ElasticsearchIllegalArgumentException[failed to execute script]

这个错误有人解释下吗?
{
"status": 400,
"message": "ElasticsearchIllegalArgumentException[failed to execute script]; nested: GroovyScriptCompilationException[MultipleCompilationErrorsException[startup failed:\n317d0536801260135faa2f66355204a49433a1aa: 1: \nclass org.codehaus.groovy.ast.expr.TernaryExpression, with its value '(ctx._source.favorite.contains(member)) ? (ctx.op = none) : ctx._source.favorite', is a bad expression as the left hand side of an assignment operator at line: 1 column: 80. File: 317d0536801260135faa2f66355204a49433a1aa @ line 1, column 80.\n \"none\" : ctx._source.favorite += member\n ^\n\n1 error\n]]; ",
"body": {
"error": "ElasticsearchIllegalArgumentException[failed to execute script]; nested: GroovyScriptCompilationException[MultipleCompilationErrorsException[startup failed:\n317d0536801260135faa2f66355204a49433a1aa: 1: \nclass org.codehaus.groovy.ast.expr.TernaryExpression, with its value '(ctx._source.favorite.contains(member)) ? (ctx.op = none) : ctx._source.favorite', is a bad expression as the left hand side of an assignment operator at line: 1 column: 80. File: 317d0536801260135faa2f66355204a49433a1aa @ line 1, column 80.\n \"none\" : ctx._source.favorite += member\n ^\n\n1 error\n]]; ",
"status": 400
},
"displayName": "BadRequest"
}