patch 8.2.2890: text property duplicated when data block splits

Problem:    Text property duplicated when data block splits.
Solution:   Do not continue text prop from previous line. (closes #8261)

src/memline.c

@@ -2772,7 +2772,8 @@ ml_append_int(
 	len = (colnr_T)STRLEN(line) + 1;	// space needed for the text
 
 #ifdef FEAT_PROP_POPUP
-    if (curbuf->b_has_textprop && lnum > 0 && !(flags & ML_APPEND_UNDO))
+    if (curbuf->b_has_textprop && lnum > 0
+			     && !(flags & (ML_APPEND_UNDO | ML_APPEND_NOPROP)))
 	// Add text properties that continue from the previous line.
 	add_text_props_for_append(buf, lnum, &line, &len, &tofree);
 #endif
@@ -3992,7 +3993,11 @@ ml_flush_line(buf_T *buf)
 		 */
 		// How about handling errors???
 		(void)ml_append_int(buf, lnum, new_line, new_len,
-			 (dp->db_index[idx] & DB_MARKED) ? ML_APPEND_MARK : 0);
+			 ((dp->db_index[idx] & DB_MARKED) ? ML_APPEND_MARK : 0)
+#ifdef FEAT_PROP_POPUP
+			     | ML_APPEND_NOPROP
+#endif
+			 );
 		(void)ml_delete_int(buf, lnum, 0);
 	    }
 	}

src/structs.h

@@ -774,6 +774,7 @@ typedef struct memline
 #define ML_APPEND_NEW	    1	// starting to edit a new file
 #define ML_APPEND_MARK	    2	// mark the new line
 #define ML_APPEND_UNDO	    4	// called from undo
+#define ML_APPEND_NOPROP    8	// do not continue textprop from previous line
 
 
 /*

src/testdir/test_textprop.vim

@@ -1469,5 +1469,24 @@ func Test_prop_one_line_window()
   bwipe!
 endfunc
 
+" This was calling ml_append_int() and copy a text property from a previous
+" line at the wrong moment.  Exact text length matters.
+def Test_prop_splits_data_block()
+  new
+  var lines: list<string> = [repeat('x', 35)]->repeat(41)
+			+ [repeat('!', 35)]
+			+ [repeat('x', 35)]->repeat(56)
+  lines->setline(1)
+  prop_type_add('someprop', {highlight: 'ErrorMsg'})
+  prop_add(1, 27, {end_lnum: 1, end_col: 70, type: 'someprop'})
+  prop_remove({type: 'someprop'}, 1)
+  prop_add(35, 22, {end_lnum: 43, end_col: 43, type: 'someprop'})
+  prop_remove({type: 'someprop'}, 35, 43)
+  assert_equal([], prop_list(42))
+
+  bwipe!
+  prop_type_delete('someprop')
+enddef
+
 
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2890,
 /**/
     2889,
 /**/