calculateUsers(Long startUserId, Long level) {
+        Assert.isTrue(level > 0, "level 必须大于 0");
         // 获得对应 leve 的部门
         DeptRespDTO dept = null;
         for (int i = 0; i < level; i++) {

yudao-module-bpm/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/candidate/expression/BpmTaskAssignStartUserExpression.java

@@ -33,4 +33,26 @@ public class BpmTaskAssignStartUserExpression {
         return SetUtils.asSet(startUserId);
     }
 
+    /**
+     * 计算审批的候选人
+     *
+     * @param startUserId 发起人id
+     * @return 发起人
+     */
+    public Set<Long> calculateUsers(Long startUserId) {
+        return SetUtils.asSet(startUserId);
+    }
+
+    /**
+     * 计算审批的候选人
+     *
+     * @param processInstanceId 流程实例id
+     * @return 发起人
+     */
+    public Set<Long> calculateUsers(String processInstanceId) {
+        ProcessInstance processInstance = processInstanceService.getProcessInstance(processInstanceId);
+        Long startUserId = NumberUtils.parseLong(processInstance.getStartUserId());
+        return SetUtils.asSet(startUserId);
+    }
+
 }

yudao-module-bpm/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/enums/BpmnVariableConstants.java

@@ -96,4 +96,8 @@ public class BpmnVariableConstants {
      */
     public static final String TASK_SIGN_PIC_URL = "TASK_SIGN_PIC_URL";
 
+    /**
+     * 流程实例的变量 - 流程实例id
+     */
+    public static final String PROCESS_INSTANCE_ID = "PROCESS_INSTANCE_ID";
 }

yudao-module-bpm/src/main/java/cn/iocoder/yudao/module/bpm/framework/flowable/core/util/FlowableUtils.java

@@ -5,6 +5,7 @@ import cn.hutool.core.util.ObjectUtil;
 import cn.hutool.extra.spring.SpringUtil;
 import cn.iocoder.yudao.framework.common.core.KeyValue;
 import cn.iocoder.yudao.framework.common.util.json.JsonUtils;
+import cn.iocoder.yudao.framework.security.core.util.SecurityFrameworkUtils;
 import cn.iocoder.yudao.framework.tenant.core.context.TenantContextHolder;
 import cn.iocoder.yudao.framework.tenant.core.util.TenantUtils;
 import cn.iocoder.yudao.module.bpm.controller.admin.definition.vo.form.BpmFormFieldVO;
@@ -30,6 +31,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.concurrent.Callable;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
 import static cn.iocoder.yudao.framework.common.util.collection.CollectionUtils.convertList;
@@ -355,6 +358,33 @@ public class FlowableUtils {
     }
 
     public static Object getExpressionValue(Map<String, Object> variable, String expressionString) {
+        // 替换方法参数中的 execution 为流程实例id或userId，因为流程预测时获取不到execution对象
+        // 例如将 calculateUsers(execution, 1) 替换为 calculateUsers('xxx-xxx-xxx-xxx', 1)
+        Pattern pattern = Pattern.compile("\\(([^)]*)\\)");
+        Matcher matcher = pattern.matcher(expressionString);
+        StringBuilder sb = new StringBuilder();
+        while (matcher.find()) {
+            // 获取方法参数列表
+            String args = matcher.group(1);
+            // 用逗号分隔参数并逐个替换精确匹配 execution 的部分
+            String[] params = args.split(",");
+            for (int i = 0; i < params.length; i++) {
+                if ("execution".equals(params[i].trim())) {
+                    // 流程已开始
+                    if(ObjectUtil.isNotEmpty(variable.get(BpmnVariableConstants.PROCESS_INSTANCE_ID))) {
+                        String processInstanceId = variable.get(BpmnVariableConstants.PROCESS_INSTANCE_ID).toString();
+                        params[i] = "'" + processInstanceId + "'";
+                    } else {
+                        //流程未开始
+                        params[i] = Objects.requireNonNull(SecurityFrameworkUtils.getLoginUserId()).toString();
+                    }
+                }
+            }
+            String newArgs = String.join(", ", params);
+            matcher.appendReplacement(sb, "(" + newArgs + ")");
+        }
+        matcher.appendTail(sb);
+        expressionString = sb.toString();
         VariableContainer variableContainer = new MapDelegateVariableContainer(variable, VariableContainer.empty());
         return getExpressionValue(variableContainer, expressionString);
     }

yudao-module-bpm/src/main/java/cn/iocoder/yudao/module/bpm/service/task/BpmProcessInstanceServiceImpl.java

@@ -46,6 +46,7 @@ import cn.iocoder.yudao.module.system.api.user.dto.AdminUserRespDTO;
 import jakarta.annotation.Resource;
 import jakarta.validation.Valid;
 import lombok.extern.slf4j.Slf4j;
+import org.apache.commons.lang3.StringUtils;
 import org.flowable.bpmn.constants.BpmnXMLConstants;
 import org.flowable.bpmn.model.*;
 import org.flowable.engine.HistoryService;
@@ -766,9 +767,11 @@ public class BpmProcessInstanceServiceImpl implements BpmProcessInstanceService
                 .businessKey(businessKey)
                 .variables(variables);
         // 3.1 创建流程 ID
+        String processInstanceId = null;
         BpmModelMetaInfoVO.ProcessIdRule processIdRule = processDefinitionInfo.getProcessIdRule();
         if (processIdRule != null && Boolean.TRUE.equals(processIdRule.getEnable())) {
-            processInstanceBuilder.predefineProcessInstanceId(processIdRedisDAO.generate(processIdRule));
+            processInstanceId = processIdRedisDAO.generate(processIdRule);
+            processInstanceBuilder.predefineProcessInstanceId(processInstanceId);
         }
         // 3.2 流程名称
         BpmModelMetaInfoVO.TitleSetting titleSetting = processDefinitionInfo.getTitleSetting();
@@ -784,6 +787,9 @@ public class BpmProcessInstanceServiceImpl implements BpmProcessInstanceService
         }
         // 3.3 发起流程实例
         ProcessInstance instance = processInstanceBuilder.start();
+        // 将流程实例id保存到流程变量里，用于无法获取execution时获取流程实例id
+        processInstanceId = StringUtils.defaultIfBlank(processInstanceId, instance.getId());
+        runtimeService.setVariable(instance.getProcessInstanceId(),BpmnVariableConstants.PROCESS_INSTANCE_ID,processInstanceId);
         return instance.getId();
     }