patch 9.1.0451: No test for escaping '<' with shellescape()

Problem:  No test for escaping '<' with shellescape()
Solution: Add a test.  Use memcpy() in code to make it easier to
          understand.  Fix a typo (zeertzjq).

closes: #14876

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/strings.c

@@ -269,12 +269,12 @@ vim_strsave_shellescape(char_u *string, int do_special, int do_newline)
 		*d++ = *p++;
 		continue;
 	    }
-	    if (do_special && find_cmdline_var(p, &l) >= 0 && l > 0)
+	    if (do_special && find_cmdline_var(p, &l) >= 0)
 	    {
 		*d++ = '\\';		// insert backslash
-		do			// copy the var
-		    *d++ = *p++;
-		while (--l > 0);
+		memcpy(d, p, l);	// copy the var
+		d += l;
+		p += l;
 		continue;
 	    }
 	    if (*p == '\\' && fish_like)

src/structs.h

@@ -4795,7 +4795,7 @@ typedef struct soffset
 typedef struct spat
 {
     char_u	    *pat;	// the pattern (in allocated memory) or NULL
-    size_t	    patlen;	// the length of the patten (0 is pat is NULL)
+    size_t	    patlen;	// the length of the pattern (0 if pat is NULL)
     int		    magic;	// magicness of the pattern
     int		    no_scs;	// no smartcase for this pattern
     soffset_T	    off;

src/testdir/test_shell.vim

@@ -158,6 +158,10 @@ func Test_shellescape()
   call assert_equal("'te\\#xt'", shellescape("te#xt", 1))
   call assert_equal("'te!xt'", shellescape("te!xt"))
   call assert_equal("'te\\!xt'", shellescape("te!xt", 1))
+  call assert_equal("'te<cword>xt'", shellescape("te<cword>xt"))
+  call assert_equal("'te\\<cword>xt'", shellescape("te<cword>xt", 1))
+  call assert_equal("'te<cword>%xt'", shellescape("te<cword>%xt"))
+  call assert_equal("'te\\<cword>\\%xt'", shellescape("te<cword>%xt", 1))
 
   call assert_equal("'te\nxt'", shellescape("te\nxt"))
   call assert_equal("'te\\\nxt'", shellescape("te\nxt", 1))

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    451,
 /**/
     450,
 /**/