* generic/tclBasic.c: Added missing walk of the list of active traces

        * generic/tclTrace.c:   to cleanup references to traces being deleted.
        * generic/tclInt.h:     [Bug 1201035] Made the walk of the active trace
        * tests/trace.test (trace-34.*): list aware of the direction of trace
        scanning, so the proper correction can be made. [Bug 1224585]

5 files changed, 87 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index df2c8a9..5b7b8da 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2005-06-21  Don Porter  <dgp@users.sourceforge.net>
+
+        * generic/tclBasic.c:   Added missing walk of the list of active traces
+        * generic/tclTrace.c:   to cleanup references to traces being deleted.
+        * generic/tclInt.h:     [Bug 1201035] Made the walk of the active trace
+        * tests/trace.test (trace-34.*): list aware of the direction of trace
+	scanning, so the proper correction can be made. [Bug 1224585]
+
 2005-06-21  Donal K. Fellows  <dkf@users.sf.net>
 
 	* unix/tcl.m4 (SC_ENABLE_SYMBOLS): Only enable the 'compile'
diff --git a/generic/tclBasic.c b/generic/tclBasic.c
index 42f5465..0d9cdec 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 1.161 2005/06/14 13:46:02 dkf Exp $
+ * RCS: @(#) $Id: tclBasic.c,v 1.162 2005/06/21 18:33:02 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -2683,6 +2683,7 @@ CallCommandTraces(iPtr, cmdPtr, oldName, newName, flags)
 
     result = NULL;
     active.nextPtr = iPtr->activeCmdTracePtr;
+    active.reverseScan = 0;
     iPtr->activeCmdTracePtr = &active;
 
     if (flags & TCL_TRACE_DELETE) {
diff --git a/generic/tclInt.h b/generic/tclInt.h
index db8591b..aaef1a9 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 1.236 2005/06/18 21:45:02 das Exp $
+ * RCS: @(#) $Id: tclInt.h,v 1.237 2005/06/21 18:33:04 dgp Exp $
  */
 
 #ifndef _TCLINT
@@ -385,6 +385,8 @@ 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 traces
+				 * are scanning in reverse order. */
 } ActiveCommandTrace;
 
 /*
@@ -796,6 +798,8 @@ 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 traces
+				 * are scanning in reverse order. */
 } ActiveInterpTrace;
 
 /*
diff --git a/generic/tclTrace.c b/generic/tclTrace.c
index d482a6b..c3aaa82 100644
--- a/generic/tclTrace.c
+++ b/generic/tclTrace.c
@@ -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: tclTrace.c,v 1.24 2005/06/14 13:46:03 dkf Exp $
+ * RCS: @(#) $Id: tclTrace.c,v 1.25 2005/06/21 18:33:05 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -1176,7 +1176,11 @@ 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) {
@@ -1395,6 +1399,7 @@ 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) {
@@ -1402,6 +1407,7 @@ TclCheckExecutionTraces(interp, command, numChars, cmdPtr, code,
 	        tracePtr = tracePtr->nextPtr;
             }
         } else {
+	    active.reverseScan = 0;
 	    active.nextTracePtr = tracePtr->nextPtr;
         }
 	tcmdPtr = (TraceCommandInfo*)tracePtr->clientData;
@@ -1418,7 +1424,9 @@ TclCheckExecutionTraces(interp, command, numChars, cmdPtr, code,
 	        ckfree((char*)tcmdPtr);
 	    }
 	}
-        lastTracePtr = tracePtr;
+	if (active.nextTracePtr) {
+	    lastTracePtr = active.nextTracePtr->nextPtr;
+	}
     }
     iPtr->activeCmdTracePtr = active.nextPtr;
     if (state) {
@@ -1493,6 +1501,7 @@ 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) {
@@ -1500,6 +1509,7 @@ TclCheckInterpTraces(interp, command, numChars, cmdPtr, code,
 	        tracePtr = tracePtr->nextPtr;
             }
         } else {
+	    active.reverseScan = 0;
 	    active.nextTracePtr = tracePtr->nextPtr;
         }
 	if (tracePtr->level > 0 && curLevel > tracePtr->level) {
@@ -1547,7 +1557,9 @@ 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;
     if (state) {
@@ -2219,15 +2231,18 @@ 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;
 
     /*
      * Locate the trace entry in the interpreter's trace list,
      * and remove it from the list.
      */
 
+    prevPtr = NULL;
     while ((*tracePtr2) != NULL && (*tracePtr2) != tracePtr) {
+	prevPtr = *tracePtr2;
 	tracePtr2 = &((*tracePtr2)->nextPtr);
     }
     if (*tracePtr2 == NULL) {
@@ -2236,6 +2251,23 @@ Tcl_DeleteTrace(interp, trace)
     (*tracePtr2) = (*tracePtr2)->nextPtr;
 
     /*
+     * The code below makes it possible to delete traces while traces
+     * are active: it makes sure that the deleted trace won't be
+     * processed by TclCheckInterpTraces.
+     */
+
+    for (activePtr = iPtr->activeInterpTracePtr;  activePtr != NULL;
+	    activePtr = activePtr->nextPtr) {
+	if (activePtr->nextTracePtr == tracePtr) {
+	    if (activePtr->reverseScan) {
+		activePtr->nextTracePtr = prevPtr;
+	    } else {
+		activePtr->nextTracePtr = tracePtr->nextPtr;
+	    }
+	}
+    }
+
+    /*
      * If the trace forbids bytecode compilation, change the interpreter's
      * state.  If bytecode compilation is now permitted, flag the fact and
      * advance the compilation epoch so that procs will be recompiled to
diff --git a/tests/trace.test b/tests/trace.test
index e8b2ae7..d4a777f 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 1.37 2004/11/15 21:47:23 dgp Exp $
+# RCS: @(#) $Id: trace.test,v 1.38 2005/06/21 18:33:05 dgp Exp $
 
 if {[lsearch [namespace children] ::tcltest] == -1} {
     package require tcltest
@@ -2204,7 +2204,40 @@ test trace-33.1 {variable match with remove variable} {
     llength [trace info variable x]
 } 0
 
-test trace-34.1 {527164: Keep -errorinfo of traces} -setup {
+test trace-34.1 {Bug 1201035} {
+    set ::x [list]
+    proc foo {} {lappend ::x foo}
+    proc bar args {
+        lappend ::x $args
+        trace remove execution foo leavestep bar
+        trace remove execution foo enterstep bar
+        trace add execution foo leavestep bar
+        trace add execution foo enterstep bar
+        lappend ::x done
+    }
+    trace add execution foo leavestep bar
+    trace add execution foo enterstep bar
+    foo
+    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
+} {}
+
+test trace-35.1 {527164: Keep -errorinfo of traces} -setup {
     unset -nocomplain x y
 } -body {
     trace add variable x write {error foo;#}