Merge pull request #4083 from abyss638:issue-4082-unnecessaryimport-nested-classes

[java] UnnecessaryImport false positive for on-demand imports of nested classes (fix for #4082) #4083

.all-contributorsrc

@@ -6768,6 +6768,15 @@
         "code",
         "financial"
       ]
+    },
+    {
+      "login": "abyss638",
+      "name": "Simon Abykov",
+      "avatar_url": "https://avatars.githubusercontent.com/u/90252673?v=4",
+      "profile": "https://github.com/abyss638",
+      "contributions": [
+        "code"
+      ]
     }
   ],
   "contributorsPerLine": 7,

docs/pages/release_notes.md

@@ -16,9 +16,14 @@ This is a {{ site.pmd.release_type }} release.
 
 ### Fixed Issues
 
+* java-codestyle
+    * [#4082](https://github.com/pmd/pmd/issues/4082): \[java] UnnecessaryImport false positive for on-demand imports of nested classes
+
 ### API Changes
 
 ### External Contributions
 
+* [#4083](https://github.com/pmd/pmd/pull/4083): \[java] UnnecessaryImport false positive for on-demand imports of nested classes (fix for #4082) - [@abyss638](https://github.com/abyss638)
+
 {% endtocmaker %}
 

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/rule/codestyle/UnnecessaryImportRule.java

@@ -210,6 +210,20 @@ public class UnnecessaryImportRule extends AbstractJavaRule {
             }
         }
 
+        // check on-demand imports for inner classes
+        it = imports.iterator();
+        while (it.hasNext()) {
+            ImportWrapper i = it.next();
+            if (!i.isStaticOnDemand() && i.isOnDemand()) {
+                String possibleClassName = i.getFullName() + "$" + candName;
+                Class<?> possibleClazz = referenceNode.getRoot().getClassTypeResolver()
+                        .loadClassOrNull(possibleClassName);
+                if (possibleClazz != null) {
+                    it.remove();
+                }
+            }
+        }
+
         // check static on-demand imports
         it = imports.iterator();
         while (it.hasNext()) {
@@ -220,6 +234,20 @@ public class UnnecessaryImportRule extends AbstractJavaRule {
             }
         }
 
+        // check static on-demand imports for static inner classes
+        it = imports.iterator();
+        while (it.hasNext()) {
+            ImportWrapper i = it.next();
+            if (i.isStaticOnDemand()) {
+                String possibleClassName = i.getFullName() + "$" + candName;
+                Class<?> possibleClazz = referenceNode.getRoot().getClassTypeResolver()
+                        .loadClassOrNull(possibleClassName);
+                if (possibleClazz != null) {
+                    it.remove();
+                }
+            }
+        }
+
         if (referenceNode instanceof TypeNode && ((TypeNode) referenceNode).getType() != null) {
             Class<?> c = ((TypeNode) referenceNode).getType();
             if (c.getPackage() != null) {

pmd-java/src/test/java/net/sourceforge/pmd/lang/java/rule/codestyle/unnecessaryimport/package2/C.java

@@ -7,5 +7,9 @@ package net.sourceforge.pmd.lang.java.rule.codestyle.unnecessaryimport.package2;
 public class C {
     private C() { }
 
+    public class IC { }
+
+    public static class ISC { }
+
     public static final String V = "";
 }

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/rule/codestyle/xml/UnnecessaryImport.xml

@@ -916,6 +916,34 @@ public class U {
         ]]></code>
     </test-code>
 
+    <test-code>
+        <description>[java] UnnecessaryImport false positive for on-demand imports of non-static nested classes</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+package net.sourceforge.pmd.lang.java.rule.codestyle.unnecessaryimport.package1;
+
+import net.sourceforge.pmd.lang.java.rule.codestyle.unnecessaryimport.package2.C.*; // SUPPRESS CHECKSTYLE needed for test case
+
+public class U {
+    IC c;
+}
+        ]]></code>
+    </test-code>
+
+    <test-code>
+        <description>[java] UnnecessaryImport false positive for static on-demand imports of static nested classes</description>
+        <expected-problems>0</expected-problems>
+        <code><![CDATA[
+package net.sourceforge.pmd.lang.java.rule.codestyle.unnecessaryimport.package1;
+
+import static net.sourceforge.pmd.lang.java.rule.codestyle.unnecessaryimport.package2.C.*; // SUPPRESS CHECKSTYLE needed for test case
+
+public class U {
+    ISC sc;
+}
+        ]]></code>
+    </test-code>
+
     <test-code>
         <description>Necessary imports for @snippet tags introduced with JEP 413 in Java 18</description>
         <expected-problems>0</expected-problems>