[1af8de570511] Fix crash in [string replace] caused by cut-n-paste.

2 files changed, 23 insertions, 22 deletions

diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index 20504bd..065bf34 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -5605,6 +5605,17 @@ TEBCresume(
 	if (length3 - 1 == toIdx - fromIdx) {
 	    unsigned char *bytes1, *bytes2;
 
+	    /*
+	     * Flush the info in the string internal rep that refers to the
+	     * about-to-be-invalidated UTF-8 rep. This sets the 'allocated'
+	     * field of the String structure to 0 to indicate that a new
+	     * buffer needs to be allocated. This assumes that the value is
+	     * already of tclStringTypePtr type, which should be true provided
+	     * we call it after Tcl_GetUnicodeFromObj.
+	     */
+#define MarkStringInternalRepForFlush(objPtr) \
+	(((int *) ((objPtr)->internalRep.twoPtrValue.ptr1))[1] = 0)
+
 	    if (Tcl_IsShared(valuePtr)) {
 		objResultPtr = Tcl_DuplicateObj(valuePtr);
 		if (TclIsPureByteArray(objResultPtr)
@@ -5617,17 +5628,7 @@ TEBCresume(
 		    ustring2 = Tcl_GetUnicodeFromObj(value3Ptr, NULL);
 		    memcpy(ustring1 + fromIdx, ustring2,
 			    length3 * sizeof(Tcl_UniChar));
-
-		    /*
-		     * Magic! Flush the info in the string internal rep that
-		     * refers to the about-to-be-invalidated UTF-8 rep. This
-		     * sets the 'allocated' field of the String structure to 0
-		     * to indicate that a new buffer needs to be allocated.
-		     * This is safe; we know we've got a tclStringTypePtr set
-		     * at this point (post Tcl_GetUnicodeFromObj).
-		     */
-
-		    ((int *) objResultPtr->internalRep.twoPtrValue.ptr1)[1] = 0;
+		    MarkStringInternalRepForFlush(objResultPtr);
 		}
 		Tcl_InvalidateStringRep(objResultPtr);
 		TclDecrRefCount(value3Ptr);
@@ -5644,17 +5645,7 @@ TEBCresume(
 		    ustring2 = Tcl_GetUnicodeFromObj(value3Ptr, NULL);
 		    memcpy(ustring1 + fromIdx, ustring2,
 			    length3 * sizeof(Tcl_UniChar));
-
-		    /*
-		     * Magic! Flush the info in the string internal rep that
-		     * refers to the about-to-be-invalidated UTF-8 rep. This
-		     * sets the 'allocated' field of the String structure to 0
-		     * to indicate that a new buffer needs to be allocated.
-		     * This is safe; we know we've got a tclStringTypePtr set
-		     * at this point (post Tcl_GetUnicodeFromObj).
-		     */
-
-		    ((int *) objResultPtr->internalRep.twoPtrValue.ptr1)[1] = 0;
+		    MarkStringInternalRepForFlush(valuePtr);
 		}
 		Tcl_InvalidateStringRep(valuePtr);
 		TclDecrRefCount(value3Ptr);
diff --git a/tests/stringComp.test b/tests/stringComp.test
index f5ba002..77e14d6 100644
--- a/tests/stringComp.test
+++ b/tests/stringComp.test
@@ -728,6 +728,16 @@ test stringComp-14.3 {Bug 0dca3bfa8f} {
 	expr {$arg ne $argCopy}
     }} abcde
 } 1
+test stringComp-14.4 {Bug 1af8de570511} {
+    apply {{x y} {
+	# Generate an unshared string value
+	set val ""
+	for { set i 0 } { $i < $x } { incr i } {
+	    set val [format "0%s" $val]
+	}
+	string replace $val[unset val] 1 1 $y
+    }} 4 x
+} 0x00
 
 ## string tolower
 ## not yet bc