Avoid NullPointerException when customChange has no "class" attribute

[danielthegray]

Environment

Liquibase Version: all

Liquibase Integration & Version: all

Liquibase Extension(s) & Version: all

Database Vendor & Version: all

Operating System Type & Version: all

Pull Request Type

• Bug fix (non-breaking change which fixes an issue.)
• Enhancement/New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

If a customChange node is missing the "class" attribute (either by typo, or mis-indentation) a NullPointerException is thrown:

Caused by: java.lang.NullPointerException
    at java.lang.Class.forName0(Native Method) ~[?:?]
    at java.lang.Class.forName(Class.java:398) ~[?:?]
    at liquibase.change.custom.CustomChangeWrapper.customLoadLogic(CustomChangeWrapper.java:335) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.change.AbstractChange.load(AbstractChange.java:719) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.change.custom.CustomChangeWrapper.load(CustomChangeWrapper.java:312) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.changelog.ChangeSet.toChange(ChangeSet.java:480) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.changelog.ChangeSet.handleChildNode(ChangeSet.java:413) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]   
    at liquibase.changelog.ChangeSet.handleChildNode(ChangeSet.java:409) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]   
    at liquibase.changelog.ChangeSet.load(ChangeSet.java:337) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.changelog.DatabaseChangeLog.createChangeSet(DatabaseChangeLog.java:606) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.changelog.DatabaseChangeLog.handleChildNode(DatabaseChangeLog.java:336) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]
    at liquibase.changelog.DatabaseChangeLog.load(DatabaseChangeLog.java:305) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?] 
    at liquibase.parser.core.yaml.YamlChangeLogParser.parse(YamlChangeLogParser.java:77) ~[usafe-cli-1.0.1-SNAPSHOT-all.jar:?]

Steps To Reproduce

Create a customChange node with no class attribute, and you will see this exception.

Actual Behavior

Check description.

Expected/Desired Behavior

A nicer exception should appear with a better error message.

Fast Track PR Acceptance Checklist:

• Build is successful and all new and existing tests pass
• Added Unit Test(s)
• Added Integration Test(s)
• Added Test Harness Test(s)
• Documentation Updated

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Dev Handoff Notes (Internal Use)

Links

• Fixed Issue: Stand alone PR
• Test Results: https://github.com/liquibase/liquibase/pull/1648/checks

Testing

• Steps to Reproduce: See above (use yaml format)
• Guidance:
  • Impact: Just adds a check for a missing argument

Dev Verification

Code review and ensured new automated test is good

Manual Tests

Verify update shows correct error message when class attribute is not specified.

• create a changelog with customChange changeset, but do not specify class attribute

• liquibase --log-level INFO update --changelog-file changelog.yaml

• Custom change node has no 'class' attribute! error message is shown

Verify update is successful when class attribute is specified.

• specify 'class' attribute in your changelog

• liquibase update --changelog-file changelog.yaml

• update is successful

┆Issue is synchronized with this Jira Bug by Unito

[molivasdat]

Thanks @danielthegray for fixing this issue. Always appreciated when our core team helps fix issues.

[nvoxland]

The changes look good, thanks!

[yodzhubeiskyi]

Verify update shows correct error message when class attribute is not specified. PASS

Unexpected error running Liquibase: Error parsing changelog.yaml

liquibase.exception.CommandExecutionException: liquibase.exception.LiquibaseException: Unexpected error running Liquibase: Custom change node has no 'class' attribute!

Verify update is successful when class attribute is specified. PASS

Liquibase version [Core: //improve-missing-class-name-custom-change-error/1452/fc0771/2022-02-09 21:38+0000, Pro: master/591/f653ec/2022-02-09T18:09:13Z] #1452