Fix validator can specify gas limit

CHANGELOG.md

@@ -121,6 +121,7 @@ The format is based on Keep a Changelog, and this project adheres to Semantic Ve
 - Fix segmentation fault in E2E when light-client feature flag is enabled. [PR](https://github.com/prysmaticlabs/prysm/pull/14699)
 - Fix `searchForPeers` infinite loop in small networks.
 - Fix slashing pool behavior to enforce MaxAttesterSlashings limit in Electra version.
+- Fix validator gas limit usage through flag and file.
 
 ### Security
 

config/proposer/loader/BUILD.bazel

@@ -13,6 +13,7 @@ go_test(
         "//config/proposer:go_default_library",
         "//consensus-types/validator:go_default_library",
         "//encoding/bytesutil:go_default_library",
+        "//proto/prysm/v1alpha1/validator-client:go_default_library",
         "//testing/assert:go_default_library",
         "//testing/require:go_default_library",
         "//validator/db/iface:go_default_library",

config/proposer/loader/loader.go

@@ -265,6 +265,9 @@ func (psl *settingsLoader) processProposerSettings(loadedSettings, dbSettings *v
 	// process any overrides for proposer config
 	for _, option := range newSettings.ProposerConfig {
 		if option != nil {
+			if loadedSettings != nil && option.Builder != nil {
+				gasLimitOnly = &option.Builder.GasLimit
+			}
 			option.Builder = processBuilderConfig(option.Builder, builderConfig, gasLimitOnly)
 		}
 	}

config/proposer/loader/loader_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/prysmaticlabs/prysm/v5/config/proposer"
 	"github.com/prysmaticlabs/prysm/v5/consensus-types/validator"
 	"github.com/prysmaticlabs/prysm/v5/encoding/bytesutil"
+	validatorpb "github.com/prysmaticlabs/prysm/v5/proto/prysm/v1alpha1/validator-client"
 	"github.com/prysmaticlabs/prysm/v5/testing/assert"
 	"github.com/prysmaticlabs/prysm/v5/testing/require"
 	"github.com/prysmaticlabs/prysm/v5/validator/db/iface"
@@ -499,7 +500,7 @@ func TestProposerSettingsLoader(t *testing.T) {
 							},
 							BuilderConfig: &proposer.BuilderConfig{
 								Enabled:  true,
-								GasLimit: 50000000,
+								GasLimit: 40000000,
 							},
 						},
 					},
@@ -1003,3 +1004,27 @@ func Test_ProposerSettingsLoaderWithOnlyBuilder_DoesNotSaveInDB(t *testing.T) {
 		})
 	}
 }
+
+func Test_settingsLoader_processProposerSettings(t *testing.T) {
+	limit := validator.Uint64(30_000_000)
+	psl := &settingsLoader{
+		options: &flagOptions{
+			gasLimit: &limit,
+		},
+	}
+	loaded := &validatorpb.ProposerSettingsPayload{
+		ProposerConfig: map[string]*validatorpb.ProposerOptionPayload{
+			"bob": {
+				Builder: &validatorpb.BuilderConfig{
+					GasLimit: 40_000_000,
+				},
+			},
+		},
+	}
+	var db *validatorpb.ProposerSettingsPayload
+	got := psl.processProposerSettings(loaded, db)
+	require.NotNil(t, got)
+	for _, payload := range got.ProposerConfig {
+		require.Equal(t, validator.Uint64(40_000_000), payload.Builder.GasLimit)
+	}
+}