test contract inputs

controller/src/command.rs

@@ -2065,19 +2065,48 @@ mod contract_tests {
 	}
 
 	#[test]
-	fn contract_sign_fee_rate() {
+	fn contract_sign_args() {
 		let args = ContractSetupArgs {
 			counterparty_addr: None,
 			receive: None,
 			send: None,
 			as_json: false,
-			use_inputs: None,
+			use_inputs: Some("commitment".to_string()),
 			make_outputs: None,
 			minimum_confirmations: None,
 			fee_rate: Some(2),
 			outfile: None,
 			add_outputs: false,
 		};
-		assert_eq!(args.to_api_args().unwrap().fee_rate, Some(2));
+		let api_args = args.to_api_args().unwrap();
+		assert_eq!(api_args.fee_rate, Some(2));
+		assert_eq!(
+			api_args.selection_args.use_inputs.as_deref(),
+			Some("commitment")
+		);
+	}
+
+	#[test]
+	fn contract_new_args() {
+		let args = ContractNewArgs {
+			counterparty_addr: None,
+			receive: Some(1),
+			send: None,
+			src_acct_name: None,
+			num_participants: 2,
+			as_json: false,
+			use_inputs: Some("commitment".to_string()),
+			make_outputs: None,
+			minimum_confirmations: 1,
+			ttl_blocks: None,
+			fee_rate: None,
+			outfile: None,
+			add_outputs: false,
+		};
+		let api_args = args.to_api_args().unwrap();
+		assert_eq!(
+			api_args.setup_args.selection_args.use_inputs.as_deref(),
+			Some("commitment")
+		);
 	}
 }

doc/contracts.md

@@ -29,7 +29,8 @@ to balance that side of the transaction.
 
 Payjoin is used by default. A receiver adds an input when one is available. An empty wallet
 can still receive; the fee is then taken from the received output. `--no-payjoin` prevents
-the receiver from adding an input and cannot be used together with `--use-inputs`.
+the receiver from adding an input and cannot be used together with `--use-inputs`. Pass one
+or more comma-separated output commitments to `--use-inputs` to select specific payjoin inputs.
 
 Inputs and outputs are normally picked when signing. `--add-outputs` picks and locks them
 during `new`. Prepared outputs appear as unconfirmed in the wallet, but are only added to

libwallet/src/contract/actions/README.md

@@ -39,8 +39,6 @@ Separating side effects until the 'save_step' part would make these functions mu
 
  - Reserve funds across open late-locked contracts, or make the possible signing failure
    clearer to callers.
- - For a payjoin, `--use-inputs any` picks an input for us; naming the commitment would be
-   clearer, for the API as much as the CLI.
  - Raise the replacement fee when `revoke` races a transaction already in the mempool.
  - Merge invoice-proof retrieval with the existing payment-proof API.
  - Add a Grin node API for kernel lookup by MMR index, then use the witness index instead

libwallet/src/contract/selection.rs

@@ -586,8 +586,8 @@ mod tests {
 	}
 
 	#[test]
-	fn receiver_payjoin_exact() {
+	fn receiver_payjoin_inputs() {
-		// net_change=-my_fees(1, 1), inputs=[my_fees(1, 0)], no fee committed => Ok([3, my_fees(2, 1)], fees)
+		// A receiver payjoin uses the smallest input unless one is named
 		let setup_args = ContractSetupArgsAPI {
 			// we expect to receive exactly our fee contribution my_fees(1, 1)
 			net_change: Some(my_fee_contribution(1, 1, 1, 2).unwrap().fee() as i64),
@@ -608,6 +608,11 @@ mod tests {
 			result_ref,
 			(expected_inputs, expected_output_amounts, expected_fee)
 		);
+
+		let mut named_args = setup_args.clone();
+		named_args.selection_args.use_inputs = Some("abc1".to_string());
+		let result = compute(&named_args, None, &mut inputs.clone()).unwrap();
+		assert_eq!(result.0, vec![inputs[1].clone()]);
 	}
 
 	#[test]

tests/cmd_line_contract.rs

@@ -374,6 +374,10 @@ fn parses_contract_options() {
 			"grin-wallet",
 			"contract",
 			"sign",
+			"--receive",
+			"1",
+			"--use-inputs",
+			"commitment",
 			"--min_conf",
 			"3",
 			"--fee_rate",
@@ -388,6 +392,7 @@ fn parses_contract_options() {
 	assert_eq!(parsed.minimum_confirmations, Some(3));
 	assert_eq!(parsed.fee_rate, Some(2));
 	assert_eq!(parsed.outfile.as_deref(), Some("sign.slatepack"));
+	assert_eq!(parsed.use_inputs.as_deref(), Some("commitment"));
 
 	let args = app
 		.get_matches_from_safe(vec![
@@ -421,6 +426,8 @@ fn selection_locks_early() {
 	};
 
 	assert!(!parse(&[]).add_outputs);
-	assert!(parse(&["--use-inputs", "commitment"]).add_outputs);
+	let selected = parse(&["--use-inputs", "commitment"]);
+	assert!(selected.add_outputs);
+	assert_eq!(selected.use_inputs.as_deref(), Some("commitment"));
 	assert!(parse(&["--make-outputs", "1"]).add_outputs);
 }