Disable blob pruning when set

Author: michaelsproul

beacon_node/src/config.rs

@@ -827,6 +827,12 @@ pub fn get_config<E: EthSpec>(
 
     client_config.chain.complete_blob_backfill = cli_args.get_flag("complete-blob-backfill");
 
+    // Ensure `prune_blobs` is false whenever complete-blob-backfill is set. This overrides any
+    // setting of `--prune-blobs true` applied earlier in flag parsing.
+    if client_config.chain.complete_blob_backfill {
+        client_config.store.prune_blobs = false;
+    }
+
     // Backfill sync rate-limiting
     client_config.beacon_processor.enable_backfill_rate_limiting =
         !cli_args.get_flag("disable-backfill-rate-limiting");

lighthouse/tests/beacon_node.rs

@@ -402,7 +402,23 @@ fn complete_blob_backfill_flag() {
     CommandLineTest::new()
         .flag("complete-blob-backfill", None)
         .run_with_zero_port()
-        .with_config(|config| assert!(config.chain.complete_blob_backfill));
+        .with_config(|config| {
+            assert!(config.chain.complete_blob_backfill);
+            assert!(!config.store.prune_blobs);
+        });
+}
+
+// Even if `--prune-blobs true` is provided, `--complete-blob-backfill` should override it to false.
+#[test]
+fn complete_blob_backfill_and_prune_blobs_true() {
+    CommandLineTest::new()
+        .flag("complete-blob-backfill", None)
+        .flag("prune-blobs", Some("true"))
+        .run_with_zero_port()
+        .with_config(|config| {
+            assert!(config.chain.complete_blob_backfill);
+            assert!(!config.store.prune_blobs);
+        });
 }
 
 // Tests for Eth1 flags.