patch 8.2.3992: wrong local-additions in the help with language mix

Problem:    Wrong local-additions in the help with language mix.
Solution:   Adjust how the local additions list is generated. (Hirohito
            Higashi, closes #9464)

src/help.c

@@ -818,32 +818,31 @@ fix_help_buffer(void)
 			// the same directory.
 			for (i1 = 0; i1 < fcount; ++i1)
 			{
-			    for (i2 = 0; i2 < fcount; ++i2)
+			    f1 = fnames[i1];
+			    t1 = gettail(f1);
+			    e1 = vim_strrchr(t1, '.');
+			    if (fnamecmp(e1, ".txt") != 0
+					       && fnamecmp(e1, fname + 4) != 0)
+			    {
+				// Not .txt and not .abx, remove it.
+				VIM_CLEAR(fnames[i1]);
+				continue;
+			    }
+
+			    for (i2 = i1 + 1; i2 < fcount; ++i2)
 			    {
-				if (i1 == i2)
-				    continue;
-				if (fnames[i1] == NULL || fnames[i2] == NULL)
-				    continue;
-				f1 = fnames[i1];
 				f2 = fnames[i2];
-				t1 = gettail(f1);
+				if (f2 == NULL)
+				    continue;
 				t2 = gettail(f2);
-				e1 = vim_strrchr(t1, '.');
 				e2 = vim_strrchr(t2, '.');
 				if (e1 == NULL || e2 == NULL)
 				    continue;
-				if (fnamecmp(e1, ".txt") != 0
-				    && fnamecmp(e1, fname + 4) != 0)
-				{
-				    // Not .txt and not .abx, remove it.
-				    VIM_CLEAR(fnames[i1]);
-				    continue;
-				}
 				if (e1 - f1 != e2 - f2
 					    || fnamencmp(f1, f2, e1 - f1) != 0)
 				    continue;
 				if (fnamecmp(e1, ".txt") == 0
-				    && fnamecmp(e2, fname + 4) == 0)
+					       && fnamecmp(e2, fname + 4) == 0)
 				    // use .abx instead of .txt
 				    VIM_CLEAR(fnames[i1]);
 			    }

src/testdir/test_help.vim

@@ -57,16 +57,42 @@ func Test_help_local_additions()
   call writefile(['*mydoc-ext.txt* my extended awesome doc'], 'Xruntime/doc/mydoc-ext.txt')
   let rtp_save = &rtp
   set rtp+=./Xruntime
-  help
+  help local-additions
-  1
+  let lines = getline(line(".") + 1, search("^$") - 1)
-  call search('mydoc.txt')
+  call assert_equal([
-  call assert_equal('|mydoc.txt| my awesome doc', getline('.'))
+  \ '|mydoc-ext.txt| my extended awesome doc',
-  1
+  \ '|mydoc.txt| my awesome doc'
-  call search('mydoc-ext.txt')
+  \ ], lines)
-  call assert_equal('|mydoc-ext.txt| my extended awesome doc', getline('.'))
+  call delete('Xruntime/doc/mydoc-ext.txt')
+  close
+
+  call mkdir('Xruntime-ja/doc', 'p')
+  call writefile(["local-additions\thelp.jax\t/*local-additions*"], 'Xruntime-ja/doc/tags-ja')
+  call writefile(['*help.txt* This is jax file', '',
+  \ 'LOCAL ADDITIONS: *local-additions*', ''], 'Xruntime-ja/doc/help.jax')
+  call writefile(['*work.txt* This is jax file'], 'Xruntime-ja/doc/work.jax')
+  call writefile(['*work2.txt* This is jax file'], 'Xruntime-ja/doc/work2.jax')
+  set rtp+=./Xruntime-ja
+
+  help local-additions@en
+  let lines = getline(line(".") + 1, search("^$") - 1)
+  call assert_equal([
+  \ '|mydoc.txt| my awesome doc'
+  \ ], lines)
+  close
+
+  help local-additions@ja
+  let lines = getline(line(".") + 1, search("^$") - 1)
+  call assert_equal([
+  \ '|mydoc.txt| my awesome doc',
+  \ '|help.txt| This is jax file',
+  \ '|work.txt| This is jax file',
+  \ '|work2.txt| This is jax file',
+  \ ], lines)
   close
 
   call delete('Xruntime', 'rf')
+  call delete('Xruntime-ja', 'rf')
   let &rtp = rtp_save
 endfunc
 

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    3992,
 /**/
     3991,
 /**/