Malformed regular expression file expecting object – How to solve this OpenSearch exception

Opster Team

Aug-23, Version: 1-2.9

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Briefly, this error occurs when OpenSearch encounters an incorrectly formatted regular expression file. The system is expecting an object but is not receiving it in the expected format. This could be due to a syntax error, incorrect file type, or a missing or misplaced bracket. To resolve this issue, you should first check the syntax of your regular expression file. Ensure that it is correctly formatted and all brackets are properly placed. If the syntax is correct, check the file type. It should be a .json file. Lastly, ensure that the file is not corrupted or damaged.

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This guide will help you check for common problems that cause the log ” malformed regular expression file; expecting ‘object’ ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: .

Log Context

Log “malformed regular expression file; expecting ‘object'” class name is We extracted the following from OpenSearch source code for those seeking an in-depth context :

 throw new OpenSearchParseException("malformed regular expression file; should continue with 'array' after 'object'");
 }  token = yamlParser.nextToken();
 if (token != XContentParser.Token.START_OBJECT) {
 throw new OpenSearchParseException("malformed regular expression file; expecting 'object'");
 }  while (token == XContentParser.Token.START_OBJECT) {
 token = yamlParser.nextToken();


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