From 884c46aadbe6a2f7203f84d4173a515ca4ccf8de Mon Sep 17 00:00:00 2001
From: Norihiro Tanaka <noritnk@kcn.ne.jp>
Date: Thu, 24 Sep 2020 10:39:46 +0900
Subject: [PATCH] grep: fix ignore-case Turkish bug

* src/grep.c (fgrep_icase_charlen): Do not assume that converting single-byte
character to upper yields a single-byte character.
* tests/turkish-eyes: Add new test cases for this changes.
---
 src/grep.c         |   29 +++++++++++++++--------------
 tests/turkish-eyes |   16 ++++++++++++++++
 2 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/src/grep.c b/src/grep.c
index 1453b14..1efaf3b 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -2310,23 +2310,24 @@ contains_encoding_error (char const *pat, size_t patlen)
 static int
 fgrep_icase_charlen (char const *pat, size_t patlen, mbstate_t *mbs)
 {
-  int n = localeinfo.sbclen[to_uchar (*pat)];
-  if (n < 0)
+  if (!localeinfo.multibyte)
+    return localeinfo.sbclen[to_uchar (*pat)];
+
+  wchar_t wc;
+  size_t wn = mbrtowc (&wc, pat, patlen, mbs);
+  wchar_t folded[CASE_FOLDED_BUFSIZE];
+
+  if (MB_LEN_MAX < wn || case_folded_counterparts (wc, folded))
+    return -1;
+
+  for (int i = wn; 0 < --i; )
     {
-      wchar_t wc;
-      wchar_t folded[CASE_FOLDED_BUFSIZE];
-      size_t wn = mbrtowc (&wc, pat, patlen, mbs);
-      if (MB_LEN_MAX < wn || case_folded_counterparts (wc, folded))
+      unsigned char c = pat[i];
+      if (toupper (c) != c)
         return -1;
-      for (int i = wn; 0 < --i; )
-        {
-          unsigned char c = pat[i];
-          if (toupper (c) != c)
-            return -1;
-        }
-      n = wn;
     }
-  return n;
+
+  return wn;
 }
 
 /* Return true if the -F patterns PAT, of size PATLEN, contain only
diff --git a/tests/turkish-eyes b/tests/turkish-eyes
index ba1ea33..d1e7978 100755
--- a/tests/turkish-eyes
+++ b/tests/turkish-eyes
@@ -43,4 +43,20 @@ for opt in -E -F -G; do
   compare out in || fail=1
 done
 
+printf "$I\n" > in || framework_failure_
+search_str=i
+
+for opt in -E -F -G; do
+  LC_ALL=$L grep $opt -io "$search_str" in > out || fail=1
+  compare out in || fail=1
+done
+
+printf "$i\n" > in || framework_failure_
+search_str=I
+
+for opt in -E -F -G; do
+  LC_ALL=$L grep $opt -io "$search_str" in > out || fail=1
+  compare out in || fail=1
+done
+
 Exit $fail
-- 
1.7.1