Fix String.endsWith for overlapping regex matches (#1880)

pkl-core/src/main/java/org/pkl/core/stdlib/base/StringNodes.java

@@ -333,14 +333,13 @@ public final class StringNodes {
 
     @TruffleBoundary
     @Specialization
-    // inefficient but at least correct
     protected boolean eval(String self, VmRegex regex) {
-      var matcher = regex.matcher(self);
-      var end = -1;
-      while (matcher.find()) {
-        end = matcher.end();
+      // try every suffix; `find()` would skip matches that overlap an earlier one
+      var matcher = regex.matcher(self).useTransparentBounds(true).useAnchoringBounds(false);
+      for (var start = self.length(); ; start = self.offsetByCodePoints(start, -1)) {
+        if (matcher.region(start, self.length()).matches()) return true;
+        if (start == 0) return false;
       }
-      return end == self.length();
     }
   }
 

pkl-core/src/test/files/LanguageSnippetTests/input/api/string.pkl

@@ -76,7 +76,12 @@ facts {
   ["endsWith()"] {
     str1.endsWith("")
     str1.endsWith("efg")
+    str1.endsWith(Regex(#"\w"#))
+    "aaa".endsWith(Regex("aa"))
     !str1.endsWith("efx")
+    !str1.endsWith(Regex(#"\d"#))
+    !str1.endsWith(Regex(#"\bfg"#))
+    !str1.endsWith(Regex("^fg"))
   }
 
   ["isRegex"] {

pkl-core/src/test/files/LanguageSnippetTests/output/api/string.pcf

@@ -59,6 +59,11 @@ facts {
     true
     true
     true
+    true
+    true
+    true
+    true
+    true
   }
   ["isRegex"] {
     true