fix: StringToAny to Boolean rejects TRUE/True/T/Y spellings, for issue #7842

core/src/main/java/com/alibaba/fastjson2/function/impl/StringToAny.java

@@ -64,7 +64,12 @@ public Object apply(Object from) {
         }
 
         if (targetClass == boolean.class || targetClass == Boolean.class) {
-            return "true".equals(str);
+            if ("true".equalsIgnoreCase(str)
+                    || "T".equalsIgnoreCase(str)
+                    || "Y".equalsIgnoreCase(str)) {
+                return Boolean.TRUE;
+            }
+            return Boolean.FALSE;
         }
 
         if (targetClass == BigDecimal.class) {

core/src/test/java/com/alibaba/fastjson2/issues_7800/Issue7842.java

@@ -0,0 +1,48 @@
+package com.alibaba.fastjson2.issues_7800;
+
+import com.alibaba.fastjson2.util.TypeUtils;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@Tag("regression")
+public class Issue7842 {
+    @Test
+    public void testTrueSpellings() {
+        for (String s : new String[]{"true", "TRUE", "True", "T", "t", "Y", "y"}) {
+            assertTrue(TypeUtils.cast(s, Boolean.class), s);
+        }
+    }
+
+    @Test
+    public void testFalseSpellings() {
+        for (String s : new String[]{"false", "FALSE", "False", "0", "F", "f", "N", "n"}) {
+            assertFalse(TypeUtils.cast(s, Boolean.class), s);
+        }
+    }
+
+    @Test
+    public void testLenientFallback() {
+        assertFalse(TypeUtils.cast("abc", Boolean.class));
+        assertFalse(TypeUtils.cast("2", Boolean.class));
+        assertFalse(TypeUtils.cast("YES", Boolean.class));
+        // "1" stays false: pinned by JSONObjectTest.test_invoke, do not change it here
+        assertFalse(TypeUtils.cast("1", Boolean.class));
+        assertNull(TypeUtils.cast("", Boolean.class));
+        assertNull(TypeUtils.cast("null", Boolean.class));
+        assertNull(TypeUtils.cast(null, Boolean.class));
+    }
+
+    @Test
+    public void testPrimitive() {
+        assertEquals(Boolean.TRUE, TypeUtils.cast("TRUE", boolean.class));
+        assertEquals(Boolean.FALSE, TypeUtils.cast("1", boolean.class));
+        assertEquals(Boolean.FALSE, TypeUtils.cast("FALSE", boolean.class));
+        assertEquals(Boolean.FALSE, TypeUtils.cast("abc", boolean.class));
+        assertEquals(Boolean.FALSE, TypeUtils.cast("", boolean.class));
+    }
+}