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-rw-r--r--generic/tclListObj.c19
-rw-r--r--generic/tclUtil.c17
2 files changed, 35 insertions, 1 deletions
diff --git a/generic/tclListObj.c b/generic/tclListObj.c
index 786e1ce..e42567e 100644
--- a/generic/tclListObj.c
+++ b/generic/tclListObj.c
@@ -1990,7 +1990,21 @@ UpdateStringOfList(
* Pass 2: copy into string rep buffer.
*/
+ /*
+ * We used to set the string length here, relying on a presumed
+ * guarantee that the number of bytes TclScanElement() calls reported
+ * to be needed was a precise count and not an over-estimate, so long
+ * as the same flag values were passed to TclConvertElement().
+ *
+ * Then we saw [35a8f1c04a], where a bug in TclScanElement() caused
+ * that guarantee to fail. Rather than trust there are no more bugs,
+ * we set the length after the loop based on what was actually written,
+ * an not on what was predicted.
+ *
listPtr->length = bytesNeeded - 1;
+ *
+ */
+
listPtr->bytes = ckalloc(bytesNeeded);
dst = listPtr->bytes;
for (i = 0; i < numElems; i++) {
@@ -1999,7 +2013,10 @@ UpdateStringOfList(
dst += TclConvertElement(elem, length, dst, flagPtr[i]);
*dst++ = ' ';
}
- listPtr->bytes[listPtr->length] = '\0';
+ dst[-1] = '\0';
+
+ /* Here is the safe setting of the string length. */
+ listPtr->length = dst - 1 - listPtr->bytes;
if (flagPtr != localFlags) {
ckfree(flagPtr);
diff --git a/generic/tclUtil.c b/generic/tclUtil.c
index 6eab7b8..d5cc7c2 100644
--- a/generic/tclUtil.c
+++ b/generic/tclUtil.c
@@ -1046,6 +1046,23 @@ TclScanElement(
return 2;
}
+#if COMPAT
+ /*
+ * We have an established history in TclConvertElement() when quoting
+ * because of a leading hash character to force what would be the
+ * CONVERT_MASK mode into the CONVERT_BRACE mode. That is, we format
+ * the element #{a"b} like this:
+ * {#{a"b}}
+ * and not like this:
+ * \#{a\"b}
+ * This is inconsistent with [list x{a"b}], but we will not change that now.
+ * Set that preference here so that we compute a tight size requirement.
+ */
+ if ((*src == '#') && !(*flagPtr & TCL_DONT_QUOTE_HASH)) {
+ preferBrace = 1;
+ }
+#endif
+
if ((*p == '{') || (*p == '"')) {
/*
* Must escape or protect so leading character of value is not