fix moving cursor screen row down with row-wrapping tab characters

src/core/BufferView.cc

@@ -402,14 +402,20 @@ void BufferView::move_forward_to_screen_position(
         bool allow_eol)
 {
     *m_iterator = *line;
+    bool moved_to_target_row = false;
     for (auto it = horiz_iter(line); it.is_valid(); it++)
     {
-        if ((allow_eol || (!it.is_eol())) &&
+        if (((!it.is_eol()) || allow_eol) &&
                     ((it.row_offset() < target_row_offset) ||
+                     (!moved_to_target_row) ||
                      (it.screen_column() <= m_target_screen_column)))
         {
             *m_iterator = *it.iterator();
             m_cursor_row_offset = it.row_offset();
+            if (it.row_offset() == target_row_offset)
+            {
+                moved_to_target_row = true;
+            }
         }
         else
         {

test/src/test_BufferView.cc

@@ -729,3 +729,31 @@ TEST(BufferViewTest, scrolls_past_empty_lines)
     bv.update();
     EXPECT_EQ(0, LineNumber(iterator));
 }
+
+TEST(BufferViewTest, moving_cursor_screen_row_down_jumps_past_wrapped_tab)
+{
+    static const char data[] =
+        "0\n"
+        "1abc\tdefghijklmnopqrstuvwxyz\n"
+        "2\n"
+        "3\n";
+    auto b = std::make_shared<Buffer>((const uint8_t *)data, strlen(data));
+    auto iterator = b->add_cursor();
+    BufferView bv(b, iterator, Cwd);
+    bv.resize(5, 10);
+    bv.update();
+    EXPECT_EQ(C('0'), **iterator);
+    EXPECT_EQ(0, bv.cursor_screen_row());
+    bv.cursor_move(BufferView::CursorMovement::SCREEN_ROW_DOWN, false);
+    bv.update();
+    EXPECT_EQ(C('1'), **iterator);
+    EXPECT_EQ(1, bv.cursor_screen_row());
+    bv.cursor_move(BufferView::CursorMovement::SCREEN_ROW_DOWN, false);
+    bv.update();
+    EXPECT_EQ(C('d'), **iterator);
+    EXPECT_EQ(2, bv.cursor_screen_row());
+    bv.cursor_move(BufferView::CursorMovement::SCREEN_ROW_DOWN, false);
+    bv.update();
+    EXPECT_EQ(C('f'), **iterator);
+    EXPECT_EQ(3, bv.cursor_screen_row());
+}