Be lenient when parsing build flavor and type on the wire

server/src/main/java/org/elasticsearch/Build.java

@@ -57,7 +57,7 @@ public String displayName() {
             return displayName;
         }
 
-        public static Flavor fromDisplayName(final String displayName) {
+        public static Flavor fromDisplayName(final String displayName, final boolean strict) {
             switch (displayName) {
                 case "default":
                     return Flavor.DEFAULT;
@@ -66,7 +66,12 @@ public static Flavor fromDisplayName(final String displayName) {
                 case "unknown":
                     return Flavor.UNKNOWN;
                 default:
-                    throw new IllegalStateException("unexpected distribution flavor [" + displayName + "]; your distribution is broken");
+                    if (strict) {
+                        final String message = "unexpected distribution flavor [" + displayName + "]; your distribution is broken";
+                        throw new IllegalStateException(message);
+                    } else {
+                        return Flavor.UNKNOWN;
+                    }
             }
         }
 
@@ -91,7 +96,7 @@ public String displayName() {
             this.displayName = displayName;
         }
 
-        public static Type fromDisplayName(final String displayName) {
+        public static Type fromDisplayName(final String displayName, final boolean strict) {
             switch (displayName) {
                 case "deb":
                     return Type.DEB;
@@ -106,9 +111,14 @@ public static Type fromDisplayName(final String displayName) {
                 case "unknown":
                     return Type.UNKNOWN;
                 default:
-                    throw new IllegalStateException("unexpected distribution type [" + displayName + "]; your distribution is broken");
+                    if (strict) {
+                        throw new IllegalStateException("unexpected distribution type [" + displayName + "]; your distribution is broken");
+                    } else {
+                        return Type.UNKNOWN;
+                    }
             }
         }
+
     }
 
     static {
@@ -119,8 +129,9 @@ public static Type fromDisplayName(final String displayName) {
         final boolean isSnapshot;
         final String version;
 
-        flavor = Flavor.fromDisplayName(System.getProperty("es.distribution.flavor", "unknown"));
-        type = Type.fromDisplayName(System.getProperty("es.distribution.type", "unknown"));
+        // these are parsed at startup, and we require that we are able to recognize the values passed in by the startup scripts
+        flavor = Flavor.fromDisplayName(System.getProperty("es.distribution.flavor", "unknown"), true);
+        type = Type.fromDisplayName(System.getProperty("es.distribution.type", "unknown"), true);
 
         final String esPrefix = "elasticsearch-" + Version.CURRENT;
         final URL url = getElasticsearchCodeSourceLocation();
@@ -214,12 +225,14 @@ public static Build readBuild(StreamInput in) throws IOException {
         final Flavor flavor;
         final Type type;
         if (in.getVersion().onOrAfter(Version.V_6_3_0)) {
-            flavor = Flavor.fromDisplayName(in.readString());
+            // be lenient when reading on the wire, the enumeration values from other versions might be different than what we know
+            flavor = Flavor.fromDisplayName(in.readString(), false);
         } else {
             flavor = Flavor.OSS;
         }
         if (in.getVersion().onOrAfter(Version.V_6_3_0)) {
-            type = Type.fromDisplayName(in.readString());
+            // be lenient when reading on the wire, the enumeration values from other versions might be different than what we know
+            type = Type.fromDisplayName(in.readString(), false);
         } else {
             type = Type.UNKNOWN;
         }

server/src/main/java/org/elasticsearch/action/main/MainResponse.java

@@ -129,8 +129,12 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             final String buildType = (String) value.get("build_type");
             response.build =
                     new Build(
-                            buildFlavor == null ? Build.Flavor.UNKNOWN : Build.Flavor.fromDisplayName(buildFlavor),
-                            buildType == null ? Build.Type.UNKNOWN : Build.Type.fromDisplayName(buildType),
+                            /*
+                             * Be lenient when reading on the wire, the enumeration values from other versions might be different than what
+                             * we know.
+                             */
+                            buildFlavor == null ? Build.Flavor.UNKNOWN : Build.Flavor.fromDisplayName(buildFlavor, false),
+                            buildType == null ? Build.Type.UNKNOWN : Build.Type.fromDisplayName(buildType, false),
                             (String) value.get("build_hash"),
                             (String) value.get("build_date"),
                             (boolean) value.get("build_snapshot"),

server/src/test/java/org/elasticsearch/BuildTests.java

@@ -35,7 +35,10 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasToString;
+import static org.hamcrest.Matchers.sameInstance;
 
 public class BuildTests extends ESTestCase {
 
@@ -223,4 +226,43 @@ public void testSerializationBWC() throws IOException {
         assertThat(post67pre70.build.getQualifiedVersion(), equalTo(post67Pre70Version.toString()));
         assertThat(post70.build.getQualifiedVersion(), equalTo(dockerBuild.build.getQualifiedVersion()));
     }
+
+    public void testFlavorParsing() {
+        for (final Build.Flavor flavor : Build.Flavor.values()) {
+            // strict or not should not impact parsing at all here
+            assertThat(Build.Flavor.fromDisplayName(flavor.displayName(), randomBoolean()), sameInstance(flavor));
+        }
+    }
+
+    public void testTypeParsing() {
+        for (final Build.Type type : Build.Type.values()) {
+            // strict or not should not impact parsing at all here
+            assertThat(Build.Type.fromDisplayName(type.displayName(), randomBoolean()), sameInstance(type));
+        }
+    }
+
+    public void testLenientFlavorParsing() {
+        final String displayName = randomAlphaOfLength(8);
+        assertThat(Build.Flavor.fromDisplayName(displayName, false), equalTo(Build.Flavor.UNKNOWN));
+    }
+
+    public void testStrictFlavorParsing() {
+        final String displayName = randomAlphaOfLength(8);
+        @SuppressWarnings("ResultOfMethodCallIgnored") final IllegalStateException e =
+                expectThrows(IllegalStateException.class, () -> Build.Flavor.fromDisplayName(displayName, true));
+        assertThat(e, hasToString(containsString("unexpected distribution flavor [" + displayName + "]; your distribution is broken")));
+    }
+
+    public void testLenientTypeParsing() {
+        final String displayName = randomAlphaOfLength(8);
+        assertThat(Build.Type.fromDisplayName(displayName, false), equalTo(Build.Type.UNKNOWN));
+    }
+
+    public void testStrictTypeParsing() {
+        final String displayName = randomAlphaOfLength(8);
+        @SuppressWarnings("ResultOfMethodCallIgnored") final IllegalStateException e =
+                expectThrows(IllegalStateException.class, () -> Build.Type.fromDisplayName(displayName, true));
+        assertThat(e, hasToString(containsString("unexpected distribution type [" + displayName + "]; your distribution is broken")));
+    }
+
 }