[bugfix] Fix detection of recusive functions in XQuery

Closes eXist-db/exist#5685

Author: adamretter

exist-core/pom.xml

@@ -686,7 +686,9 @@
                                 <include>src/main/java/org/exist/dom/memtree/reference/TextReferenceImpl.java</include>
                                 <include>src/main/java/org/exist/util/ByteOrderMark.java</include>
                                 <include>src/test/java/org/exist/xquery/ImportFromPkgTest.java</include>
+                                <include>src/main/java/org/exist/xquery/UserDefinedFunction.java</include>
                                 <include>src/test/java/org/exist/xquery/WatchdogTest.java</include>
+                                <include>src/main/java/org/exist/xquery/XQueryContext.java</include>
                                 <include>src/test/java/org/exist/xquery/value/DateTimeTypesTest.java</include>
                                 <include>src/test/java/org/exist/xquery/functions/fn/FunXmlToJsonTest.java</include>
                                 <include>src/test/java/org/exist/xquery/functions/fn/ParsingFunctionsTest.java</include>
@@ -855,6 +857,7 @@
                                 <include>src/main/java/org/exist/xslt/XsltURIResolverHelper.java</include>
                                 <include>src/test/resources/org/exist/validation/catalog.xml</include>
                                 <include>src/test/resources/standalone-webapp/WEB-INF/web.xml</include>
+                                <include>src/test/xquery/maps/maps.xqm</include>
                                 <include>src/test/xquery/util/util.xml</include>
                                 <include>src/test/xquery/xquery3/serialize.xql</include>
                             </includes>
@@ -997,7 +1000,9 @@
                                 <exclude>src/main/java/org/exist/xqj/Marshaller.java</exclude>
                                 <exclude>src/test/java/org/exist/xquery/ImportFromPkgTest.java</exclude>
                                 <exclude>src/main/java/org/exist/xquery/NameTest.java</exclude>
+                                <exclude>src/main/java/org/exist/xquery/UserDefinedFunction.java</exclude>
                                 <exclude>src/test/java/org/exist/xquery/WatchdogTest.java</exclude>
+                                <exclude>src/main/java/org/exist/xquery/XQueryContext.java</exclude>
                                 <exclude>src/main/java/org/exist/xquery/functions/fn/FunUriCollection.java</exclude>
                                 <exclude>src/main/java/org/exist/xquery/functions/fn/FunXmlToJson.java</exclude>
                                 <exclude>src/test/java/org/exist/xquery/functions/fn/FunXmlToJsonTest.java</exclude>
@@ -1043,6 +1048,7 @@
                                 <exclude>src/main/java/org/exist/xslt/XsltURIResolverHelper.java</exclude>
                                 <exclude>src/test/resources/org/exist/validation/catalog.xml</exclude>
                                 <exclude>src/test/resources/standalone-webapp/WEB-INF/web.xml</exclude>
+                                <exclude>src/test/xquery/maps/maps.xqm</exclude>
                                 <exclude>src/test/xquery/util/util.xml</exclude>
                                 <exclude>src/main/java/org/exist/resolver/ResolverFactory.java</exclude>
                                 <exclude>src/main/java/org/exist/resolver/XercesXmlResolverAdapter.java</exclude>

exist-core/src/main/java/org/exist/xquery/UserDefinedFunction.java

@@ -1,4 +1,28 @@
 /*
+ * Elemental
+ * Copyright (C) 2024, Evolved Binary Ltd
+ *
+ * [email protected]
+ * https://www.evolvedbinary.com | https://www.elemental.xyz
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; version 2.1.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * NOTE: Parts of this file contain code from 'The eXist-db Authors'.
+ *       The original license header is included below.
+ *
+ * =====================================================================
+ *
  * eXist-db Open Source Native XML Database
  * Copyright (C) 2001 The eXist-db Authors
  *
@@ -185,21 +209,25 @@ public void dump(ExpressionDumper dumper) {
         dumper.display(signature.getReturnType().toString());
     }
 
-    /* (non-Javadoc)
-     * @see java.lang.Object#toString()
-     */
+    @Override
     public String toString() {
         final FunctionSignature signature = getSignature();
         final StringBuilder buf = new StringBuilder();
-        if (signature.getName() != null)
-        	{buf.append(signature.getName());}
+        if (signature.getName() != null) {
+			buf.append(signature.getName());
+		}
         buf.append('(');
-        for(int i = 0; i < signature.getArgumentTypes().length; i++) {
-			if(i > 0)
-				{buf.append(", ");}
+        for (int i = 0; i < signature.getArgumentTypes().length; i++) {
+			if (i > 0) {
+				buf.append(", ");
+			}
+			buf.append('$');
+			buf.append(getParameters().get(i));
+			buf.append(" as ");
 			buf.append(signature.getArgumentTypes()[i]);
 		}
-        buf.append(')');
+        buf.append(") as ");
+		buf.append(signature.getReturnType());
         return buf.toString();
     }
 

exist-core/src/main/java/org/exist/xquery/XQueryContext.java

@@ -1,4 +1,28 @@
 /*
+ * Elemental
+ * Copyright (C) 2024, Evolved Binary Ltd
+ *
+ * [email protected]
+ * https://www.evolvedbinary.com | https://www.elemental.xyz
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; version 2.1.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * NOTE: Parts of this file contain code from 'The eXist-db Authors'.
+ *       The original license header is included below.
+ *
+ * =====================================================================
+ *
  * eXist-db Open Source Native XML Database
  * Copyright (C) 2001 The eXist-db Authors
  *
@@ -2513,7 +2537,13 @@ public void functionEnd() {
 
     @Override
     public boolean tailRecursiveCall(final FunctionSignature signature) {
-        return callStack.contains(signature);
+        // NOTE(AR) this should be improved further... eXist-db lacked any sort of proper escape analysis!
+        for (final FunctionSignature existingFunctionSignature : callStack) {
+            if (existingFunctionSignature == signature) {
+                return true;
+            }
+        }
+        return false;
     }
 
     @Override

exist-core/src/test/xquery/maps/maps.xqm

@@ -1,4 +1,28 @@
 (:
+ : Elemental
+ : Copyright (C) 2024, Evolved Binary Ltd
+ :
+ : [email protected]
+ : https://www.evolvedbinary.com | https://www.elemental.xyz
+ :
+ : This library is free software; you can redistribute it and/or
+ : modify it under the terms of the GNU Lesser General Public
+ : License as published by the Free Software Foundation; version 2.1.
+ :
+ : This library is distributed in the hope that it will be useful,
+ : but WITHOUT ANY WARRANTY; without even the implied warranty of
+ : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ : Lesser General Public License for more details.
+ :
+ : You should have received a copy of the GNU Lesser General Public
+ : License along with this library; if not, write to the Free Software
+ : Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ :
+ : NOTE: Parts of this file contain code from 'The eXist-db Authors'.
+ :       The original license header is included below.
+ :
+ : =====================================================================
+ :
  : eXist-db Open Source Native XML Database
  : Copyright (C) 2001 The eXist-db Authors
  :
@@ -51,6 +75,14 @@ declare variable $mt:integerKeys := map {
 
 declare variable $mt:mapOfSequences := map {0: (), 1 : ("One", "Two") };
 
+declare variable $mt:nested-places := map {
+      "Italia": map {
+          "Piemonte": map {
+              "Bardonecchia": 1
+          }
+      }
+};
+
 declare
     %test:assertEquals("Wednesday")
 function mt:createLiteral1() {
@@ -188,6 +220,37 @@ function mt:for-each2() {
         $nm?b
 };
 
+declare
+    %test:assertEquals("<country>Italia<region>Piemonte</region></country>")
+function mt:for-each3() {
+    map:for-each($mt:nested-places, function($country-key, $region-map) {
+        <country>{
+            $country-key,
+                map:for-each($region-map, function($region-key, $town-map) {
+                    <region>{$region-key}</region>
+                })
+        }</country>
+    })
+};
+
+declare
+    %test:assertEquals("<country>Italia<region>Piemonte<town>Bardonecchia</town></region></country>")
+function mt:for-each4() {
+    map:for-each($mt:nested-places, function($country-key, $region-map) {
+        <country>{
+            $country-key,
+                map:for-each($region-map, function($region-key, $town-map) {
+                    <region>{
+                        $region-key,
+                          map:for-each($town-map, function($town-key, $town-value) {
+                              <town>{$town-key}</town>
+                          })
+                    }</region>
+                })
+        }</country>
+    })
+};
+
 declare
     %test:assertEquals("Sunday")
 function mt:createWithSingleKey() {