Don't report journal name as abbreviated when full name = abbreviated name

CHANGELOG.md

@@ -31,6 +31,7 @@ We refer to [GitHub issues](https://github.com/JabRef/jabref/issues) by using `#
 - We fixed an issue where in rare cases entries where overlayed in the main table. https://github.com/JabRef/jabref/issues/3281
 - We fixed an issue where selecting a group messed up the focus of the main table / entry editor. https://github.com/JabRef/jabref/issues/3367
 - We fixed an issue where composite author names were sorted incorrectly. https://github.com/JabRef/jabref/issues/2828
+- We fixed an issue where some journal names were wrongly marked as abbreviated. [#4115](https://github.com/JabRef/jabref/issues/4115)
 - We fixed an issue where the custom file column were sorted incorrectly. https://github.com/JabRef/jabref/issues/3119
 - We fixed an issues where the entry losses focus when a field is edited and at the same time used for sorting. https://github.com/JabRef/jabref/issues/3373
 - We fixed an issue where the menu on Mac OS was not displayed in the usual Mac-specific way. https://github.com/JabRef/jabref/issues/3146

src/main/java/org/jabref/logic/journals/JournalAbbreviationRepository.java

@@ -27,18 +27,28 @@ private static boolean isMatched(String name, Abbreviation abbreviation) {
     }
 
     private static boolean isMatchedAbbreviated(String name, Abbreviation abbreviation) {
-        return name.equalsIgnoreCase(abbreviation.getIsoAbbreviation())
+        boolean isAbbreviated = name.equalsIgnoreCase(abbreviation.getIsoAbbreviation())
                 || name.equalsIgnoreCase(abbreviation.getMedlineAbbreviation());
+        boolean isExpanded = name.equalsIgnoreCase(abbreviation.getName());
+        return isAbbreviated && !isExpanded;
     }
 
     public int size() {
         return abbreviations.size();
     }
 
+    /**
+     * Returns true if the given journal name is contained in the list either in its full form (e.g Physical Review
+     * Letters) or its abbreviated form (e.g. Phys. Rev. Lett.).
+     */
     public boolean isKnownName(String journalName) {
         return abbreviations.stream().anyMatch(abbreviation -> isMatched(journalName.trim(), abbreviation));
     }
 
+    /**
+     * Returns true if the given journal name is in its abbreviated form (e.g. Phys. Rev. Lett.). The test is strict,
+     * i.e. journals whose abbreviation is the same as the full name are not considered
+     */
     public boolean isAbbreviatedName(String journalName) {
         return abbreviations.stream().anyMatch(abbreviation -> isMatchedAbbreviated(journalName.trim(), abbreviation));
     }

src/test/java/org/jabref/logic/integrity/AbbreviationCheckerTest.java

@@ -0,0 +1,35 @@
+package org.jabref.logic.integrity;
+
+import java.util.Optional;
+
+import org.jabref.logic.journals.Abbreviation;
+import org.jabref.logic.journals.JournalAbbreviationRepository;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
+
+class AbbreviationCheckerTest {
+
+    private JournalAbbreviationRepository abbreviationRepository;
+    private AbbreviationChecker checker;
+
+    @BeforeEach
+    void setUp() {
+        abbreviationRepository = new JournalAbbreviationRepository(new Abbreviation("Test Journal", "T. J."));
+        checker = new AbbreviationChecker(abbreviationRepository);
+    }
+
+    @Test
+    void checkValueComplainsAboutAbbreviatedJournalName() {
+        assertNotEquals(Optional.empty(), checker.checkValue("T. J."));
+    }
+
+    @Test
+    void checkValueDoesNotComplainAboutJournalNameThatHasSameAbbreviation() {
+        abbreviationRepository.addEntry(new Abbreviation("Journal", "Journal"));
+        assertEquals(Optional.empty(), checker.checkValue("Journal"));
+    }
+}