{"record":{"id":"63c55b5d0f26d5de","repo":"flowable/flowable-engine","slug":"task-name-list-is-empty-63c55b","errorCode":null,"errorMessage":"Task name list is empty","messagePattern":"Task name list is empty","errorType":"validation","errorClass":"ActivitiIllegalArgumentException","httpStatus":400,"severity":"error","filePath":"modules/flowable5-engine/src/main/java/org/activiti/engine/impl/HistoricTaskInstanceQueryImpl.java","lineNumber":381,"sourceCode":"    }\n\n    @Override\n    public HistoricTaskInstanceQuery taskName(String taskName) {\n        if (inOrStatement) {\n            this.currentOrQueryObject.taskName = taskName;\n        } else {\n            this.taskName = taskName;\n        }\n        return this;\n    }\n\n    @Override\n    public HistoricTaskInstanceQuery taskNameIn(List<String> taskNameList) {\n        if (taskNameList == null) {\n            throw new ActivitiIllegalArgumentException(\"Task name list is null\");\n        }\n        if (taskNameList.isEmpty()) {\n            throw new ActivitiIllegalArgumentException(\"Task name list is empty\");\n        }\n\n        if (taskName != null) {\n            throw new ActivitiIllegalArgumentException(\"Invalid query usage: cannot set both taskNameIn and taskName\");\n        }\n        if (taskNameLike != null) {\n            throw new ActivitiIllegalArgumentException(\"Invalid query usage: cannot set both taskNameIn and taskNameLike\");\n        }\n        if (taskNameLikeIgnoreCase != null) {\n            throw new ActivitiIllegalArgumentException(\"Invalid query usage: cannot set both taskNameIn and taskNameLikeIgnoreCase\");\n        }\n\n        if (inOrStatement) {\n            currentOrQueryObject.taskNameList = taskNameList;\n        } else {\n            this.taskNameList = taskNameList;\n        }\n        return this;","sourceCodeStart":363,"sourceCodeEnd":399,"githubUrl":"https://github.com/flowable/flowable-engine/blob/d6d39ce1c69ff244f2d9dc6af756a9b95e865586/modules/flowable5-engine/src/main/java/org/activiti/engine/impl/HistoricTaskInstanceQueryImpl.java#L363-L399","documentation":"HistoricTaskInstanceQueryImpl.taskNameIn() throws ActivitiIllegalArgumentException when the task name list is non-null but empty. An empty IN list is invalid, so at least one task name must be supplied. Additionally, taskNameIn is mutually exclusive with taskName/taskNameLike, which the library checks right after this guard.","triggerScenarios":"Calling historicTaskInstanceQuery.taskNameIn(new ArrayList<>()) or any empty List<String>.","commonSituations":"Search box with multiple keywords that the user left blank; splitting an empty string into an empty list (\"\".split(\",\") nuances aside); passing an empty filter set from a saved search.","solutions":["Check !names.isEmpty() before calling taskNameIn; skip the filter when empty.","Verify how the list is built — ensure at least one name is collected before query execution.","Ensure you are not mixing taskNameIn with taskName or taskNameLike, which throws a separate invalid-usage error."],"exampleFix":"// before\nquery.taskNameIn(names); // empty list\n\n// after\nif (names != null && !names.isEmpty()) {\n    query.taskNameIn(names);\n}","handlingStrategy":"validation","validationCode":"if (names != null && !names.isEmpty()) {\n    if (useNameEquals) { throw new IllegalStateException(\"taskNameIn is mutually exclusive with taskName\"); }\n    query.taskNameIn(names);\n}","typeGuard":"static boolean canApplyNameIn(List<String> names, String taskName, String taskNameLike) { return names != null && !names.isEmpty() && taskName == null && taskNameLike == null; }","tryCatchPattern":"try {\n    query.taskNameIn(names);\n} catch (org.activiti.engine.ActivitiIllegalArgumentException e) {\n    // covers both empty-list and taskName/taskNameLike conflicts\n    log.warn(\"Invalid task name filter: {}\", e.getMessage());\n}","preventionTips":["Guard against empty lists AND against combining taskNameIn with taskName/taskNameLike.","Treat an empty keyword list as 'no name filter' and skip the call.","Encode the mutual-exclusion rule in your own query DTO so invalid combinations cannot be built."],"tags":["java","activiti","query-validation","empty-list"],"backgroundTag":"empty-required-field","analyzedSha":"d6d39ce1c69ff244f2d9dc6af756a9b95e865586","analyzedAt":"2026-09-11T06:41:19.413Z","contentChangedAt":"2026-09-11T06:41:19.413Z","schemaVersion":2},"datasetVersion":"2026-09-18T11:17:12.947Z"}