WW-5770 Make struts.convention.result.path scopable per package

core/src/main/java/org/apache/struts2/config/ScopedConstantProvider.java

@@ -18,8 +18,10 @@
  */
 package org.apache.struts2.config;
 
+import org.apache.struts2.config.entities.PackageConfig;
+
 /**
- * Resolves a scopable constant for the current action invocation: the package's {@code <scoped-constant>}, inherited
+ * Resolves a scopable constant for the current action invocation or a given package: the package's {@code <scoped-constant>}, inherited
  * through {@code extends}, or else the global constant.
  *
  * @since 7.5.0
@@ -32,4 +34,18 @@ public interface ScopedConstantProvider {
      * @throws IllegalArgumentException when {@code name} is not scopable
      */
     String getValue(String name);
+
+    /**
+     * @param name          a constant registered through a {@link ScopableConstants} bean
+     * @param packageConfig the package whose scoped constants, inherited ones included, take precedence; may be
+     *                      {@code null}
+     * @return the package's scoped value, or else {@link #getValue(String)}
+     * @throws IllegalArgumentException when {@code name} is not scopable; this default checks only on the
+     *                                  {@link #getValue(String)} fallback, as package values were validated at startup
+     * @since 7.5.0
+     */
+    default String getValue(String name, PackageConfig packageConfig) {
+        String value = packageConfig != null ? packageConfig.getAllScopedConstants().get(name) : null;
+        return value != null ? value : getValue(name);
+    }
 }

core/src/main/java/org/apache/struts2/config/providers/StrutsScopedConstantProvider.java

@@ -49,13 +49,29 @@ public void setContainer(Container container) {
 
     @Override
     public String getValue(String name) {
+        requireScopable(name);
+        return resolve(name, currentPackage().orElse(null));
+    }
+
+    @Override
+    public String getValue(String name, PackageConfig packageConfig) {
+        if (packageConfig == null) {
+            return getValue(name);
+        }
+        requireScopable(name);
+        return resolve(name, packageConfig);
+    }
+
+    private void requireScopable(String name) {
         if (!scopableNames.contains(name)) {
             throw new IllegalArgumentException(String.format(
                     "Constant [%s] is not scopable; register it through a %s bean", name, ScopableConstants.class.getName()));
         }
-        return currentPackage()
-                .map(packageConfig -> packageConfig.getAllScopedConstants().get(name))
-                .orElseGet(() -> container.getInstance(String.class, name));
+    }
+
+    private String resolve(String name, PackageConfig packageConfig) {
+        String value = packageConfig != null ? packageConfig.getAllScopedConstants().get(name) : null;
+        return value != null ? value : container.getInstance(String.class, name);
     }
 
     private Optional<PackageConfig> currentPackage() {

core/src/test/java/org/apache/struts2/config/providers/StrutsScopedConstantProviderTest.java

@@ -24,6 +24,7 @@
 import org.apache.struts2.config.ScopedConstantProvider;
 import org.apache.struts2.config.StrutsXmlConfigurationProvider;
 import org.apache.struts2.config.entities.ActionConfig;
+import org.apache.struts2.config.entities.PackageConfig;
 import org.apache.struts2.mock.MockActionInvocation;
 import org.apache.struts2.mock.MockActionProxy;
 
@@ -121,6 +122,52 @@ public void testGlobalConstantUntouchedByScopedRead() {
         assertEquals("global", container.getInstance(String.class, "sample.scopable"));
     }
 
+    public void testExplicitPackageResolvesInheritedValue() {
+        assertEquals("base", provider.getValue("sample.scopable", configuration.getPackageConfig("child")));
+    }
+
+    public void testExplicitPackageWinsOverInvocationPackage() {
+        enterPackage("override");
+
+        assertEquals("base", provider.getValue("sample.scopable", configuration.getPackageConfig("child")));
+    }
+
+    public void testExplicitPackageWithoutOverrideIgnoresInvocationPackage() {
+        enterPackage("override");
+
+        assertEquals("global", provider.getValue("sample.scopable", configuration.getPackageConfig("plain")));
+    }
+
+    public void testExplicitPackageWithoutOverrideGivesGlobalOutsideInvocation() {
+        assertEquals("global", provider.getValue("sample.scopable", configuration.getPackageConfig("plain")));
+    }
+
+    public void testNullPackageFallsBackToInvocation() {
+        enterPackage("override");
+
+        assertEquals("override", provider.getValue("sample.scopable", null));
+    }
+
+    public void testExplicitPackageEmptyOverrideIsReturnedAsIs() {
+        assertEquals("", provider.getValue("sample.scopable", configuration.getPackageConfig("empty")));
+    }
+
+    public void testExplicitPackageRejectsUnregisteredName() {
+        PackageConfig plain = configuration.getPackageConfig("plain");
+
+        assertThatThrownBy(() -> provider.getValue("sample.unknown", plain))
+                .isInstanceOf(IllegalArgumentException.class)
+                .hasMessageContaining("[sample.unknown]");
+    }
+
+    public void testLambdaProviderGetsPackageLookup() {
+        ScopedConstantProvider lambda = name -> "fallback";
+
+        assertEquals("base", lambda.getValue("sample.scopable", configuration.getPackageConfig("child")));
+        assertEquals("fallback", lambda.getValue("sample.scopable", configuration.getPackageConfig("plain")));
+        assertEquals("fallback", lambda.getValue("sample.scopable", null));
+    }
+
     private void enterPackage(String packageName) {
         MockActionProxy proxy = new MockActionProxy();
         proxy.setConfig(new ActionConfig.Builder(packageName, "test", ActionSupport.class.getName()).build());