Bulk output flag throws error

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#11 opened on Aug 10, 2026 0 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty: 2/5
Estimated time: 1-3 hours
Newbie friendliness: 76/100

Issue type: Bug
Clarity: Clearly specified
Activity status: Quiet
Tech stack: java
Domain: cli

Research direction

Start with src/main/java/be/ugent/idlab/knows/mappingweaver/cli/Main.java, especially the option parsing at line 106, and reproduce the failure using the --bulk flag. Trace the parsed value and verify that enabling --bulk no longer produces the reported ClassCastException and allows the command to run.

Written by the indexing model from the issue text.

Description

While trying to deduplicate the output (cf. #7), I tried running MappingWeaver with the --bulk flag, only to find that enabling this option immediately results in an error:

Exception in thread "main" java.lang.RuntimeException: java.lang.ClassCastException: class java.lang.Boolean cannot be cast to class java.lang.String (java.lang.Boolean and java.lang.String are in module java.base of loader 'bootstrap')
        at be.ugent.idlab.knows.mappingweaver.cli.Main.parseAndRun(Main.java:172)
        at be.ugent.idlab.knows.mappingweaver.cli.Main.main(Main.java:58)
Caused by: java.lang.ClassCastException: class java.lang.Boolean cannot be cast to class java.lang.String (java.lang.Boolean and java.lang.String are in module java.base of loader 'bootstrap')
        at be.ugent.idlab.knows.mappingweaver.cli.Main.parseAndRun(Main.java:106)
        ... 1 more

The culprit seems to be an implicit type cast when parsing the option in mappingweaver/cli/Main.java#L106.

Dominant language: Java
Stars: 3
Forks: 1
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