Fix: Prevent creating empty or duplicate fields by pluto-han · Pull Request #15168 · JabRef/jabref

pluto-han · 2026-02-19T17:13:31Z

Related issues and pull requests

PR Description

This PR addresses the issue where empty and duplicate fields can be created. When checking duplication, use equalsIgnoreCase instead of equals. After creating a new field, it will scroll to and highlight newly added field.

Required verification screenshot:

Steps to test

Open File -> Preference -> Entry types
Select an entry type, type some spaces or a string with spaces (e.g. "te st") or leave field empty. Click "+" or press enter.
Expected result: No fields are created, JabRef warns users "Fields cannot be empty and must not contain spaces."
Type "test" and save. Then type "test" again, click "+" or press enter.
Expected result: A pop-up warning shows up: You added field "test" twice. Only one will be kept.

Checklist

I own the copyright of the code submitted and I license it under the MIT license
I manually tested my changes in running JabRef (always required)
I added JUnit tests for changes (if applicable)
I added screenshots in the PR description (if change is visible to the user)
I added a screenshot in the PR description showing a library with a single entry with me as author and as title the issue number
I described the change in CHANGELOG.md in a way that can be understood by the average user (if change is visible to the user)
I checked the user documentation for up to dateness and submitted a pull request to our user documentation repository

qodo-free-for-open-source-projects · 2026-02-19T17:13:54Z

Review Summary by Qodo

Prevent empty, duplicate, and invalid field creation in custom entry types

🐞 Bug fix

Walkthroughs

Description

• Prevent creation of empty fields and fields containing spaces with validation
• Prevent duplicate field creation using case-insensitive comparison
• Capitalize first letter of custom field names in display
• Scroll to and highlight newly added fields in the UI

File Changes

1. jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/CustomEntryTypesTab.java ✨ Enhancement +9/-2

Add field validation and scroll to new fields
• Changed addNewField action handler to call local method instead of viewModel method
• Added validation check before adding new field
• Modified addNewField() method to handle Optional return and scroll to newly added field
jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/CustomEntryTypesTab.java

2. jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/CustomEntryTypesTabViewModel.java 🐞 Bug fix +14/-9

Implement duplicate field detection and return newly added field
• Changed addNewField() return type from void to Optional<FieldViewModel>
• Updated field validation error message to match entry type validation message
• Modified duplicate field detection to use case-insensitive comparison with equalsIgnoreCase()
• Return empty Optional when duplicate field detected, otherwise return the newly created field
jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/CustomEntryTypesTabViewModel.java

3. jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/FieldViewModel.java 🐞 Bug fix +1/-1

Normalize field name casing to lowercase
• Convert field name to lowercase before parsing to ensure consistent casing
jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/FieldViewModel.java

View more (5)

4. jablib/src/main/java/org/jabref/model/entry/field/FieldTextMapper.java ✨ Enhancement +1/-1

Capitalize first letter of custom field display names
• Apply capitalizeFirst() to all unknown field names in display name generation
jablib/src/main/java/org/jabref/model/entry/field/FieldTextMapper.java

5. jablib/src/test/java/org/jabref/logic/quality/consistency/BibliographyConsistencyCheckResultCsvWriterTest.java 🧪 Tests +1/-1

Update test for capitalized field names
• Updated test expectation to reflect capitalized custom field name
jablib/src/test/java/org/jabref/logic/quality/consistency/BibliographyConsistencyCheckResultCsvWriterTest.java

6. jablib/src/test/java/org/jabref/logic/quality/consistency/BibliographyConsistencyCheckResultTxtWriterTest.java 🧪 Tests +2/-2

Update tests for capitalized field names
• Updated two test expectations to reflect capitalized custom field name in output
jablib/src/test/java/org/jabref/logic/quality/consistency/BibliographyConsistencyCheckResultTxtWriterTest.java

7. CHANGELOG.md 📝 Documentation +2/-0

Document field validation fixes

• Added two entries documenting fixes for duplicate field creation and empty/space-containing fields

CHANGELOG.md

8. jablib/src/main/resources/l10n/JabRef_en.properties 📝 Documentation +1/-1

Update field validation error message
• Updated field validation error message to include "must not contain spaces" clause
jablib/src/main/resources/l10n/JabRef_en.properties

qodo-free-for-open-source-projects · 2026-02-19T17:19:57Z

Code Review by Qodo

🐞 Bugs (1) 📘 Rule violations (1) 📎 Requirement gaps (0)

✅ 1. toLowerCase() missing Locale.ROOT 📘 Rule violation ✓ Correctness

Description

FieldViewModel.toField uses String.toLowerCase() without specifying Locale.ROOT, which can
produce incorrect field names under certain default locales (e.g., Turkish locale casing rules).
This is inconsistent with JabRef code quality conventions and can cause non-deterministic behavior
across environments.

Code

jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/FieldViewModel.java[63]
+        Field field = FieldFactory.parseField(type, displayName.getValue().toLowerCase());

Evidence

PR Compliance ID 6 requires adherence to JabRef style/quality guidance; using default-locale case
conversion is a known Java pitfall and can lead to incorrect results depending on user/system
locale. The changed line introduces default-locale lowercasing in toField.

AGENTS.md
jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/FieldViewModel.java[60-66]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`FieldViewModel.toField` lowercases `displayName` using `toLowerCase()` without an explicit locale, which can yield incorrect results under some system locales.
## Issue Context
JabRef generally uses locale-stable casing conversions (e.g., `Locale.ROOT`) for deterministic behavior across environments.
## Fix Focus Areas
- jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/FieldViewModel.java[60-66]

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

✅ 2. ~~Global title-casing blast radius~~ 🐞 Bug ✓ Correctness

Description

FieldTextMapper.getDisplayName now applies StringUtil.capitalizeFirst broadly, which changes
user-visible labels and export/report headers across the app (not just the custom-entry-type UI) and
also forces the remainder of the name to lowercase (potentially mangling acronyms/camelCase for
non-standard fields).

Code

jablib/src/main/java/org/jabref/model/entry/field/FieldTextMapper.java[R36-40]

          return "Citationkey";
      }
-        return field.getName();
+        return StringUtil.capitalizeFirst(field.getName());
  }

Evidence
The PR changes FieldTextMapper to call StringUtil.capitalizeFirst(...) for most fields.
capitalizeFirst uppercases the first character and lowercases the rest, which is a behavior change
for any consumer of FieldTextMapper. FieldTextMapper is used widely in UI and export/report code, so
this change affects many surfaces beyond the custom entry type editor.
jablib/src/main/java/org/jabref/model/entry/field/FieldTextMapper.java[10-40]
jablib/src/main/java/org/jabref/logic/util/strings/StringUtil.java[658-666]
jabgui/src/main/java/org/jabref/gui/fieldeditors/FieldNameLabel.java[14-20]
jablib/src/main/java/org/jabref/logic/exporter/OOCalcDatabase.java[144-155]
jablib/src/main/java/org/jabref/logic/quality/consistency/BibliographyConsistencyCheckResultWriter.java[83-89]

Agent prompt

The issue below was found during a code review. Follow the provided context and guidance below and implement a solution

## Issue description
`FieldTextMapper.getDisplayName` now title-cases field names via `StringUtil.capitalizeFirst`, which also lowercases the remainder of the string. Because `FieldTextMapper` is used across the UI and exports/reports, this is a broad user-visible behavior change (and may mangle acronyms/camelCase for unknown/internal fields).
### Issue Context
The PR description focuses on preventing empty/duplicate custom fields and capitalizing the first letter for each new field. Applying `capitalizeFirst` in `FieldTextMapper` impacts many unrelated components.
### Fix Focus Areas
- jablib/src/main/java/org/jabref/model/entry/field/FieldTextMapper.java[10-40]
- jablib/src/main/java/org/jabref/logic/util/strings/StringUtil.java[658-666]
- jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/CustomEntryTypesTabViewModel.java[155-177]
- jabgui/src/main/java/org/jabref/gui/preferences/customentrytypes/FieldViewModel.java[26-34]
### Possible fixes
- Option A (scoped): Revert global change in `FieldTextMapper`, and instead capitalize only when adding custom fields in `CustomEntryTypesTabViewModel` / `FieldViewModel` (e.g., transform the user input or the `FieldViewModel.displayName`).
- Option B (preserve remainder): Introduce a helper that uppercases only the first character but leaves the rest unchanged, and use that for display names where appropriate.
- Option C (hybrid): Keep title-casing for standard fields only, but leave `UnknownField` display names as-is (or only uppercase first char without lowercasing rest) to avoid mangling user-defined casing.

ⓘ Copy this prompt and use it to remediate the issue with your preferred AI generation tools

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testlens-app · 2026-02-19T17:32:19Z

✅ All tests passed ✅

🏷️ Commit: 6d903ba
▶️ Tests: 11198 executed
⚪️ Checks: 63/63 completed

Learn more about TestLens at testlens.app.

subhramit · 2026-02-20T10:27:06Z


        assertEquals("""
-                entry type,citation key,custom,Pages,Title
+                entry type,citation key,Custom,Pages,Title


Are these changes related and needed?

Yes, now when a field is created, its first letter is capitalized like entry type. If dont change this code, tests will not pass

But fields should always be lowercase !

But fields should always be lowercase !

Got it, i'll fix it now

@koppor Just for clarification: Do we lowercase fields always?

Yes, for standardfields, customizable for custom fields: "Hardcode StandardField names and use exact or customized names otherwise". We have an ADR: https://devdocs.jabref.org/decisions/0049-hardcode-fieldnames.html#decision-outcome

Co-authored-by: Subhramit Basu <subhramit.bb@live.in>

pluto-han · 2026-02-21T23:27:24Z

I checked the error output but it seems not related to the part I modified.

github-actions · 2026-02-23T03:56:08Z

Your pull request conflicts with the target branch.

Please merge with your code. For a step-by-step guide to resolve merge conflicts, see https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/addressing-merge-conflicts/resolving-a-merge-conflict-using-the-command-line.

subhramit

Lgtm

* refs/heads/main: Increase max assignments from 2 to 3 Chore(deps): Bump io.zonky.test:embedded-postgres in /versions (#15213) Chore(deps): Bump jablib/src/main/resources/csl-styles (#15211) New Crowdin updates (#15208) Fix: Prevent creating empty or duplicate fields (#15168) chore(deps): update jackson monorepo to v3.1.0 (#15203) Update KeywordEditor to work with escaping (#14929) Chore(deps): Bump com.dlsc.gemsfx:gemsfx in /versions (#15205) Chore(deps): Bump tools.jackson:jackson-bom in /versions (#15206) Fix: Reset External File Type to default (#15167) docs: fix link formatting in ADR 0012 (#15201)

@subhramit

* Prevent empty fields * Prevent duplicate fields * add CHANGELOG.md * scroll to newly added fields * fix test fails * fix test fails * fix test fails * fix test fails * Apply suggestion from @subhramit Co-authored-by: Subhramit Basu <subhramit.bb@live.in> * custom fields should be lowercase * explicit viewmodel name * update CHANGELOG.md * Apply suggestion from @subhramit --------- Co-authored-by: Subhramit Basu <subhramit.bb@live.in> Co-authored-by: Carl Christian Snethlage <50491877+calixtus@users.noreply.github.com>

@subhramit

* Prevent empty fields * Prevent duplicate fields * add CHANGELOG.md * scroll to newly added fields * fix test fails * fix test fails * fix test fails * fix test fails * Apply suggestion from @subhramit Co-authored-by: Subhramit Basu <subhramit.bb@live.in> * custom fields should be lowercase * explicit viewmodel name * update CHANGELOG.md * Apply suggestion from @subhramit --------- Co-authored-by: Subhramit Basu <subhramit.bb@live.in> Co-authored-by: Carl Christian Snethlage <50491877+calixtus@users.noreply.github.com>

pluto-han and others added 11 commits February 18, 2026 01:20

Prevent empty fields

58e7f6e

Prevent duplicate fields

d9f819c

add CHANGELOG.md

467154e

scroll to newly added fields

21a246f

Merge branch 'main' into fix-for-issue-15130

187a08d

fix test fails

b6441cc

fix test fails

8872b51

fix test fails

175b532

Merge branch 'main' into fix-for-issue-15130

5bc187c

fix test fails

05b1f1e

Merge branch 'JabRef:main' into fix-for-issue-15130

1ce7a99

github-actions Bot added the status: no-bot-comments label Feb 19, 2026

github-actions Bot mentioned this pull request Feb 19, 2026

Entry Types Prefs: Make field duplicate prevention similar to entry type duplicate prevention #15130

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subhramit reviewed Feb 20, 2026

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subhramit reviewed Feb 20, 2026

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pluto-han and others added 3 commits February 20, 2026 17:01

Apply suggestion from @subhramit

4de2615

Co-authored-by: Subhramit Basu <subhramit.bb@live.in>

custom fields should be lowercase

c614952

explicit viewmodel name

e5915ce

github-actions Bot added status: changes-required Pull requests that are not yet complete and removed status: no-bot-comments labels Feb 20, 2026

pluto-han added 3 commits February 20, 2026 22:33

Merge branch 'main' into fix-for-issue-15130

329fc24

Merge branch 'main' into fix-for-issue-15130

c8c6997

update CHANGELOG.md

a97fc9c

Merge branch 'main' into fix-for-issue-15130

2a66e82

github-actions Bot removed the status: changes-required Pull requests that are not yet complete label Feb 23, 2026

github-actions Bot added the status: no-bot-comments label Feb 23, 2026

Merge branch 'main' into fix-for-issue-15130

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github-actions Bot added status: changes-required Pull requests that are not yet complete and removed status: no-bot-comments labels Feb 24, 2026

Merge branch 'main' into fix-for-issue-15130

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github-actions Bot added status: no-bot-comments and removed status: changes-required Pull requests that are not yet complete labels Feb 24, 2026

Merge branch 'main' into fix-for-issue-15130

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subhramit added the status: awaiting-second-review For non-trivial changes label Feb 24, 2026

Siedlerchr added this pull request to the merge queue Feb 24, 2026

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Merged via the queue into JabRef:main with commit 503619e Feb 24, 2026
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PR Description

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qodo-free-for-open-source-projects Bot commented Feb 19, 2026

Review Summary by Qodo

Walkthroughs

File Changes

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Code Review by Qodo

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✅ All tests passed ✅

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