Warning log when an enum value cannot be parsed

[Mattias-Sehlstedt]

I face issues back and forth with how negative enums are treated. The cause of it is due to my locale, and the exact cause is described here. A recent PR made so that a TypeScriptAxios test references a schema with a negative enum, which means that a developer with a "bad locale" will have an unexpected nullpointer when running the tests.

This PR changes so that this case is handled with a warning log and that processing continues, as per the behavior of most other enum interpreters. This change makes it so someone encountering this issue is less like to suffer from it and makes it clearer to them why it is occurring.

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---

Summary by cubic

Log a warning and continue when a numeric enum value is null to prevent crashes caused by locale-specific parsing of negative enums. This stabilizes TypeScript and N4JS client generation and avoids unexpected NPEs in tests.

• Bug Fixes
  • Skip null values in numericEnumValuesToEnumTypeUnion and log a warning instead of calling toString.
  • Applies to AbstractTypeScriptClientCodegen and N4jsClientCodegen; avoids NPEs with schemas that include negative enums (e.g., TypeScriptAxios test).

^{Written for commit 48f464a. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 2 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/N4jsClientCodegen.java">

<violation number="1" location="modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/N4jsClientCodegen.java:598">
P2: Skipping null numeric enum values can leave `stringValues` empty, causing `enumValuesToEnumTypeUnion` to return an empty string and generate an invalid/empty enum type when all values are null. Add a fallback when the list is empty.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[Chrimle]

Logging could be costly. The API should either allow nulls, or disallow them.
So, either:

• Add null to the list
• Fail the validation (Illegal Argument / Bad Request)

[Mattias-Sehlstedt]

This is parsing in the context of generating a client, so it will only occur once. It is not tied to the runtime of an application.

This also aligns with how other client generator handles the issue, where they silently drop it (so an enum entry will be missing the generated enum). This is purely meant to aid in the development experience for those that have "bad locales", so that they will not have unit-tests fail due to it.

[wing328]

FYI @TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02) @davidgamero (2022/03) @mkusaka (2022/04) @joscha (2024/10) @dennisameling (2026/02)