From: Markus Armbruster <armbru@pond.sub.org>
Date: Tue, 12 Jan 2021 20:42:42 +0000 (+0100)
Subject: buy: Don't continue when lot changes while asking for bid
X-Git-Tag: v4.4.1~22
X-Git-Url: http://git.pond.sub.org/?p=empserver;a=commitdiff_plain;h=1b677a4578ab5c5b8a40ff5101bee76ecef6f89e

buy: Don't continue when lot changes while asking for bid

When the lot being bid for changes while the player is at the "How
much" prompt, we report "Commodity #%d has changed!", and continue
with the changed lot.

If continuing is okay, we should keep quiet.  We did that until commit
40b11c098 "Fix buy not to wipe out concurrent updates", v4.3.27.  Okay
when only the lot's price changed.

However, the lot could have gone away, or even be reused for something
else.  Failing the command seems safest for the player, so do that.
It's how we use the check_FOO_ok() elsewhere.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
---

diff --git a/src/lib/commands/buy.c b/src/lib/commands/buy.c
index 3b24033e2..3d7b079bf 100644
--- a/src/lib/commands/buy.c
+++ b/src/lib/commands/buy.c
@@ -30,7 +30,7 @@
  *     Dave Pare, 1986
  *     Pat Loney, 1992
  *     Steve McClure, 1996-2000
- *     Markus Armbruster, 2004-2018
+ *     Markus Armbruster, 2004-2021
  */
 
 #include <config.h>
@@ -101,6 +101,8 @@ buy(void)
     bid = atof(p);
     if (bid <= 0)
 	return RET_FAIL;
+    if (!check_comm_ok(&comm))
+	return RET_FAIL;
     if (natp->nat_money < bid * comm.com_amount * buytax) {
 	pr("This purchase would cost %.2f, %.2f more than you have.\n",
 	   bid * comm.com_amount * buytax,
@@ -126,7 +128,6 @@ buy(void)
 	}
     }
     canspend = natp->nat_money - tally;
-    check_comm_ok(&comm);
     if (bid * comm.com_amount * buytax > canspend) {
 	pr("You have overextended yourself in the market\n");
 	pr("You can not bid on the current items at that price.\n");