Add CONFIG_NAME back into specs returned from REST API (Consensys#4054)

ethereum/spec/src/main/java/tech/pegasys/teku/spec/config/SpecConfigReader.java

@@ -45,9 +45,11 @@
 public class SpecConfigReader {
   private static final Logger LOG = LogManager.getLogger();
   private static final String PRESET_KEY = "PRESET_BASE";
+  private static final String CONFIG_NAME_KEY = "CONFIG_NAME";
   private static final ImmutableSet<String> KEYS_TO_IGNORE =
       ImmutableSet.of(
           PRESET_KEY,
+          CONFIG_NAME_KEY,
           // Unsupported, upcoming fork-related keys
           "MERGE_FORK_VERSION",
           "MERGE_FORK_EPOCH",
@@ -125,11 +127,18 @@ private String castPresetValue(final Object preset) {
   public void loadFromMap(final Map<String, ?> rawValues) {
     processSeenValues(rawValues);
     final Map<String, Object> unprocessedConfig = new HashMap<>(rawValues);
+    final Map<String, Object> apiSpecConfig = new HashMap<>(rawValues);
     // Remove any keys that we're ignoring
-    KEYS_TO_IGNORE.forEach(unprocessedConfig::remove);
+    KEYS_TO_IGNORE.forEach(
+        key -> {
+          unprocessedConfig.remove(key);
+          if (!key.equals(PRESET_KEY) && !key.equals(CONFIG_NAME_KEY)) {
+            apiSpecConfig.remove(key);
+          }
+        });
 
     // Process phase0 config
-    configBuilder.rawConfig(unprocessedConfig);
+    configBuilder.rawConfig(apiSpecConfig);
     streamConfigSetters(configBuilder.getClass())
         .forEach(
             setter -> {

ethereum/spec/src/test/java/tech/pegasys/teku/spec/config/SpecConfigLoaderTest.java

@@ -32,6 +32,7 @@
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
+import org.junit.jupiter.params.provider.ValueSource;
 import tech.pegasys.teku.spec.networks.Eth2Network;
 import tech.pegasys.teku.util.config.Constants;
 
@@ -45,6 +46,21 @@ public void shouldLoadAllKnownNetworks(final String name, final Class<?> configT
     assertAllFieldsSet(config, configType);
   }
 
+  /**
+   * For the three networks supported by Infura, go the extra mile and ensure the CONFIG_NAME key is
+   * still included in the raw config which is exposed by the config/spec REST API.
+   *
+   * <p>Prior to Altair, Lighthouse required this field to be a known testnet name, mainnet or
+   * minimal. Post-Altair we will be able to remove this as the new PRESET_BASE key will be
+   * sufficient.
+   */
+  @ParameterizedTest(name = "{0}")
+  @ValueSource(strings = {"prater", "pyrmont", "mainnet"})
+  public void shouldMaintainConfigNameBackwardsCompatibility(final String name) {
+    final SpecConfig config = SpecConfigLoader.loadConfig(name);
+    assertThat(config.getRawConfig().get("CONFIG_NAME")).isEqualTo(name);
+  }
+
   @Test
   public void shouldLoadMainnet() throws Exception {
     final SpecConfig config = SpecConfigLoader.loadConfig("mainnet");

util/src/main/java/tech/pegasys/teku/util/config/ConstantsReader.java

@@ -41,6 +41,7 @@ class ConstantsReader {
   private static final ImmutableList<String> FIELDS_TO_IGNORE =
       ImmutableList.of(
           PRESET_FIELD,
+          "CONFIG_NAME", // Legacy field
           // Altair fields
           "ALTAIR_FORK_VERSION",
           "ALTAIR_FORK_EPOCH",

util/src/main/resources/tech/pegasys/teku/util/config/configs/mainnet.yaml

@@ -3,6 +3,9 @@
 # Extends the mainnet preset
 PRESET_BASE: 'mainnet'
 
+# For backwards compatibility in the config/spec API
+CONFIG_NAME: "mainnet"
+
 # Genesis
 # ---------------------------------------------------------------
 # `2**14` (= 16,384)

util/src/main/resources/tech/pegasys/teku/util/config/configs/prater.yaml

@@ -1,5 +1,8 @@
 # Prater preset
 
+# For backwards compatibility in the config/spec API
+CONFIG_NAME: "prater"
+
 # Misc
 # ---------------------------------------------------------------
 # 2**6 (= 64)

util/src/main/resources/tech/pegasys/teku/util/config/configs/pyrmont.yaml

@@ -1,5 +1,8 @@
 # Pyrmont preset
 
+# For backwards compatibility in the config/spec API
+CONFIG_NAME: "pyrmont"
+
 # Misc
 # ---------------------------------------------------------------
 # 2**6 (= 64)