[DEFECT] New Edit Content: locale version creation crashes with 500 when using a language-only locale (no country)

[adrianjm-dotCMS]

Problem Statement

In the new Edit Content experience, attempting to create a new content version for a language-only locale (one configured with just a language, no country code) results in a 500 Internal Server Error from the backend. The UI surfaces this as a generic "Unknown Error", giving the user no actionable information.

The failure is confirmed in the network layer: POST /api/v1/content/versions/{id} returns:

{"message":"null value in entry: country=null"}

This indicates the backend builds a key/entry using both language and country, but does not handle the case where country is null — a valid state since dotCMS allows locales to be defined with language alone.

Impact: Any content type with the new Edit Content enabled that has a language-only locale is affected. Users cannot create locale versions for those languages until the bug is fixed.

Screen.Recording.2026-06-10.at.3.10.09.PM.mov

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Steps to Reproduce

1. Ensure a language-only locale exists (e.g., es — Spanish, no country).
2. Navigate to any content type with the new Edit Content experience enabled.
3. Open a content item.
4. In the locale/language selector, attempt to add a new content in the language-only locale.
5. Observe the result.

Expected: The new locale version is created successfully (same as when using a locale with both language and country, e.g., es_MX).

Actual: The UI shows "Unknown Error" and the API returns HTTP 500 with {"message":"null value in entry: country=null"}.

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Acceptance Criteria

• Creating a locale version with a language-only locale (no country code) in the new Edit Content experience succeeds without errors.
• POST /api/v1/content/versions?identifier={id} handles a null country value gracefully — no 500 is thrown.
• The UI does not show "Unknown Error" for language-only locales.
• Creating locale versions with locales that include both language and country continues to work (no regression).

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dotCMS Version

Latest from main branch.

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Severity

Medium - Some functionality impacted

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Links

NA

[github-actions]

PRs linked to this issue

• fix(content): handle language-only locales without a country code by @jcastro-dotcms