Error parsing when running Liquibase

Applies to

• Liquibase Pro
• Liquibase Open Source (Community)

Conditions

• Any version of Liquibase Pro or Open Source
• Using modeled changesets (i.e., YAML, XML, or JSON)

Issue Summary

When running Liquibase, the below error occurs. This error indicates that the Liquibase changeset is missing required syntax.

Error Message

ERROR: Exception Details
ERROR: Exception Primary Class: ClassCastException
ERROR: Exception Primary Reason: java.util.ArrayList cannot be cast to java.util.Map
ERROR: Exception Primary Source: Microsoft SQL Server 15.00.4345

Unexpected error running Liquibase: Error parsing /file/path.yaml : Syntax error in file file/path/changeset.yaml: java.util.ArrayList cannot be cast to java.util.Map

Root Cause

The error is caused by a missing databaseChangeLog: line at the top of the changeset YAML file. Without this header, Liquibase cannot parse the changeset properly, leading to a type mismatch when interpreting the YAML structure.

This applies to XML and JSON changesets as well. The proper Liquibase changeset syntax is required for YAML, XML, and JSON changesets and changelogs.

Resolution

1. Open the changeset file where the error occurs.

2. Ensure the file begins with the required syntax.

   • YAML

     • databaseChangeLog:

   • XML
     

     • <databaseChangeLog
         xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns:ext="http://www.liquibase.org/xml/ns/dbchangelog-ext"
         xmlns:pro="http://www.liquibase.org/xml/ns/pro"
         xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
         http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd
         http://www.liquibase.org/xml/ns/dbchangelog-ext
         http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-ext.xsd
         http://www.liquibase.org/xml/ns/pro
         http://www.liquibase.org/xml/ns/pro/liquibase-pro-latest.xsd">

   • JSON

     • {
           "databaseChangeLog": [
               {
                   ...

3. Add the appropriate structure underneath if it’s missing.

   Example corrected YAML changeset:

   databaseChangeLog:
     - changeSet:
       id: 1
       author: your.name
       labels: example_label
       context: example_context
       comment: example_comment
       changes:
         - sql: Your SQL script here

4. Save the file and rerun Liquibase.

5. If the error persists, double-check for other syntax issues or indentation problems. YAML is sensitive to formatting, so ensure proper alignment when using a YAML changeset.

You can find full examples for each type here:

• Example Changelogs: YAML Format
• Example Changelogs: XML Format
• Example Changelogs: JSON Format

Related Article(s)

• Changelogs