From 9b529e05399279d3631a9740e3b61bb19a1af5d8 Mon Sep 17 00:00:00 2001
From: dgp <dgp@users.sourceforge.net>
Date: Mon, 13 Apr 2020 15:01:38 +0000
Subject: Known bug test string-22.14 is not so hard to fix.

---
 generic/tclCmdMZ.c | 14 ++++++++++++--
 tests/string.test  |  2 +-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index d4fa4e9..6515d98 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -2396,12 +2396,22 @@ StringStartCmd(
     cur = 0;
     if (index > 0) {
 	p = Tcl_UtfAtIndex(string, index);
+
+	TclUtfToUniChar(p, &ch);
 	for (cur = index; cur >= 0; cur--) {
-	    TclUtfToUniChar(p, &ch);
+	    int delta = 0;
+	    const char *next;
+
 	    if (!Tcl_UniCharIsWordChar(ch)) {
 		break;
 	    }
-	    p = Tcl_UtfPrev(p, string);
+
+	    next = Tcl_UtfPrev(p, string);
+	    do {
+		next += delta;
+		delta = TclUtfToUniChar(next, &ch);
+	    } while (next + delta < p);
+	    p = next;
 	}
 	if (cur != index) {
 	    cur += 1;
diff --git a/tests/string.test b/tests/string.test
index 05a0623..54b9c95 100644
--- a/tests/string.test
+++ b/tests/string.test
@@ -1570,7 +1570,7 @@ test string-22.12 {string wordstart, unicode} {
 test string-22.13 {string wordstart, unicode} {
     string wordstart "\uc700\uc700 abc" 8
 } 3
-test string-22.14 {string wordstart, invalid UTF-8} knownBug {
+test string-22.14 {string wordstart, invalid UTF-8} {
     # See Bug c61818e4c9
     set demo [bytestring "abc def\xE0\xA9ghi"]
     string index $demo [string wordstart $demo 10]
-- 
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