restored consistency in refCount accounting by array traces [Bug #4484339]

3 files changed, 24 insertions, 4 deletions

diff --git a/ChangeLog b/ChangeLog
index 737ecd4..2ae86b4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2001-12-07  Miguel Sofer  <msofer@users.sourceforge.net>
+
+	* generic/tclVar.c: 
+	* tests/trace.test: restored consistency in refCount accounting by
+	array traces [Bug #4484339], submitted by Don Porter. 
+
 2001-12-06  Donal K. Fellows  <fellowsd@cs.man.ac.uk>
 
 	* tests/parseExpr.test, tests/for.test, tests/expr.test:
diff --git a/generic/tclVar.c b/generic/tclVar.c
index 401e36b..134ca16 100644
--- a/generic/tclVar.c
+++ b/generic/tclVar.c
@@ -15,7 +15,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclVar.c,v 1.43 2001/12/05 20:43:58 msofer Exp $
+ * RCS: @(#) $Id: tclVar.c,v 1.44 2001/12/07 13:55:59 msofer Exp $
  */
 
 #include "tclInt.h"
@@ -4514,6 +4514,9 @@ CallTraces(iPtr, arrayPtr, varPtr, part1, part2, flags, resultTypePtr)
     }
     varPtr->flags |= VAR_TRACE_ACTIVE;
     varPtr->refCount++;
+    if (arrayPtr != NULL) {
+	arrayPtr->refCount++;
+    }
 
     /*
      * If the variable name hasn't been parsed into array name and
@@ -4556,7 +4559,6 @@ CallTraces(iPtr, arrayPtr, varPtr, part1, part2, flags, resultTypePtr)
     iPtr->activeTracePtr = &active;
     Tcl_Preserve((ClientData) iPtr);
     if (arrayPtr != NULL && !(arrayPtr->flags & VAR_TRACE_ACTIVE)) {
-	arrayPtr->refCount++;
 	active.varPtr = arrayPtr;
 	for (tracePtr = arrayPtr->tracePtr;  tracePtr != NULL;
 	     tracePtr = active.nextTracePtr) {
diff --git a/tests/trace.test b/tests/trace.test
index beab9c6..6a5cc88 100644
--- a/tests/trace.test
+++ b/tests/trace.test
@@ -11,7 +11,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: trace.test,v 1.15 2001/12/05 20:43:58 msofer Exp $
+# RCS: @(#) $Id: trace.test,v 1.16 2001/12/07 13:55:59 msofer Exp $
 
 if {[lsearch [namespace children] ::tcltest] == -1} {
     package require tcltest
@@ -56,6 +56,18 @@ proc traceCommand {oldName newName op} {
     global info
     set info [list $oldName $newName $op]
 }
+
+test trace-0.0 {memory corruption in trace (Tcl Bug 484339)} {
+    # You may need Purify or Electric Fence to reliably
+    # see this one fail.
+    catch {unset z}
+    trace add variable z array {set z(foo) 1 ;#}
+    set res "names: [array names z]"
+    catch {unset ::z}
+    trace variable ::z w {unset ::z; error "memory corruption";#}
+    list [catch {set ::z 1} msg] $msg
+} {1 {can't set "::z": memory corruption}}
+
 # Read-tracing on variables
 
 test trace-1.1 {trace variable reads} {
@@ -913,7 +925,7 @@ test trace-15.3 {special list-handling in trace commands} {
     trace add variable "x y z(a\n\{)" write traceProc
     set "x y z(a\n\{)" 33
     set info
-} "{x y z} a\\n\\{ write"
+} "{x y z} a\\n\\\{ write"
 
 # Check for proper handling of unsets during traces.