From 27e2558fcf5d2c66e5f19bac7c57758f0febdde2 Mon Sep 17 00:00:00 2001
From: Akash Kumar <116457960+akashchamp@users.noreply.github.com>
Date: Thu, 24 Sep 2026 23:52:15 +0530
Subject: [PATCH] [JXPATH-204] Eagerly evaluate UnionContext before returning
 its value

UnionContext only populates its NodeSet lazily, inside setPosition().
A caller that reads getValue() without first iterating the context
(for example, an extension function invoked with a union expression,
e.g. test:fn(a | b), as one of its arguments) received an empty
NodeSet instead of the union of the operand node-sets.

Override getValue() to force the node set to be built via
getContextNodeList() before delegating to the parent implementation,
per the fix suggested in the JIRA report.

Adds a regression test in ExtensionFunctionTest that invokes a custom
NodeSet-consuming function with a union of two location paths and
asserts the full pointer count is seen.

Generated-by: Claude Sonnet 5 (Claude Code)
---
 .../apache/commons/jxpath/ri/axes/UnionContext.java   | 11 +++++++++++
 .../jxpath/ri/compiler/ExtensionFunctionTest.java     | 11 ++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/apache/commons/jxpath/ri/axes/UnionContext.java b/src/main/java/org/apache/commons/jxpath/ri/axes/UnionContext.java
index 01a371b61..ff7473aa7 100644
--- a/src/main/java/org/apache/commons/jxpath/ri/axes/UnionContext.java
+++ b/src/main/java/org/apache/commons/jxpath/ri/axes/UnionContext.java
@@ -48,6 +48,17 @@ public int getDocumentOrder() {
         return contexts.length > 1 ? 1 : super.getDocumentOrder();
     }
 
+    @Override
+    public Object getValue() {
+        // JXPATH-204: the node set is built lazily inside setPosition(), so
+        // force it to be populated before delegating, otherwise callers that
+        // read the value without first iterating (e.g. an extension
+        // function receiving this context as an argument) see an empty
+        // NodeSet.
+        getContextNodeList();
+        return super.getValue();
+    }
+
     @Override
     public boolean setPosition(final int position) {
         if (!prepared) {
diff --git a/src/test/java/org/apache/commons/jxpath/ri/compiler/ExtensionFunctionTest.java b/src/test/java/org/apache/commons/jxpath/ri/compiler/ExtensionFunctionTest.java
index eb76e767b..3cf2adec3 100644
--- a/src/test/java/org/apache/commons/jxpath/ri/compiler/ExtensionFunctionTest.java
+++ b/src/test/java/org/apache/commons/jxpath/ri/compiler/ExtensionFunctionTest.java
@@ -283,4 +283,13 @@ void testStaticMethodLookupWithExpressionContext() {
         final Function func = functions.getFunction("test", "path", args);
         assertEquals("1", func.invoke(new Context(Integer.valueOf(1)), args), "test:path()");
     }
-}
\ No newline at end of file
+
+    @Test
+    void testUnionOperatorArgument() {
+        // JXPATH-204: UnionContext computes its node list lazily (only inside
+        // setPosition()), so a custom function invoked with a union ('|')
+        // expression as an argument used to see an empty NodeSet instead of
+        // the union's actual nodes.
+        assertXPathValue(context, "test:countPointers(/beans[1] | /beans[2])", Integer.valueOf(2));
+    }
+}