[bugfix] fn:replace, fn:tokenize, and fn:analyze-string must throw FORX0003 when pattern matches an empty string

Closes #3803

Author: adamretter

exist-core/src/main/java/org/exist/xquery/functions/fn/FunAnalyzeString.java

@@ -130,6 +130,9 @@ private void analyzeString(final MemTreeBuilder builder, final String input, Str
 
         try {
             final RegularExpression regularExpression = config.compileRegularExpression(pattern, flags, "XP30", warnings);
+            if (regularExpression.matches("")) {
+                throw new XPathException(this, ErrorCodes.FORX0003, "regular expression could match empty string");
+            }
 
             //TODO(AR) cache the regular expression... might be possible through Saxon config
 

exist-core/src/main/java/org/exist/xquery/functions/fn/FunReplace.java

@@ -120,6 +120,9 @@ public Sequence eval(final Sequence[] args, final Sequence contextSequence) thro
 
 			try {
 				final RegularExpression regularExpression = config.compileRegularExpression(pattern, flags, "XP30", warnings);
+				if (regularExpression.matches("")) {
+					throw new XPathException(this, ErrorCodes.FORX0003, "regular expression could match empty string");
+				}
 
 				//TODO(AR) cache the regular expression... might be possible through Saxon config
 

exist-core/src/test/xquery/regex.xml

@@ -137,6 +137,12 @@
         <expected>lo</expected>
     </test>
 
+    <test output="text">
+        <task>fn:replace-regex-match-empty-1</task>
+        <code>fn:replace("12.34" , "^\D*", "")</code>
+        <error>FORX0003</error>
+    </test>
+
     <test output="text">
         <task>fn:tokenize-qflag-1</task>
         <code>fn:tokenize("12.3.5.6", ".", "q")</code>
@@ -155,4 +161,16 @@
         <error>XPTY0004</error>
     </test>
 
+    <test output="text">
+        <task>fn:tokenize-regex-match-empty-1</task>
+        <code>fn:tokenize("12.34" , "^\D*")</code>
+        <error>FORX0003</error>
+    </test>
+
+    <test output="text">
+        <task>fn:analyze-string-regex-match-empty-1</task>
+        <code>fn:analyze-string("12.34" , "^\D*")</code>
+        <error>FORX0003</error>
+    </test>
+
 </TestSet>