Fix concurrent serialization test for StoredScript (elastic#82278)

This fixes the concurrent toXContent tests for `StoredScript`. It turns
out that `StoredScript`'s tests are the only tests to encode a very long
string and `SMILE`'s xcontent serialization has unpredictable behavior
for long strings. It'll always produce a valid encoding, but sometimes
long strings will be output with the marker for utf-8 instead of ascii.
That causes the bytes comparison that the concurrent serialization
tests. So we never test with SMILE here. That's ok. The test is mostly
about concurrency, not xcontent type.

Also! The error message was quite difficult to debug here. So I improved
it while I was there.

Closes elastic#82257

Author: nik9000

server/src/main/java/org/elasticsearch/script/StoredScriptSource.java

@@ -17,7 +17,6 @@
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
-import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.xcontent.LoggingDeprecationHandler;
 import org.elasticsearch.xcontent.NamedXContentRegistry;
 import org.elasticsearch.xcontent.ObjectParser;
@@ -43,12 +42,6 @@
  * saved in the {@link ClusterState}.
  */
 public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> implements Writeable, ToXContentObject {
-
-    /**
-     * Standard deprecation logger for used to deprecate allowance of empty templates.
-     */
-    private static final DeprecationLogger deprecationLogger = DeprecationLogger.getLogger(StoredScriptSource.class);
-
     /**
      * Standard {@link ParseField} for outer level of stored script source.
      */

test/framework/src/main/java/org/elasticsearch/test/AbstractSerializingTestCase.java

@@ -16,6 +16,8 @@
 import org.elasticsearch.xcontent.XContentBuilder;
 import org.elasticsearch.xcontent.XContentParser;
 import org.elasticsearch.xcontent.XContentType;
+import org.elasticsearch.xcontent.cbor.CborXContent;
+import org.elasticsearch.xcontent.smile.SmileXContent;
 
 import java.io.IOException;
 import java.time.Instant;
@@ -53,7 +55,16 @@ public final void testFromXContent() throws IOException {
      * concurrently.
      */
     public final void testConcurrentToXContent() throws IOException, InterruptedException, ExecutionException {
-        XContentType xContentType = randomFrom(XContentType.values());
+        XContentType xContentType = randomValueOtherThanMany(
+            /*
+             * SMILE will sometimes use the unicode marker for ascii strings
+             * if the it's internal buffer doeesn't have enough space for the
+             * whole string. That's fine for SMILE readers, but we're comparing
+             * bytes here so we can't use it.
+             */
+            type -> type.xContent() == SmileXContent.smileXContent,
+            () -> randomFrom(XContentType.values())
+        );
         T testInstance = createXContextTestInstance(xContentType);
         ToXContent.Params params = new ToXContent.DelegatingMapParams(
             singletonMap(RestSearchAction.TYPED_KEYS_PARAM, "true"),
@@ -71,7 +82,20 @@ public final void testConcurrentToXContent() throws IOException, InterruptedExce
         concurrentTest(() -> {
             try {
                 for (int r = 0; r < rounds; r++) {
-                    assertEquals(firstTimeBytes, toXContent(testInstance, xContentType, params, humanReadable).toBytesRef());
+                    BytesRef thisRoundBytes = toXContent(testInstance, xContentType, params, humanReadable).toBytesRef();
+                    if (firstTimeBytes.bytesEquals(thisRoundBytes)) {
+                        continue;
+                    }
+                    StringBuilder error = new StringBuilder("Failed to round trip over ");
+                    if (humanReadable) {
+                        error.append("human readable ");
+                    }
+                    error.append(xContentType);
+                    error.append("\nCanonical is:\n").append(Strings.toString(testInstance, true, true));
+                    boolean showBytes = xContentType.xContent() == CborXContent.cborXContent;
+                    error.append("\nWanted : ").append(showBytes ? firstTimeBytes : firstTimeBytes.utf8ToString());
+                    error.append("\nBut got: ").append(showBytes ? thisRoundBytes : thisRoundBytes.utf8ToString());
+                    fail(error.toString());
                 }
             } catch (IOException e) {
                 throw new AssertionError(e);