Don't unnecessarily keep a type and a classifier in Dependency

.gitignore

@@ -1,2 +1,4 @@
 target/
 .bsp/
+.metals/
+.vscode/

interface/src/main/java/coursierapi/Dependency.java

@@ -11,8 +11,6 @@ public final class Dependency implements Serializable {
     private String version;
     private final Set<Map.Entry<String, String>> exclusions;
     private String configuration;
-    private String type;
-    private String classifier;
     private Publication publication;
     private boolean transitive;
 
@@ -22,8 +20,6 @@ private Dependency(Module module, String version) {
         this.version = version;
         this.exclusions = new HashSet<>();
         this.configuration = "";
-        this.type = "";
-        this.classifier = "";
         this.publication = null;
         this.transitive = true;
     }
@@ -76,12 +72,22 @@ public Dependency withConfiguration(String configuration) {
     }
 
     public Dependency withType(String type) {
-        this.type = type;
+        if (publication == null)
+          publication = new Publication("", type, "", "");
+        else
+          publication = publication.withType(type);
+        if (publication.isEmpty())
+          publication = null;
         return this;
     }
 
     public Dependency withClassifier(String classifier) {
-        this.classifier = classifier;
+        if (publication == null)
+          publication = new Publication("", "", "", classifier);
+        else
+          publication = publication.withClassifier(classifier);
+        if (publication.isEmpty())
+          publication = null;
         return this;
     }
 
@@ -105,8 +111,6 @@ public boolean equals(Object obj) {
                     this.version.equals(other.version) &&
                     this.exclusions.equals(other.exclusions) &&
                     this.configuration.equals(other.configuration) &&
-                    this.type.equals(other.type) &&
-                    this.classifier.equals(other.classifier) &&
                     Objects.equals(this.publication, other.publication) &&
                     this.transitive == other.transitive;
         }
@@ -115,7 +119,7 @@ public boolean equals(Object obj) {
 
     @Override
     public int hashCode() {
-        return 37 * (37 * (37 * (37 * (37 * (37 * (37 * (17 + module.hashCode()) + version.hashCode()) + exclusions.hashCode()) + configuration.hashCode()) + type.hashCode()) + classifier.hashCode()) + Objects.hashCode(publication)) + Boolean.hashCode(transitive);
+        return 37 * (37 * (37 * (37 * (37 * (17 + module.hashCode()) + version.hashCode()) + exclusions.hashCode()) + configuration.hashCode()) + Objects.hashCode(publication)) + Boolean.hashCode(transitive);
     }
 
     @Override
@@ -136,14 +140,6 @@ public String toString() {
             b.append(", configuration=");
             b.append(configuration);
         }
-        if (!type.isEmpty()) {
-            b.append(", type=");
-            b.append(type);
-        }
-        if (!classifier.isEmpty()) {
-            b.append(", classifier=");
-            b.append(classifier);
-        }
         if (publication != null) {
             b.append(", publication=");
             b.append(publication);
@@ -173,11 +169,13 @@ public String getConfiguration() {
     }
 
     public String getType() {
-        return type;
+        if (publication == null) return "";
+        return publication.getType();
     }
 
     public String getClassifier() {
-        return classifier;
+        if (publication == null) return "";
+        return publication.getClassifier();
     }
 
     public Publication getPublication() {

interface/src/main/java/coursierapi/Publication.java

@@ -44,6 +44,26 @@ public String getClassifier() {
         return classifier;
     }
 
+    public Publication withName(String updatedName) {
+        return new Publication(updatedName, this.type, this.extension, this.classifier);
+    }
+
+    public Publication withType(String updatedType) {
+        return new Publication(this.name, updatedType, this.extension, this.classifier);
+    }
+
+    public Publication withExtension(String updatedExtension) {
+        return new Publication(this.name, this.type, updatedExtension, this.classifier);
+    }
+
+    public Publication withClassifier(String updatedClassifier) {
+        return new Publication(this.name, this.type, this.extension, updatedClassifier);
+    }
+
+    public boolean isEmpty() {
+        return name.isEmpty() && type.isEmpty() && extension.isEmpty() && classifier.isEmpty();
+    }
+
     @Override
     public boolean equals(Object o) {
         if (this == o)

interface/src/main/scala/coursier/internal/api/ApiHelper.scala

@@ -112,13 +112,10 @@ object ApiHelper {
       .map(e => (Organization(e.getKey), ModuleName(e.getValue)))
       .toSet
     val configuration = Configuration(dep.getConfiguration)
-    val tpe = Type(dep.getType)
-    val classifier = Classifier(dep.getClassifier)
 
     val dep0 = Dependency(module0, dep.getVersion)
       .withExclusions(exclusions)
       .withConfiguration(configuration)
-      .withAttributes(Attributes(tpe, classifier))
       .withTransitive(dep.isTransitive)
 
     Option(dep.getPublication)