* generic/tclBasic.c: Made the walk of the active trace list aware

        * generic/tclCmdMZ.c:   of the direction of trace scanning, so the
        * generic/tclInt.h:     proper correction can be made. [Bug 1224585]
        * tests/trace.test (trace-34.2,3):

6 files changed, 56 insertions, 10 deletions

diff --git a/ChangeLog b/ChangeLog
index f31078e..f4e887b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,11 @@
 
 	*** 8.4.11 TAGGED FOR RELEASE ***
 
+	* generic/tclBasic.c:	Made the walk of the active trace list aware
+	* generic/tclCmdMZ.c:	of the direction of trace scanning, so the
+	* generic/tclInt.h:	proper correction can be made. [Bug 1224585]
+	* tests/trace.test (trace-34.2,3):
+
 	* generic/tclBasic.c (Tcl_DeleteTrace):	Added missing walk of the
 	* tests/trace.test (trace-34.1):	list of active traces to
 	cleanup references to traces being deleted. [Bug 1201035]
diff --git a/changes b/changes
index 1e6bf4d..cf603c4 100644
--- a/changes
+++ b/changes
@@ -1,6 +1,6 @@
 Recent user-visible changes to Tcl:
 
-RCS: @(#) $Id: changes,v 1.79.2.19 2005/06/18 19:52:36 dgp Exp $
+RCS: @(#) $Id: changes,v 1.79.2.20 2005/06/21 17:19:40 dgp Exp $
 
 1. No more [command1] [command2] construct for grouping multiple
 commands on a single command line.
@@ -6213,4 +6213,6 @@ Documentation improvements [1075433,1085127,1117017,1124160,1149605,etc.]
 
 2005-06-18 (bug fix)[1154163] [format %h] on 64-bit OS's (kraft,fellows)
 
+2005-06-21 (bug fix)[1201035,1224585] execution trace crashes (porter)
+
 --- Released 8.4.11, June 24, 2005 --- See ChangeLog for details ---
diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index ccb6de9..f1423cf 100644
--- a/generic/tclBasic.c
+++ b/generic/tclBasic.c
@@ -13,7 +13,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclBasic.c,v 1.75.2.15 2005/06/21 14:44:58 dgp Exp $
+ * RCS: @(#) $Id: tclBasic.c,v 1.75.2.16 2005/06/21 17:19:40 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -2585,6 +2585,7 @@ CallCommandTraces(iPtr, cmdPtr, oldName, newName, flags)
     
     result = NULL;
     active.nextPtr = iPtr->activeCmdTracePtr;
+    active.reverseScan = 0;
     iPtr->activeCmdTracePtr = &active;
 
     if (flags & TCL_TRACE_DELETE) {
@@ -5158,7 +5159,7 @@ Tcl_DeleteTrace(interp, trace)
 				 * Tcl_CreateTrace). */
 {
     Interp *iPtr = (Interp *) interp;
-    Trace *tracePtr = (Trace *) trace;
+    Trace *prevPtr, *tracePtr = (Trace *) trace;
     register Trace **tracePtr2 = &(iPtr->tracePtr);
     ActiveInterpTrace *activePtr;
 
@@ -5167,7 +5168,9 @@ Tcl_DeleteTrace(interp, trace)
      * and remove it from the list.
      */
 
+    prevPtr = NULL;
     while ((*tracePtr2) != NULL && (*tracePtr2) != tracePtr) {
+	prevPtr = *tracePtr2;
 	tracePtr2 = &((*tracePtr2)->nextPtr);
     }
     if (*tracePtr2 == NULL) {
@@ -5184,7 +5187,11 @@ Tcl_DeleteTrace(interp, trace)
     for (activePtr = iPtr->activeInterpTracePtr;  activePtr != NULL;
 	    activePtr = activePtr->nextPtr) {
 	if (activePtr->nextTracePtr == tracePtr) {
-	    activePtr->nextTracePtr = tracePtr->nextPtr;
+	    if (activePtr->reverseScan) {
+		activePtr->nextTracePtr = prevPtr;
+	    } else {
+		activePtr->nextTracePtr = tracePtr->nextPtr;
+	    }
 	}
     }
 
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index 0c9ff94..1ab108f 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -14,7 +14,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCmdMZ.c,v 1.82.2.19 2005/05/25 19:25:57 hobbs Exp $
+ * RCS: @(#) $Id: tclCmdMZ.c,v 1.82.2.20 2005/06/21 17:19:42 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -3972,7 +3972,11 @@ Tcl_UntraceCommand(interp, cmdName, flags, proc, clientData)
     for (activePtr = iPtr->activeCmdTracePtr;  activePtr != NULL;
 	 activePtr = activePtr->nextPtr) {
 	if (activePtr->nextTracePtr == tracePtr) {
-	    activePtr->nextTracePtr = tracePtr->nextPtr;
+	    if (activePtr->reverseScan) {
+		activePtr->nextTracePtr = prevPtr;
+	    } else {
+		activePtr->nextTracePtr = tracePtr->nextPtr;
+	    }
 	}
     }
     if (prevPtr == NULL) {
@@ -4201,6 +4205,7 @@ TclCheckExecutionTraces(interp, command, numChars, cmdPtr, code,
 	 tracePtr = active.nextTracePtr) {
         if (traceFlags & TCL_TRACE_LEAVE_EXEC) {
             /* execute the trace command in order of creation for "leave" */
+	    active.reverseScan = 1;
 	    active.nextTracePtr = NULL;
             tracePtr = cmdPtr->tracePtr;
             while (tracePtr->nextPtr != lastTracePtr) {
@@ -4208,6 +4213,7 @@ TclCheckExecutionTraces(interp, command, numChars, cmdPtr, code,
 	        tracePtr = tracePtr->nextPtr;
             }
         } else {
+	    active.reverseScan = 0;
 	    active.nextTracePtr = tracePtr->nextPtr;
         }
 	tcmdPtr = (TraceCommandInfo*)tracePtr->clientData;
@@ -4225,7 +4231,9 @@ TclCheckExecutionTraces(interp, command, numChars, cmdPtr, code,
 	        ckfree((char*)tcmdPtr);
 	    }
 	}
-        lastTracePtr = tracePtr;
+	if (active.nextTracePtr) {
+	    lastTracePtr = active.nextTracePtr->nextPtr;
+	}
     }
     iPtr->activeCmdTracePtr = active.nextPtr;
     return(traceCode);
@@ -4296,6 +4304,7 @@ TclCheckInterpTraces(interp, command, numChars, cmdPtr, code,
              * Tcl_CreateObjTrace creates one more linked list of traces
              * which results in one more reversal of trace invocation.
              */
+	    active.reverseScan = 1;
 	    active.nextTracePtr = NULL;
             tracePtr = iPtr->tracePtr;
             while (tracePtr->nextPtr != lastTracePtr) {
@@ -4303,6 +4312,7 @@ TclCheckInterpTraces(interp, command, numChars, cmdPtr, code,
 	        tracePtr = tracePtr->nextPtr;
             }
         } else {
+	    active.reverseScan = 0;
 	    active.nextTracePtr = tracePtr->nextPtr;
         }
 	if (tracePtr->level > 0 && curLevel > tracePtr->level) {
@@ -4347,7 +4357,9 @@ TclCheckInterpTraces(interp, command, numChars, cmdPtr, code,
 	    tracePtr->flags &= ~TCL_TRACE_EXEC_IN_PROGRESS;
 	    Tcl_Release((ClientData) tracePtr);
 	}
-        lastTracePtr = tracePtr;
+	if (active.nextTracePtr) {
+	    lastTracePtr = active.nextTracePtr->nextPtr;
+	}
     }
     iPtr->activeInterpTracePtr = active.nextPtr;
     return(traceCode);
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 2716467..45eb8ff 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclInt.h,v 1.118.2.11 2005/06/18 21:46:42 das Exp $
+ * RCS: @(#) $Id: tclInt.h,v 1.118.2.12 2005/06/21 17:19:43 dgp Exp $
  */
 
 #ifndef _TCLINT
@@ -336,6 +336,8 @@ typedef struct ActiveCommandTrace {
 				 * trace procedure returns;  if this
 				 * trace gets deleted, must update pointer
 				 * to avoid using free'd memory. */
+    int reverseScan;		/* Boolean set true when the traces
+				 * are scanning in reverse order. */
 } ActiveCommandTrace;
 
 /*
@@ -709,6 +711,8 @@ typedef struct ActiveInterpTrace {
 				 * trace procedure returns;  if this
 				 * trace gets deleted, must update pointer
 				 * to avoid using free'd memory. */
+    int reverseScan;		/* Boolean set true when the traces
+				 * are scanning in reverse order. */
 } ActiveInterpTrace;
 
 /*
diff --git a/tests/trace.test b/tests/trace.test
index 4456afa..e0c6648 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 1.26.2.5 2005/06/21 14:44:59 dgp Exp $
+# RCS: @(#) $Id: trace.test,v 1.26.2.6 2005/06/21 17:19:43 dgp Exp $
 
 if {[lsearch [namespace children] ::tcltest] == -1} {
     package require tcltest
@@ -2156,6 +2156,22 @@ test trace-34.1 {Bug 1201035} {
     set ::x
 } {{{lappend ::x foo} enterstep} done foo}
 
+test trace-34.2 {Bug 1224585} {
+    proc foo {} {}
+    proc bar args {trace remove execution foo leave soom}
+    trace add execution foo leave bar
+    trace add execution foo leave soom
+    foo
+} {}
+
+test trace-34.3 {Bug 1224585} {
+    proc foo {} {set x {}}
+    proc bar args {trace remove execution foo enterstep soom}
+    trace add execution foo enterstep soom
+    trace add execution foo enterstep bar
+    foo
+} {}
+
 # Delete procedures when done, so we don't clash with other tests
 # (e.g. foobar will clash with 'unknown' tests).
 catch {rename foobar {}}