patch 8.2.4722: ending recording with mapping records too much

Problem:    When a recording is ended with a mapped key that key is also
            recorded.
Solution:   Remember the previous last_recorded_len. (closes #10122)

src/getchar.c

@@ -1705,10 +1705,16 @@ vgetc(void)
     }
     else
     {
+	// number of characters recorded from the last vgetc() call
+	static int	last_vgetc_recorded_len = 0;
+
 	mod_mask = 0;
 	vgetc_mod_mask = 0;
 	vgetc_char = 0;
-	last_recorded_len = 0;
+
+	// last_recorded_len can be larger than last_vgetc_recorded_len
+	// if peeking records more
+	last_recorded_len -= last_vgetc_recorded_len;
 
 	for (;;)		// this is done twice if there are modifiers
 	{
@@ -1910,6 +1916,8 @@ vgetc(void)
 
 	    break;
 	}
+
+	last_vgetc_recorded_len = last_recorded_len;
     }
 
 #ifdef FEAT_EVAL

src/testdir/test_registers.vim

@@ -759,6 +759,27 @@ func Test_record_in_select_mode()
   bwipe!
 endfunc
 
+" mapping that ends macro recording should be removed from recorded macro
+func Test_end_record_using_mapping()
+  call setline(1, 'aaa')
+  nnoremap s q
+  call feedkeys('safas', 'tx')
+  call assert_equal('fa', @a)
+  nunmap s
+
+  nnoremap xx q
+  call feedkeys('0xxafaxx', 'tx')
+  call assert_equal('fa', @a)
+  nunmap xx
+
+  nnoremap xsx q
+  call feedkeys('0qafaxsx', 'tx')
+  call assert_equal('fa', @a)
+  nunmap xsx
+
+  bwipe!
+endfunc
+
 func Test_end_reg_executing()
   nnoremap s <Nop>
   let @a = 's'

src/version.c

@@ -746,6 +746,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    4722,
 /**/
     4721,
 /**/