Fix GitLab issue #69: repeated knive caveat message

NEWS.adoc

@@ -2,6 +2,9 @@
 // SPDX-FileCopyrightText: (C) Eric S. Raymond <esr@thyrsus.com>
 // SPDX-License-Identifier: CC-BY-4.0
 
+Repository head::
+  Ensore that the KNIVES_VANISH message can't issue twice.
+
 1.18: 2024-02-15::
   Bring the manual page fully up to date.
 

main.c

@@ -1280,11 +1280,13 @@ static bool do_command(void) {
 				}
 			}
 
-			/* Check to see if the room is dark. If the knife is
-			 * here, and it's dark, the knife permanently disappears
-			 */
+			/* Check to see if the room is dark. */
 			game.wzdark = DARK(game.loc);
-			if (game.knfloc != LOC_NOWHERE &&
+		     
+			/* If the knife is not here it permanently disappears.
+			* Possibly this should fire if the knife is here but
+			* the room is dark? */
+			if (game.knfloc > LOC_NOWHERE &&
 			    game.knfloc != game.loc) {
 				game.knfloc = LOC_NOWHERE;
 			}

notes.adoc

@@ -78,7 +78,11 @@ Bug fixes:
   "eying" for "eyeing", "thresholds" for "threshholds".
 
 * Under odd circumstances (dropping rug or vase outdoors) the game could
-  formerly say "floor" when it should say "ground" (or "dirt", or something).
+  formerly say "floor" when it should say "ground" (or "dirt", or
+  something).
+
+* The "knives vanish" message could formerly be emitted when "I see no
+  knife here." would be appropriate.
 
 Enhancements:
 

tests/knife.chk

@@ -369,7 +369,7 @@ A crystal bridge spans the fissure.
 
 > get knife
 
-The dwarves' knives vanish as they strike the walls of the cave.
+I see no knife here.
 
 > quit