Update AbstractXContentParser to support parsers that don't provide text characters (elastic#129005) (elastic#129058)

(cherry picked from commit 5ee6dfa)

Author: Mikep86

docs/changelog/129005.yaml

@@ -0,0 +1,6 @@
+pr: 129005
+summary: Update AbstractXContentParser to support parsers that don't provide text
+  characters
+area: Infra/Core
+type: bug
+issues: []

libs/x-content/src/main/java/org/elasticsearch/xcontent/support/AbstractXContentParser.java

@@ -87,7 +87,13 @@ void ensureNumberConversion(boolean coerce, long result, Class<? extends Number>
     public boolean isBooleanValue() throws IOException {
         return switch (currentToken()) {
             case VALUE_BOOLEAN -> true;
-            case VALUE_STRING -> Booleans.isBoolean(textCharacters(), textOffset(), textLength());
+            case VALUE_STRING -> {
+                if (hasTextCharacters()) {
+                    yield Booleans.isBoolean(textCharacters(), textOffset(), textLength());
+                } else {
+                    yield Booleans.isBoolean(text());
+                }
+            }
             default -> false;
         };
     }
@@ -96,7 +102,11 @@ public boolean isBooleanValue() throws IOException {
     public boolean booleanValue() throws IOException {
         Token token = currentToken();
         if (token == Token.VALUE_STRING) {
-            return Booleans.parseBoolean(textCharacters(), textOffset(), textLength(), false /* irrelevant */);
+            if (hasTextCharacters()) {
+                return Booleans.parseBoolean(textCharacters(), textOffset(), textLength(), false /* irrelevant */);
+            } else {
+                return Booleans.parseBoolean(text(), false /* irrelevant */);
+            }
         }
         return doBooleanValue();
     }

libs/x-content/src/test/java/org/elasticsearch/xcontent/MapXContentParserTests.java

@@ -97,6 +97,40 @@ public void testCopyCurrentStructure() throws IOException {
         }
     }
 
+    public void testParseBooleanStringValue() throws IOException {
+        try (
+            XContentParser parser = new MapXContentParser(
+                xContentRegistry(),
+                LoggingDeprecationHandler.INSTANCE,
+                Map.of("bool_key", "true"),
+                randomFrom(XContentType.values())
+            )
+        ) {
+            assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
+            assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
+            assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
+            assertTrue(parser.isBooleanValue());
+            assertTrue(parser.booleanValue());
+            assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
+        }
+
+        try (
+            XContentParser parser = new MapXContentParser(
+                xContentRegistry(),
+                LoggingDeprecationHandler.INSTANCE,
+                Map.of("bool_key", "false"),
+                randomFrom(XContentType.values())
+            )
+        ) {
+            assertEquals(XContentParser.Token.START_OBJECT, parser.nextToken());
+            assertEquals(XContentParser.Token.FIELD_NAME, parser.nextToken());
+            assertEquals(XContentParser.Token.VALUE_STRING, parser.nextToken());
+            assertTrue(parser.isBooleanValue());
+            assertFalse(parser.booleanValue());
+            assertEquals(XContentParser.Token.END_OBJECT, parser.nextToken());
+        }
+    }
+
     private void compareTokens(CheckedConsumer<XContentBuilder, IOException> consumer) throws IOException {
         for (XContentType xContentType : EnumSet.allOf(XContentType.class)) {
             logger.info("--> testing with xcontent type: {}", xContentType);