From: nethack.rankin <nethack.rankin>
Date: Sun, 20 Jan 2002 09:53:36 +0000 (+0000)
Subject: stale spellbook pointer
X-Git-Tag: MOVE2GIT~3415
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e2175c2ce16b8aa1ad393e15993df21da3349cd6;p=nethack

stale spellbook pointer

     If you get interrupted while reading a spellbook and then
the book gets destroyed or you change levels, the object pointer
remembered for the book will be invalid and could accidentally
match one subsequently allocated to some other book.  That would
result in "you continue your efforts to memorize the spell" when
starting to read that other book; it would also end up bypassing
the reading difficulty check and reuse the old book's delay counter.

     I don't remember who reported this.  It was quite some time
ago and I have an abandoned patch dated last March from when I
first started to fix it.

Files patched:
  include/extern.h
  src/save.c, shk.c, spell.c
---

diff --git a/doc/fixes33.2 b/doc/fixes33.2
index 9bea526d9..d6bf5da2a 100644
--- a/doc/fixes33.2
+++ b/doc/fixes33.2
@@ -493,6 +493,8 @@ add wizard #poly and #levelchange (originally levelgain; Dylan O'Donnell),
 add Jason Short's additional lenses use patch
 add new Gnomish Mines levels from Kelly Bailey's patch
 jousting by players wielding a lance while riding
+when reading spellbooks, don't "continue studying" wrong book if original one
+	gets destroyed after previous reading attempt has been interrupted
 
 
 Platform- and/or Interface-Specific New Features
diff --git a/include/extern.h b/include/extern.h
index 6a9ce1b30..f786e60db 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1808,6 +1808,7 @@ E boolean FDECL(load_special, (const char *));
 E int NDECL(learn);
 #endif
 E int FDECL(study_book, (struct obj *));
+E void FDECL(book_disappears, (struct obj *));
 E void FDECL(book_substitution, (struct obj *,struct obj *));
 E void NDECL(age_spells);
 E int NDECL(docast);
diff --git a/src/save.c b/src/save.c
index 1e6720add..f70fbfbdf 100644
--- a/src/save.c
+++ b/src/save.c
@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)save.c	3.3	2000/07/27	*/
+/*	SCCS Id: @(#)save.c	3.3	2002/01/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -840,7 +840,8 @@ register struct obj *otmp;
 	    if (Has_contents(otmp))
 		saveobjchn(fd,otmp->cobj,mode);
 	    if (release_data(mode)) {
-		if(otmp->oclass == FOOD_CLASS) food_disappears(otmp);
+		if (otmp->oclass == FOOD_CLASS) food_disappears(otmp);
+		if (otmp->oclass == SPBOOK_CLASS) book_disappears(otmp);
 		otmp->where = OBJ_FREE;	/* set to free so dealloc will work */
 		otmp->timed = 0;	/* not timed any more */
 		otmp->lamplit = 0;	/* caller handled lights */
diff --git a/src/shk.c b/src/shk.c
index ff64a11fb..3451e1942 100644
--- a/src/shk.c
+++ b/src/shk.c
@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)shk.c	3.3	2001/12/06	*/
+/*	SCCS Id: @(#)shk.c	3.3	2002/01/19	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -770,9 +770,9 @@ register struct obj *obj, *merge;
 	register struct bill_x *bpm;
 	register struct monst *shkp;
 
-
 	if (obj->otyp == LEASH && obj->leashmon) o_unleash(obj);
 	if (obj->oclass == FOOD_CLASS) food_disappears(obj);
+	if (obj->oclass == SPBOOK_CLASS) book_disappears(obj);
 	if (Has_contents(obj)) delete_contents(obj);
 
 	shkp = 0;
diff --git a/src/spell.c b/src/spell.c
index eecd15b48..0d3fec3b8 100644
--- a/src/spell.c
+++ b/src/spell.c
@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)spell.c	3.3	2001/12/03	*/
+/*	SCCS Id: @(#)spell.c	3.3	2002/01/19	*/
 /*	Copyright (c) M. Stephenson 1988			  */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -453,6 +453,15 @@ register struct obj *spellbook;
 	return(1);
 }
 
+/* a spellbook has been destroyed or the character has changed levels;
+   the stored address for the current book is no longer valid */
+void
+book_disappears(obj)
+struct obj *obj;
+{
+	if (obj == book) book = (struct obj *)0;
+}
+
 /* renaming an object usually results in it having a different address;
    so the sequence start reading, get interrupted, name the book, resume
    reading would read the "new" book from scratch */
@@ -1176,5 +1185,4 @@ struct obj *obj;
 	return;
 }
 
-
 /*spell.c*/