fix: Prevent overriding config with default flag values (#2642)

Closes: evstack/ev-abci#245

The ignite app should be bumped and ev-abci jobs should be bumped after
this.

Author: julienrbrt

pkg/config/config.go

@@ -402,6 +402,11 @@ func LoadFromViper(inputViper *viper.Viper) (Config, error) {
 
 	// then override with settings from input viper (higher precedence)
 	for _, key := range inputViper.AllKeys() {
+		// we must not override config with default flags value
+		if !inputViper.IsSet(key) {
+			continue
+		}
+
 		// Handle special case for prefixed keys
 		if after, ok := strings.CutPrefix(key, FlagPrefixEvnode); ok {
 			// Strip the prefix for the merged viper

pkg/config/config_test.go

@@ -279,6 +279,44 @@ signer:
 	require.Equal(t, "http://yaml-da:26657", cfgFromViper.DA.Address, "DA.Address should match YAML")
 	require.Equal(t, "file", cfgFromViper.Signer.SignerType, "Signer.SignerType should match YAML")
 	require.Equal(t, "something/config", cfgFromViper.Signer.SignerPath, "Signer.SignerPath should match YAML")
+
+	// Test that default flag values don't override config values when not explicitly set
+	t.Run("default flag values don't override config when not explicitly set", func(t *testing.T) {
+		// Create a viper instance that simulates having default values but IsSet() returns false
+		flagViper := viper.New()
+		flagViper.Set(FlagRootDir, tempDir)
+
+		// Create a command and parse empty args to simulate flags with defaults but not explicitly set
+		cmd = &cobra.Command{Use: "test"}
+		AddFlags(cmd)
+		AddGlobalFlags(cmd, "test")
+
+		// Bind the flags to viper - this populates viper with default values
+		// but since no args were provided, IsSet() will return false for these flags
+		err = flagViper.BindPFlags(cmd.Flags())
+		require.NoError(t, err)
+		err = flagViper.BindPFlags(cmd.PersistentFlags())
+		require.NoError(t, err)
+
+		// Parse empty command line - this means all flags have default values but IsSet() = false
+		err = cmd.ParseFlags([]string{})
+		require.NoError(t, err)
+
+		// Sanity check.
+		// Verify that IsSet returns false for flag values (this is the key behavior we're testing)
+		require.False(t, flagViper.IsSet("rollkit.node.aggregator"), "Flag should not be considered 'set' when using default")
+		require.False(t, flagViper.IsSet("rollkit.node.block_time"), "Flag should not be considered 'set' when using default")
+		require.False(t, flagViper.IsSet("rollkit.da.address"), "Flag should not be considered 'set' when using default")
+
+		cfgFromViper, err = LoadFromViper(flagViper)
+		require.NoError(t, err)
+
+		// These values should come from YAML, not be overridden by flag defaults
+		require.True(t, cfgFromViper.Node.Aggregator, "Node.Aggregator should remain true from YAML, not overridden by flag default")
+		require.Equal(t, "5s", cfgFromViper.Node.BlockTime.String(), "Node.BlockTime should remain 5s from YAML, not overridden by flag default")
+		require.Equal(t, "http://yaml-da:26657", cfgFromViper.DA.Address, "DA.Address should remain from YAML, not overridden by flag default")
+		require.Equal(t, "something/config", cfgFromViper.Signer.SignerPath, "Signer.SignerPath should remain from YAML, not overridden by flag default")
+	})
 }
 
 func TestDAConfig_GetDataNamespace(t *testing.T) {