Fix month checker regex by ridsch · Pull Request #15678 · JabRef/jabref

ridsch · 2026-05-04T22:39:22Z

Related issues and pull requests

PR Description

This PR updates the MonthChecker validation logic by adding start (^) and end ($) anchors to the underlying regular expressions. This change enforces exact string matching for month values, ensuring that only valid integers (1-12) or normalized BibTeX strings are accepted while preventing malformed partial matches from passing the validation layer.

Steps to test

Open JabRef and create a new entry (e.g., an Article).
Locate a field that utilizes the Month validator (such as the Month field in the entry editor or the String Editor).
Enter a value that contains a valid month name but is incorrectly formatted (January123 or #jan#invalid).
Observe that the validator now correctly flags these as errors.
Enter a valid month (10 or #jan#) and verify it is still accepted.

AI Disclosure

I utilized Google Gemini to help troubleshoot local Gradle build environment issues and assist in drafting JUnit test structure for this PR. All logic was manually verified and tested against the JabRef contribution guidelines.

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 · 2026-05-04T22:39:36Z

Review Summary by Qodo

Add regex anchors to enforce exact month validation

🐞 Bug fix

Walkthroughs

Description

• Add regex anchors (^ and $) to MonthChecker patterns
• Enforce exact string matching for month validation
• Prevent malformed partial matches from passing validation
• Update CHANGELOG.md documenting the fix

Diagram

flowchart LR
  A["MonthChecker Regex Patterns"] -->|Add anchors ^ and $| B["Exact String Matching"]
  B -->|Reject| C["Partial Matches"]
  B -->|Accept| D["Valid Months"]

File Changes

1. jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java 🐞 Bug fix +2/-2

Add regex anchors for exact month matching

• Updated ONLY_AN_INTEGER regex pattern from [1-9]|10|11|12 to ^([1-9]|10|11|12)$
• Updated MONTH_NORMALIZED regex pattern to include start and end anchors
• Enforces exact matching for month values (1-12 or normalized BibTeX strings)
• Prevents validation bypass through malformed partial matches like "January123"

jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java

2. CHANGELOG.md 📝 Documentation +1/-0

Document MonthChecker validation fix

• Added entry documenting the MonthChecker fix for issue #15577
• Describes the fix as preventing partial matches for month values

CHANGELOG.md

qodo-free-for-open-source-projects · 2026-05-04T22:39:37Z

Code Review by Qodo

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

1. ~~Missing partial month tests~~ ✓ Resolved 📎 Requirement gap ≡ Correctness

Description

Month validation behavior was changed, but no regression tests were added to ensure mixed/partial
values like 1abc or #jan# trailing are rejected. This risks reintroducing the original bug
without automated detection.

Code

jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[R16-20]

+    private static final Predicate<String> ONLY_AN_INTEGER = Pattern.compile("^([1-9]|10|11|12)$")
                                                             .asPredicate();
private static final Predicate<String> MONTH_NORMALIZED = Pattern
-            .compile("#jan#|#feb#|#mar#|#apr#|#may#|#jun#|#jul#|#aug#|#sep#|#oct#|#nov#|#dec#")
+            .compile("^(#jan#|#feb#|#mar#|#apr#|#may#|#jun#|#jul#|#aug#|#sep#|#oct#|#nov#|#dec#)$")
     .asPredicate();

Evidence
The checklist requires adding/adjusting unit tests for the previously accepted invalid inputs. The
production code was modified to tighten regex matching, but the existing MonthCheckerTest does not
include assertions for the required regression cases (e.g., 1abc, #jan# trailing).
Add regression tests to reject mixed/partial month values in MonthChecker
AGENTS.md
AGENTS.md
jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[16-20]
jablib/src/test/java/org/jabref/logic/integrity/MonthCheckerTest.java[31-84]

Agent prompt

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

## Issue description
`MonthChecker` behavior was tightened, but regression tests for the originally reported partial/mixed inputs are missing.
## Issue Context
Compliance requires tests that fail for values that previously passed due to partial regex matching (e.g., `1abc`, `#jan# trailing`).
## Fix Focus Areas
- jablib/src/test/java/org/jabref/logic/integrity/MonthCheckerTest.java[31-84]

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

2. ~~Rejects zero-padded months~~ ✓ Resolved 🐞 Bug ≡ Correctness

Description

In BibLaTeX mode, MonthChecker now rejects month integers with a leading zero (e.g.,
"01"/"02"/"09"), returning “should be an integer or normalized”. The codebase already parses and
produces these values, so integrity checks/validation can start flagging existing entries as invalid
after this change.

Code

jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[R16-17]

+    private static final Predicate<String> ONLY_AN_INTEGER = Pattern.compile("^([1-9]|10|11|12)$")
                                                             .asPredicate();

Evidence
MonthChecker validates BibLaTeX months using ONLY_AN_INTEGER.test(value.trim()), and the new
pattern only matches 1–12 without a leading zero. However, Month.parse explicitly documents
support for “Single and Double Digit months … (01 to 12)”, and tests/importers construct entries
with zero-padded month strings like "02" and "09"; these will now fail MonthChecker in BibLaTeX
mode.
jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[16-48]
jablib/src/main/java/org/jabref/model/entry/Month.java[64-97]
jablib/src/test/java/org/jabref/logic/importer/fetcher/ResearchGateTest.java[87-121]
jablib/src/test/java/org/jabref/logic/importer/fileformat/BibtexParserTest.java[2185-2205]
jablib/src/main/java/org/jabref/logic/integrity/FieldCheckers.java[45-47]

Agent prompt

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

## Issue description
`MonthChecker`'s BibLaTeX integer validation regex only matches `1`–`12` without a leading zero. This causes values like `"01"`, `"02"`, `"09"` (which the codebase parses/produces) to be treated as invalid.
### Issue Context
`Month.parse` explicitly supports “01 to 12”, and multiple tests construct entries with `StandardField.MONTH` set to zero-padded values.
### Fix Focus Areas
- jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[16-20]
### Suggested change
- Update the integer regex to accept an optional leading zero for 1–9, e.g.:
- `^(0?[1-9]|1[0-2])$`
- Add/extend unit tests (e.g., `MonthCheckerTest`) to cover:
- Accept: `01`, `02`, `09`, `10`, `12`
- Reject: `00`, `13`, `01abc`, `#jan# trailing`

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

3. ~~Changelog uses internal classname~~ ✓ Resolved 📘 Rule violation ⚙ Maintainability

Description

The new CHANGELOG entry references the internal class name MonthChecker and deviates from the
surrounding end-user-focused phrasing style. This reduces readability and consistency for end users.

Code

CHANGELOG.md[107]

+- Fixed issue where MonthChecker allowed partial matches for month values. [#15577](https://github.com/JabRef/jabref/pull/15675)

Evidence

The checklist requires CHANGELOG entries to be end-user focused and professionally
worded/consistent. The added bullet explicitly mentions an internal validator class name rather than
describing the user-visible effect in user terms.

AGENTS.md
CHANGELOG.md[107-107]
Best Practice: Learned patterns

Agent prompt

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

## Issue description
CHANGELOG entry is a bit too implementation-specific and inconsistent in style.
## Issue Context
Nearby entries use end-user phrasing (e.g., "We fixed...") and generally avoid internal class names.
## Fix Focus Areas
- CHANGELOG.md[107-107]

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

4. Predicate intent unclear 🐞 Bug ⚙ Maintainability

Description

MonthChecker still uses Pattern.asPredicate() for validation, so full-string matching
correctness relies on regex anchors rather than the predicate’s match semantics. This makes the
intent less explicit and increases the chance of a future regression if the pattern is edited.

Code

jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[R16-20]

+    private static final Predicate<String> ONLY_AN_INTEGER = Pattern.compile("^([1-9]|10|11|12)$")
                                                             .asPredicate();
private static final Predicate<String> MONTH_NORMALIZED = Pattern
-            .compile("#jan#|#feb#|#mar#|#apr#|#may#|#jun#|#jul#|#aug#|#sep#|#oct#|#nov#|#dec#")
+            .compile("^(#jan#|#feb#|#mar#|#apr#|#may#|#jun#|#jul#|#aug#|#sep#|#oct#|#nov#|#dec#)$")
     .asPredicate();

Evidence

Both month validators are built using .asPredicate() even though the surrounding logic is doing
strict whole-field validation (as shown by the anchors and value.trim() usage). Elsewhere, strict
month-format checks are implemented using full-string matching (String.matches(...)), which is
more self-documenting for this use case.

jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[16-49]
jablib/src/main/java/org/jabref/model/entry/Month.java[191-205]

Agent prompt

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

## Issue description
`MonthChecker` uses `Pattern.asPredicate()` for validations that are intended to be whole-string matches.
### Issue Context
The current behavior is correct only because the regexes are anchored. Using `asMatchPredicate()` encodes the intent (“entire string must match”) directly.
### Fix Focus Areas
- jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java[16-20]
### Suggested change
- Replace `.asPredicate()` with `.asMatchPredicate()`.
- Optionally drop the `^...$` anchors once using `asMatchPredicate()` (or keep them, but avoid relying on them for semantics).

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

pluto-han · 2026-05-05T11:40:54Z

Please address Qodo comments

subhramit · 2026-05-05T17:36:12Z

If possible, please also add a test.

…abref into fix-month-checker-regex

ridsch · 2026-05-05T18:16:10Z

updated the regex to allow zero-padded months (01-09) as suggested by Qodo and added regression tests in MonthCheckerTest.java

pluto-han · 2026-05-05T20:21:49Z

+
+    @Test
+    void checkValueAcceptsZeroPaddedMonths() {
+        // Confirms that the optional zero (0?) in the regex works for Biblatex mode


Remove these comments.

pluto-han · 2026-05-05T20:25:03Z

+
+    @Test
+    void checkValueDoesNotAcceptPartialMatches() {
+        assertEquals(Optional.of(Localization.lang("should be an integer or normalized")),


Revert the format change

Localization.lang is not necessary

pluto-han · 2026-05-05T20:25:49Z

Please disclose AI uasge in this PR.

ridsch · 2026-05-06T00:47:56Z

Added AI Disclosure to PR description.

pluto-han · 2026-05-06T12:01:56Z

LGTM

* upstream/main: (21 commits) chore(deps): update dependency com.konghq:unirest-modules-gson to v4.10.0 (JabRef#15715) Add manual tests (JabRef#15351) Refactored the comments for UnlinkedFilesCrawler (JabRef#15709) Replace inline styles with CSS classes (JabRef#15694) add test case for multiple authors in csl citaiton (JabRef#15707) fix invalid desktop file for linux (JabRef#15702) Change FileKeystore and Folder fields to disable/enable (JabRef#15685) Chore(deps): Bump org.openrewrite.recipe:rewrite-recipe-bom from 3.30.0 to 3.30.1 (JabRef#15696) New Crowdin updates (JabRef#15693) Chore(deps): Bump dev.langchain4j:langchain4j-bom in /versions (JabRef#15698) Chore(deps): Bump org.apache.logging.log4j:log4j-to-slf4j in /versions (JabRef#15700) chore(deps): update dependency org.apache.logging.log4j:log4j-to-slf4j to v2.26.0 (JabRef#15699) Chore(deps): Bump org.openrewrite.rewrite from 7.32.1 to 7.32.2 (JabRef#15697) Chore(deps): Bump jablib/src/main/resources/csl-locales (JabRef#15689) Fix month checker regex (JabRef#15678) Chore(deps): Bump com.dlsc.gemsfx:gemsfx in /versions (JabRef#15692) Chore(deps): Bump org.hisp.dhis:json-tree in /versions (JabRef#15691) Chore(deps): Bump jablib/src/main/resources/csl-styles (JabRef#15690) New Crowdin updates (JabRef#15687) Chore(deps): Bump com.konghq:unirest-java-core in /versions (JabRef#15683) ...

Ridenour, Schuyler D and others added 3 commits May 4, 2026 15:33

Fix JabRef#15577: Add regex anchors to enforce exact month matching

c0184fb

Merge branch 'JabRef:main' into fix-month-checker-regex

8642f48

docs: update changelog for JabRef#15577

5c2cec1

qodo-free-for-open-source-projects Bot reviewed May 4, 2026

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Comment thread jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java Outdated

Comment thread jablib/src/main/java/org/jabref/logic/integrity/MonthChecker.java Outdated

github-actions Bot added the status: changes-required Pull requests that are not yet complete label May 4, 2026

github-actions Bot mentioned this pull request May 4, 2026

Bug: MonthChecker Uses Partial Regex Match — Invalid Month Values Pass Validation #15577

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pluto-han reviewed May 5, 2026

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Comment thread CHANGELOG.md Outdated

Update CHANGELOG.md

7da5f4a

github-actions Bot added status: no-bot-comments and removed status: changes-required Pull requests that are not yet complete labels May 5, 2026

ridsch and others added 3 commits May 5, 2026 12:58

Merge branch 'JabRef:main' into fix-month-checker-regex

9211737

Allow zero-padded months and add regression tests

68a5c54

Merge branch 'fix-month-checker-regex' of https://github.com/ridsch/j…

a966af8

…abref into fix-month-checker-regex

github-actions Bot added status: changes-required Pull requests that are not yet complete and removed status: no-bot-comments labels May 5, 2026

pluto-han reviewed May 5, 2026

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Comment thread jablib/src/test/java/org/jabref/logic/integrity/MonthCheckerTest.java Outdated

Use checkerBiblatex as requested by the maintainer

66a5d45

github-actions Bot added status: no-bot-comments and removed status: changes-required Pull requests that are not yet complete labels May 5, 2026

pluto-han reviewed May 5, 2026

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reverted format and removed Localization.lang

75b98f1

Merge branch 'main' into fix-month-checker-regex

ad65567

Siedlerchr approved these changes May 6, 2026

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Siedlerchr added this pull request to the merge queue May 6, 2026

github-actions Bot added the status: to-be-merged PRs which are accepted and should go into the merge-queue. label May 6, 2026

Merged via the queue into JabRef:main with commit e0c3f92 May 6, 2026
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Review Summary by Qodo

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File Changes

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