dynamically generate string of network names

bitcoin/chainparams.c

@@ -123,3 +123,11 @@ const struct chainparams *chainparams_by_bip173(const char *bip173_name)
 	}
 	return NULL;
 }
+
+const char *chainparams_get_network_names(const tal_t *ctx)
+{
+    char *networks_string = tal_strdup(ctx, networks[0].network_name);
+    for (size_t i = 1; i < ARRAY_SIZE(networks); ++i)
+        tal_append_fmt(&networks_string, ", %s", networks[i].network_name);
+    return networks_string;
+}

bitcoin/chainparams.h

@@ -4,6 +4,7 @@
 #include "config.h"
 #include <bitcoin/block.h>
 #include <ccan/short_types/short_types.h>
+#include <ccan/tal/str/str.h>
 #include <common/amount.h>
 #include <stdbool.h>
 
@@ -53,4 +54,9 @@ const struct chainparams *chainparams_by_bip173(const char *bip173_name);
  */
 const struct chainparams *chainparams_by_chainhash(const struct bitcoin_blkid *chain_hash);
 
+/**
+ * chainparams_get_network_names - Produce a comma-separated list of network names
+ */
+const char *chainparams_get_network_names(const tal_t *ctx);
+
 #endif /* LIGHTNING_BITCOIN_CHAINPARAMS_H */

wallet/wallet.c

@@ -2239,12 +2239,12 @@ bool wallet_network_check(struct wallet *w,
 					   "match network blockchain hash: %s "
 					   "!= %s. "
 					   "Are you on the right network? "
-					   "(--network={bitcoin, testnet, regtest, "
-					   "litecoin or litecoin-testnet})",
+					   "(--network={one of %s})",
 				   type_to_string(w, struct bitcoin_blkid,
 						  &chainhash),
 				   type_to_string(w, struct bitcoin_blkid,
-						  &chainparams->genesis_blockhash));
+						  &chainparams->genesis_blockhash),
+				   chainparams_get_network_names(tmpctx));
 			return false;
 		}
 	} else {