From 7c824682d2028432ee082703ef0ab399867a089b Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sun, 8 May 2022 22:32:58 +0100
Subject: [PATCH] patch 8.2.4919: can add invalid bytes with :spellgood

Problem:    Can add invalid bytes with :spellgood.
Solution:   Check for a valid word string.
---
 src/errors.h                    |  4 ++++
 src/mbyte.c                     |  2 +-
 src/spellfile.c                 | 10 ++++++++++
 src/testdir/test_spell_utf8.vim |  5 +++++
 src/version.c                   |  2 ++
 5 files changed, 22 insertions(+), 1 deletion(-)

From fe978c2b6bb9d897d962595a4a51dd7a71dc8e89 Mon Sep 17 00:00:00 2001
From: Bram Moolenaar <Bram@vim.org>
Date: Sun, 8 May 2022 22:43:51 +0100
Subject: [PATCH] patch 8.2.4921: spell test fails because of new illegal byte
 check

Problem:    Spell test fails because of new illegal byte check.
Solution:   Remove the test.
---
 src/testdir/test_spell.vim | 8 --------
 src/version.c              | 2 ++
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/src/mbyte.c b/src/mbyte.c
index 2b7f9991ae14..a01a05140207 100644
--- a/src/mbyte.c
+++ b/src/mbyte.c
@@ -4047,7 +4047,7 @@ utf_find_illegal(void)
     convert_setup(&vimconv, NULL, NULL);
 }
 
-#if defined(FEAT_GUI_GTK) || defined(PROTO)
+#if defined(FEAT_GUI_GTK) || defined(FEAT_SPELL) || defined(PROTO)
 /*
  * Return TRUE if string "s" is a valid utf-8 string.
  * When "end" is NULL stop at the first NUL.
diff --git a/src/spellfile.c b/src/spellfile.c
index 22cf82da0872..f0d6d96a47f0 100644
--- a/src/spellfile.c
+++ b/src/spellfile.c
@@ -4361,6 +4361,10 @@ store_word(
     int		res = OK;
     char_u	*p;
 
+    // Avoid adding illegal bytes to the word tree.
+    if (enc_utf8 && !utf_valid_string(word, NULL))
+	return FAIL;
+
     (void)spell_casefold(word, len, foldword, MAXWLEN);
     for (p = pfxlist; res == OK; ++p)
     {
@@ -6167,6 +6171,12 @@ spell_add_word(
     int		i;
     char_u	*spf;
 
+    if (enc_utf8 && !utf_valid_string(word, NULL))
+    {
+	emsg(_("E1280: Illegal character in word"));
+	return;
+    }
+
     if (idx == 0)	    /* use internal wordlist */
     {
 	if (int_wordlist == NULL)
diff --git a/src/testdir/test_spell_utf8.vim b/src/testdir/test_spell_utf8.vim
index 79dc3e4a4a62..17fa23555818 100644
--- a/src/testdir/test_spell.vim
+++ b/src/testdir/test_spell.vim
@@ -476,16 +476,6 @@
   bwipe!
 endfunc
 
-func Test_spell_single_word()
-  set spell
-  new
-  silent! norm 0R00
-  spell! ßÂ
-  silent 0norm 0r$ Dvz=
-  set nospell
-  bwipe!
-endfunc
-
 let g:test_data_aff1 = [
       \"SET ISO8859-1",
       \"TRY esianrtolcdugmphbyfvkwjkqxz-\xEB\xE9\xE8\xEA\xEF\xEE\xE4\xE0\xE2\xF6\xFC\xFB'ESIANRTOLCDUGMPHBYFVKWJKQXZ",
@@ -936,3 +926,8 @@
       \"SAL Z                    S",
       \ ]

+" Invalid bytes may cause trouble when creating the word list.
+func Test_check_for_valid_word()
+  call assert_fails("spellgood! 0\xac", 'E1280:')
+endfunc
+
diff --git a/src/version.c b/src/version.c
index f949dd6d7ed0..c4f5655bf6c2 100644
--- a/src/version.c
+++ b/src/version.c
@@ -795,6 +795,10 @@ static char *(features[]) =
     805,
 /**/
     5024,
+/**/
+    4921,
+/**/
+    4919,
 /**/
     4899,
 /**/