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authordgp <dgp@users.sourceforge.net>2011-06-17 18:41:55 (GMT)
committerdgp <dgp@users.sourceforge.net>2011-06-17 18:41:55 (GMT)
commit81b1512fb78c144b75114659c12e535bf48c65d6 (patch)
tree69b34cedb247ef9754f5a5b69be4399c2fe6299f
parent12efa830f66d02509c99edcf8843347c8ec2487d (diff)
parent1fe70fb2d6b530dd2c12c5e5eb5e8d7bac9ec4b2 (diff)
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Crash in unset traces 3062331
-rw-r--r--ChangeLog6
-rw-r--r--changes1
-rw-r--r--generic/ttk/ttkTrace.c46
-rw-r--r--tests/ttk/ttk.test10
4 files changed, 63 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog
index fc8a618..e5e6e45 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2011-06-17 Don Porter <dgp@users.sourceforge.net>
+
+ * generic/ttk/ttkTrace.c: Workaround Bug 3062331.
+ * tests/ttk/ttk.test:
+ * changes: Updated
+
2011-06-16 Jan Nijtmans <nijtmans@users.sf.net>
* win/tcl.m4: Sync with win/tcl.m4 from Tcl
diff --git a/changes b/changes
index 443fd24..ab91a9f 100644
--- a/changes
+++ b/changes
@@ -6927,3 +6927,4 @@ and -to (porter)
2011-06-10 (bug fix)[3315731] fix [$entry -invcmd] (porter)
+2011-06-17 (bug fix)[3062331] crash in unset traces (macdonald,porter)
diff --git a/generic/ttk/ttkTrace.c b/generic/ttk/ttkTrace.c
index 1fb0283..fe4745f 100644
--- a/generic/ttk/ttkTrace.c
+++ b/generic/ttk/ttkTrace.c
@@ -44,6 +44,16 @@ VarTraceProc(
* If the variable is being unset, then re-establish the trace:
*/
if (flags & TCL_TRACE_DESTROYED) {
+ /*
+ * If a prior call to Ttk_UntraceVariable() left behind an
+ * indicator that we wanted this handler to be deleted (see below),
+ * cleanup the ClientData bits and exit.
+ */
+ if (tracePtr->interp == NULL) {
+ Tcl_DecrRefCount(tracePtr->varnameObj);
+ ckfree((ClientData)tracePtr);
+ return NULL;
+ }
Tcl_TraceVar(interp, name,
TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
VarTraceProc, clientData);
@@ -104,6 +114,42 @@ Ttk_TraceHandle *Ttk_TraceVariable(
void Ttk_UntraceVariable(Ttk_TraceHandle *h)
{
if (h) {
+ ClientData cd = NULL;
+
+ /*
+ * Workaround for Tcl Bug 3062331. The trace design problem is
+ * that when variable unset traces fire, Tcl documents that the
+ * traced variable has already been unset. It's already gone.
+ * So from within an unset trace, if you try to call
+ * Tcl_UntraceVar() on that variable, it will do nothing, because
+ * the variable by that name can no longer be found. It's gone.
+ * This means callers of Tcl_UntraceVar() that might be running
+ * in response to an unset trace have to handle the possibility
+ * that their Tcl_UntraceVar() call will do nothing. In this case,
+ * we have to support the possibility that Tcl_UntraceVar() will
+ * leave the trace in place, so we need to leave the ClientData
+ * untouched so when that trace does fire it will not crash.
+ */
+
+ /*
+ * Search the traces on the variable to see if the one we are tasked
+ * with removing is present.
+ */
+ while ((cd = Tcl_VarTraceInfo(h->interp, Tcl_GetString(h->varnameObj),
+ 0, VarTraceProc, cd)) != NULL) {
+ if (cd == (ClientData) h) {
+ break;
+ }
+ }
+ /*
+ * If the trace we wish to delete is not visible, Tcl_UntraceVar
+ * will do nothing, so don't try to call it. Instead set an
+ * indicator in the Ttk_TraceHandle that we need to cleanup later.
+ */
+ if (cd == NULL) {
+ h->interp = NULL;
+ return;
+ }
Tcl_UntraceVar(h->interp, Tcl_GetString(h->varnameObj),
TCL_GLOBAL_ONLY|TCL_TRACE_WRITES|TCL_TRACE_UNSETS,
VarTraceProc, (ClientData)h);
diff --git a/tests/ttk/ttk.test b/tests/ttk/ttk.test
index ddfaf84..1eec180 100644
--- a/tests/ttk/ttk.test
+++ b/tests/ttk/ttk.test
@@ -555,6 +555,16 @@ test ttk-14.3 "-textvariable in nonexistant namespace" -body {
} -returnCodes 1 -result {can't trace *: parent namespace doesn't exist} \
-match glob -cleanup { destroy .tw }
+test ttk-15.1 {Bug 3062331} -setup {
+ destroy .b
+} -body {
+ set Y {}
+ ttk::button .b -textvariable Y
+ trace variable Y u "destroy .b"
+ unset Y
+} -cleanup {
+ destroy .b
+} -result {}
## Test ensemble processing:
#