JSON parse failures should be 4xx codes (elastic#112703)

It seemed if there wasn't any text to parse, this is not an internal
issue but instead an argument issue.

I simply changed the exception thrown. If we don't agree with this, I
can adjust `query` parsing directly, but this seemed like the better
choice.

closes: elastic#112296

docs/changelog/112703.yaml

@@ -0,0 +1,5 @@
+pr: 112703
+summary: JSON parse failures should be 4xx codes
+area: Infra/Core
+type: bug
+issues: []

libs/x-content/impl/src/main/java/org/elasticsearch/xcontent/provider/json/JsonXContentParser.java

@@ -111,7 +111,7 @@ public String text() throws IOException {
     }
 
     private void throwOnNoText() {
-        throw new IllegalStateException("Can't get text on a " + currentToken() + " at " + getTokenLocation());
+        throw new IllegalArgumentException("Expected text at " + getTokenLocation() + " but found " + currentToken());
     }
 
     @Override

server/src/main/java/org/elasticsearch/index/mapper/IpFieldMapper.java

@@ -42,7 +42,6 @@
 import org.elasticsearch.search.aggregations.support.CoreValuesSourceType;
 import org.elasticsearch.search.lookup.FieldValues;
 import org.elasticsearch.search.lookup.SearchLookup;
-import org.elasticsearch.xcontent.XContentParser;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -533,8 +532,9 @@ protected String contentType() {
     @Override
     protected void parseCreateField(DocumentParserContext context) throws IOException {
         InetAddress address;
+        String value = context.parser().textOrNull();
         try {
-            address = value(context.parser(), nullValue);
+            address = value == null ? nullValue : InetAddresses.forString(value);
         } catch (IllegalArgumentException e) {
             if (ignoreMalformed) {
                 context.addIgnoredField(fieldType().name());
@@ -552,14 +552,6 @@ protected void parseCreateField(DocumentParserContext context) throws IOExceptio
         }
     }
 
-    private static InetAddress value(XContentParser parser, InetAddress nullValue) throws IOException {
-        String value = parser.textOrNull();
-        if (value == null) {
-            return nullValue;
-        }
-        return InetAddresses.forString(value);
-    }
-
     private void indexValue(DocumentParserContext context, InetAddress address) {
         if (dimension) {
             context.getDimensions().addIp(fieldType().name(), address).validate(context.indexSettings());

server/src/test/java/org/elasticsearch/common/ReferenceDocsTests.java

@@ -66,7 +66,7 @@ public void testResourceValidation() throws Exception {
             builder.startObject("UNEXPECTED").endObject().endObject();
 
             try (var stream = BytesReference.bytes(builder).streamInput()) {
-                expectThrows(IllegalStateException.class, () -> ReferenceDocs.readLinksBySymbol(stream));
+                expectThrows(IllegalArgumentException.class, () -> ReferenceDocs.readLinksBySymbol(stream));
             }
         }
 

server/src/test/java/org/elasticsearch/index/query/MatchQueryBuilderTests.java

@@ -373,7 +373,7 @@ public void testParseFailsWithTermsArray() {
                 "message1" : ["term1", "term2"]
               }
             }""";
-        expectThrows(IllegalStateException.class, () -> parseQuery(json2));
+        expectThrows(IllegalArgumentException.class, () -> parseQuery(json2));
     }
 
     public void testExceptionUsingAnalyzerOnNumericField() {