clap-utils: Forbid multiple values for --signer

CHANGELOG.md

@@ -28,6 +28,7 @@ Release channels have their own copy of this changelog:
   * RPC's `simulateTransaction` now returns `innerInstructions` as `json`/`jsonParsed` (#34313).
   * Bigtable upload now includes entry summary data for each slot, stored in a
     new `entries` table
+  * Forbid multiple values for the `--signer` CLI flag, forcing users to specify multiple occurrences of `--signer`, one for each signature
 * Upgrade Notes
   * `solana-program` and `solana-sdk` default to support for Borsh v1, with
 limited backward compatibility for v0.10 and v0.9. Please upgrade to Borsh v1.

clap-utils/src/offline.rs

@@ -52,6 +52,7 @@ fn signer_arg<'a, 'b>() -> Arg<'a, 'b> {
         .validator(is_pubkey_sig)
         .requires(BLOCKHASH_ARG.name)
         .multiple(true)
+        .number_of_values(1)
         .help(SIGNER_ARG.help)
 }
 

clap-v3-utils/src/offline.rs

@@ -53,7 +53,7 @@ fn signer_arg<'a>() -> Arg<'a> {
         .value_parser(value_parser!(PubkeySignature))
         .requires(BLOCKHASH_ARG.name)
         .multiple_occurrences(true)
-        .multiple_values(true)
+        .multiple_values(false)
         .help(SIGNER_ARG.help)
 }