make sure request_uid is actually unique

Allowing duplicate request_uid for different transfer details means that
somebody might eventually rely on this, which is bad.  They should
really be unique, it makes tracing easier.

2 files changed, 12 insertions, 3 deletions

diff --git a/src/include/taler_error_codes.h b/src/include/taler_error_codes.h
index 3833e7a4e..ac7f92888 100644
--- a/src/include/taler_error_codes.h
+++ b/src/include/taler_error_codes.h
@@ -1736,6 +1736,12 @@ enum TALER_ErrorCode
   TALER_EC_BANK_SOFT_EXCEPTION = 5400,
 
   /**
+   * The request UID for a request to transfer funds has already been
+   * used, but with different details for the transfer.
+   */
+  TALER_EC_BANK_TRANSFER_REQUEST_UID_REUSED = 5500,
+
+  /**
    * The sync service failed to access its database. This response is
    * provided with HTTP status code MHD_HTTP_INTERNAL_SERVER_ERROR.
    */
diff --git a/src/include/taler_fakebank_lib.h b/src/include/taler_fakebank_lib.h
index 278d0a00d..9324bdce1 100644
--- a/src/include/taler_fakebank_lib.h
+++ b/src/include/taler_fakebank_lib.h
@@ -73,9 +73,11 @@ TALER_FAKEBANK_check_empty (struct TALER_FAKEBANK_Handle *h);
  * @param subject wire transfer subject to use
  * @param exchange_base_url exchange URL
  * @param request_uid unique number to make the request unique, or NULL to create one
- * @return serial_id of the transfer
+ * @param[out] ret_row_id pointer to store the row ID of this transaction
+ * @return GNUNET_YES if the transfer was successful,
+ *         GNUNET_SYSERR if the request_uid was reused for a different transfer
  */
-uint64_t
+int
 TALER_FAKEBANK_make_transfer (struct TALER_FAKEBANK_Handle *h,
                               const char *debit_account,
                               const char *credit_account,
@@ -83,7 +85,8 @@ TALER_FAKEBANK_make_transfer (struct TALER_FAKEBANK_Handle *h,
                               const struct
                               TALER_WireTransferIdentifierRawP *subject,
                               const char *exchange_base_url,
-                              const struct GNUNET_HashCode *request_uid);
+                              const struct GNUNET_HashCode *request_uid,
+                              uint64_t *ret_row_id);
 
 
 /**