Fix ArXiVIdentifier -- dot is required and not arbitrary character

CHANGELOG.md

@@ -35,6 +35,7 @@ Note that this project **does not** adhere to [Semantic Versioning](http://semve
 - The metadata-to-pdf actions now also embeds the bibfile to the PDF. [#8037](https://github.com/JabRef/jabref/pull/8037)
 - The snap was updated to use the core20 base and to use lzo compression for better startup performance [#8109](https://github.com/JabRef/jabref/pull/8109)
 - We improved the Drag and Drop behavior in the "Customize Entry Types" Dialog [#6338](https://github.com/JabRef/jabref/issues/6338)
+- When determing the URL of an ArXiV eprint, the URL now points to the version [#8149](https://github.com/JabRef/jabref/pull/8149)
 
 ### Fixed
 

src/main/java/org/jabref/gui/desktop/JabRefDesktop.java

@@ -26,8 +26,8 @@
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.field.Field;
 import org.jabref.model.entry.field.StandardField;
+import org.jabref.model.entry.identifier.ArXivIdentifier;
 import org.jabref.model.entry.identifier.DOI;
-import org.jabref.model.entry.identifier.Eprint;
 import org.jabref.model.util.FileHelper;
 import org.jabref.preferences.PreferencesService;
 
@@ -84,7 +84,12 @@ public static void openExternalViewer(BibDatabaseContext databaseContext,
             openDoi(link);
             return;
         } else if (StandardField.EPRINT.equals(field)) {
-            link = Eprint.build(link).map(Eprint::getURIAsASCIIString).orElse(link);
+            link = ArXivIdentifier.parse(link)
+                                  .map(ArXivIdentifier::getExternalURI)
+                                  .filter(Optional::isPresent)
+                                  .map(Optional::get)
+                                  .map(URI::toASCIIString)
+                                  .orElse(link);
             // should be opened in browser
             field = StandardField.URL;
         }

src/main/java/org/jabref/logic/importer/util/IdentifierParser.java

@@ -5,8 +5,8 @@
 
 import org.jabref.model.entry.field.Field;
 import org.jabref.model.entry.field.StandardField;
+import org.jabref.model.entry.identifier.ArXivIdentifier;
 import org.jabref.model.entry.identifier.DOI;
-import org.jabref.model.entry.identifier.Eprint;
 import org.jabref.model.entry.identifier.ISBN;
 import org.jabref.model.entry.identifier.Identifier;
 import org.jabref.model.entry.identifier.MathSciNetId;
@@ -28,7 +28,7 @@ private static Function<String, Optional<? extends Identifier>> getParserForFiel
         } else if (StandardField.ISBN.equals(field)) {
             return ISBN::parse;
         } else if (StandardField.EPRINT.equals(field)) {
-            return Eprint::build;
+            return ArXivIdentifier::parse;
         } else if (StandardField.MR_NUMBER.equals(field)) {
             return MathSciNetId::parse;
         }

src/main/java/org/jabref/model/entry/identifier/ArXivIdentifier.java

@@ -37,36 +37,34 @@ public class ArXivIdentifier implements Identifier {
 
     public static Optional<ArXivIdentifier> parse(String value) {
         String identifier = value.replaceAll(" ", "");
-        Pattern identifierPattern = Pattern.compile("(" + ARXIV_PREFIX + ")?\\s?:?\\s?(?<id>\\d{4}.\\d{4,5})(v(?<version>\\d+))?\\s?(\\[(?<classification>\\S+)\\])?");
+        Pattern identifierPattern = Pattern.compile("(" + ARXIV_PREFIX + ")?\\s?:?\\s?(?<id>\\d{4}\\.\\d{4,5})(v(?<version>\\d+))?\\s?(\\[(?<classification>\\S+)\\])?");
         Matcher identifierMatcher = identifierPattern.matcher(identifier);
         if (identifierMatcher.matches()) {
-            String id = identifierMatcher.group("id");
-            String classification = identifierMatcher.group("classification");
-            if (classification == null) {
-                classification = "";
-            }
-            String version = identifierMatcher.group("version");
-            if (version == null) {
-                version = "";
-            }
-            return Optional.of(new ArXivIdentifier(id, version, classification));
+            return getArXivIdentifier(identifierMatcher);
         }
 
         Pattern oldIdentifierPattern = Pattern.compile("(" + ARXIV_PREFIX + ")?\\s?:?\\s?(?<id>(?<classification>[a-z\\-]+(\\.[A-Z]{2})?)/\\d{7})(v(?<version>\\d+))?");
         Matcher oldIdentifierMatcher = oldIdentifierPattern.matcher(identifier);
         if (oldIdentifierMatcher.matches()) {
-            String id = oldIdentifierMatcher.group("id");
-            String classification = oldIdentifierMatcher.group("classification");
-            String version = oldIdentifierMatcher.group("version");
-            if (version == null) {
-                version = "";
-            }
-            return Optional.of(new ArXivIdentifier(id, version, classification));
+            return getArXivIdentifier(oldIdentifierMatcher);
         }
 
         return Optional.empty();
     }
 
+    private static Optional<ArXivIdentifier> getArXivIdentifier(Matcher matcher) {
+        String id = matcher.group("id");
+        String classification = matcher.group("classification");
+        if (classification == null) {
+            classification = "";
+        }
+        String version = matcher.group("version");
+        if (version == null) {
+            version = "";
+        }
+        return Optional.of(new ArXivIdentifier(id, version, classification));
+    }
+
     public Optional<String> getClassification() {
         if (classification.isEmpty()) {
             return Optional.empty();
@@ -123,7 +121,7 @@ public String getNormalizedWithoutVersion() {
     @Override
     public Optional<URI> getExternalURI() {
         try {
-            return Optional.of(new URI("https://arxiv.org/abs/" + identifier));
+            return Optional.of(new URI("https://arxiv.org/abs/" + getNormalized()));
         } catch (URISyntaxException e) {
             return Optional.empty();
         }

src/test/java/org/jabref/model/entry/identifier/ArXivIdentifierTest.java

@@ -1,5 +1,6 @@
 package org.jabref.model.entry.identifier;
 
+import java.net.URI;
 import java.util.Optional;
 
 import org.junit.jupiter.api.Test;
@@ -50,6 +51,18 @@ void parseOldIdentifier() throws Exception {
         assertEquals(Optional.of(new ArXivIdentifier("math.GT/0309136", "math.GT")), parsed);
     }
 
+    @Test
+    public void acceptLegacyEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("astro-ph.GT/1234567");
+        assertEquals(Optional.of(new ArXivIdentifier("astro-ph.GT/1234567", "astro-ph.GT")), parsed);
+    }
+
+    @Test
+    public void acceptLegacyMathEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("math/1234567");
+        assertEquals(Optional.of(new ArXivIdentifier("math/1234567", "math")), parsed);
+    }
+
     @Test
     void parseOldIdentifierWithArXivPrefix() throws Exception {
         Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("arXiv:math.GT/0309136");
@@ -91,4 +104,71 @@ void parseOldUrlWithVersion() throws Exception {
 
         assertEquals(Optional.of(new ArXivIdentifier("hep-ex/0307015", "1", "hep-ex")), parsed);
     }
+
+    @Test
+    void fourDigitDateIsInvalidInLegacyFormat() throws Exception {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("2017/1118");
+        assertEquals(Optional.empty(), parsed);
+    }
+
+    @Test
+    public void acceptPlainEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("0706.0001");
+        assertEquals(Optional.of(new ArXivIdentifier("0706.0001")), parsed);
+    }
+
+    @Test
+    public void acceptPlainEprintWithVersion() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("0706.0001v1");
+        assertEquals(Optional.of(new ArXivIdentifier("0706.0001", "v1", "")), parsed);
+    }
+
+    @Test
+    public void acceptArxivPrefix() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("arXiv:0706.0001v1");
+        assertEquals(Optional.of(new ArXivIdentifier("0706.0001", "v1", "")), parsed);
+    }
+
+    @Test
+    public void ignoreLeadingAndTrailingWhitespaces() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("  0706.0001v1 ");
+        assertEquals(Optional.of(new ArXivIdentifier("0706.0001", "v1", "")), parsed);
+    }
+
+    @Test
+    public void rejectEmbeddedEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("other stuff 0706.0001v1 end");
+        assertEquals(Optional.empty(), parsed);
+    }
+
+    @Test
+    public void rejectInvalidEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("https://thisisnouri");
+        assertEquals(Optional.empty(), parsed);
+    }
+
+    @Test
+    public void acceptUrlHttpEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("http://arxiv.org/abs/0706.0001v1");
+        assertEquals(Optional.of(new ArXivIdentifier("0706.0001", "v1", "")), parsed);
+    }
+
+    @Test
+    public void acceptUrlHttpsEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("https://arxiv.org/abs/0706.0001v1");
+        assertEquals(Optional.of(new ArXivIdentifier("0706.0001", "v1", "")), parsed);
+    }
+
+    @Test
+    public void rejectUrlOtherDomainEprint() {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("https://asdf.org/abs/0706.0001v1");
+        assertEquals(Optional.empty(), parsed);
+    }
+
+    @Test
+    public void constructCorrectURLForEprint() throws Exception {
+        Optional<ArXivIdentifier> parsed = ArXivIdentifier.parse("0706.0001v1");
+        assertEquals(Optional.of(new URI("https://arxiv.org/abs/0706.0001v1")), parsed.get().getExternalURI());
+    }
+
 }