3389764 Eliminate possibility that "path" value dup can create reference cycle.

2 files changed, 17 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index 54a718c..bbe93e8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2011-08-12  Don Porter  <dgp@users.sourceforge.net>
+
+	* generic/tclPathObj.c:	[Bug 3389764] Eliminate possibility that dup
+	of a "path" value can create reference cycle.
+
 2011-08-09  Jan Nijtmans  <nijtmans@users.sf.net>
 
 	* win/tclWinConsole.c: [Bug 3388350] mingw64 compiler warnings
diff --git a/generic/tclPathObj.c b/generic/tclPathObj.c
index da3b280..8840e4a 100644
--- a/generic/tclPathObj.c
+++ b/generic/tclPathObj.c
@@ -2669,29 +2669,29 @@ DupFsPathInternalRep(
 
     SETPATHOBJ(copyPtr, copyFsPathPtr);
 
-    if (srcFsPathPtr->translatedPathPtr != NULL) {
+    if (srcFsPathPtr->translatedPathPtr == srcPtr) {
+	/* Cycle in src -> make cycle in copy. */
+	copyFsPathPtr->translatedPathPtr = copyPtr;
+    } else {
 	copyFsPathPtr->translatedPathPtr = srcFsPathPtr->translatedPathPtr;
-	if (copyFsPathPtr->translatedPathPtr != copyPtr) {
+	if (copyFsPathPtr->translatedPathPtr != NULL) {
 	    Tcl_IncrRefCount(copyFsPathPtr->translatedPathPtr);
 	}
-    } else {
-	copyFsPathPtr->translatedPathPtr = NULL;
     }
 
-    if (srcFsPathPtr->normPathPtr != NULL) {
+    if (srcFsPathPtr->normPathPtr == srcPtr) {
+	/* Cycle in src -> make cycle in copy. */
+	copyFsPathPtr->normPathPtr = copyPtr;
+    } else {
 	copyFsPathPtr->normPathPtr = srcFsPathPtr->normPathPtr;
-	if (copyFsPathPtr->normPathPtr != copyPtr) {
+	if (copyFsPathPtr->normPathPtr != NULL) {
 	    Tcl_IncrRefCount(copyFsPathPtr->normPathPtr);
 	}
-    } else {
-	copyFsPathPtr->normPathPtr = NULL;
     }
 
-    if (srcFsPathPtr->cwdPtr != NULL) {
-	copyFsPathPtr->cwdPtr = srcFsPathPtr->cwdPtr;
+    copyFsPathPtr->cwdPtr = srcFsPathPtr->cwdPtr;
+    if (copyFsPathPtr->cwdPtr != NULL) {
 	Tcl_IncrRefCount(copyFsPathPtr->cwdPtr);
-    } else {
-	copyFsPathPtr->cwdPtr = NULL;
     }
 
     copyFsPathPtr->flags = srcFsPathPtr->flags;