Work in progress

src/tightdb/group.cpp

@@ -430,15 +430,15 @@ void Group::remove_table(size_t table_ndx)
     // columns of other tables, however, to do that, we would have to
     // automatically remove the "offending" link columns from those other
     // tables. Such a behaviour is deemed too obscure, and we shall therefore
-    // require that a removed table does not contain foreigh origin backlink
-    // columns.
+    // require that a removed table does not contain any backlinks columns whose
+    // origin table is not the removed table.
     typedef _impl::TableFriend tf;
     if (tf::is_cross_table_link_target(*table))
         throw CrossTableLinkTarget();
 
     // There is no easy way for Group::TransactAdvancer to handle removal of
     // tables that contain foreign target table link columns, because that
-    // involves removal of the corresponding backlink columns. For that reason,
+    // involves removal of the corresponding backlink columns. For this reason,
     // we start by removing all columns, which will generate individual
     // replication instructions for each column removal with sufficient
     // information for Group::TransactAdvancer to handle them.

src/tightdb/replication.hpp

@@ -899,8 +899,8 @@ inline void Replication::erase_column(const Descriptor& desc, std::size_t col_nd
     if (!tf::is_link_type(ColumnType(type))) {
         simple_cmd(instr_EraseColumn, util::tuple(col_ndx)); // Throws
     }
-    else { // it's a link column:
-
+    else {
+        // Link column
         TIGHTDB_ASSERT(desc.is_root());
         typedef _impl::DescriptorFriend df;
         const Table& origin_table = df::get_root_table(desc);

src/tightdb/table.cpp

@@ -674,9 +674,9 @@ void Table::do_erase_column(Descriptor& desc, size_t col_ndx)
     // the column removal to correctly reproduce the desired effect, namely that
     // the table appears truncated after the removal of the last non-hidden
     // column. The clear operation needs to be submitted to the replication
-    // handler as an individual operation, and precede the column removal
-    // operation in order to get the right behaviour in
-    // Group::advance_transact().
+    // handler as an individual operationin order to get the right behaviour in
+    // Group::advance_transact(). This ensures that origin tables for cleared
+    // backlink columns are marked dirty.
     if (desc.is_root()) {
         if (root_table.m_spec.get_public_column_count() == 1 && root_table.m_cols.size() > 1)
             root_table.clear(); // Throws

test/test_links.cpp

@@ -973,11 +973,37 @@ TEST(Links_CascadeRemove_ColumnLink)
     target_row_1 = target->get(1);
     origin_row_1.set_link(0,1); // origin[1].o_1 -> target[1]
 
-    // Break link by clearing table
+    // Break links by clearing table
     CHECK(origin_row_0.get_link(0) == 0 && origin_row_1.get_link(0) == 1);
     CHECK(target_row_0 && target_row_1);
     origin->clear();
     CHECK(!target_row_0 && !target_row_1);
+    CHECK(target->is_empty());
+    origin->add_empty_row(2);
+    target->add_empty_row(2);
+    origin_row_0 = origin->get(0);
+    origin_row_1 = origin->get(1);
+    target_row_0 = target->get(0);
+    target_row_1 = target->get(1);
+    origin_row_0.set_link(0,0); // origin[0].o_1 -> target[0]
+    origin_row_1.set_link(0,1); // origin[1].o_1 -> target[1]
+
+    // Break links by link column removal
+    CHECK(origin_row_0.get_link(0) == 0 && origin_row_1.get_link(0) == 1);
+    CHECK(target_row_0 && target_row_1);
+    origin->remove_column(0);
+    CHECK(!target_row_0 && !target_row_1);
+    CHECK(target->is_empty());
+    origin->add_column_link(type_Link, "o_1", *target, link_Strong);
+    origin_row_0.set_link(0,0); // origin[0].o_1 -> target[0]
+    origin_row_1.set_link(0,1); // origin[1].o_1 -> target[1]
+
+    // Break links by removal of origin table
+    CHECK(origin_row_0.get_link(0) == 0 && origin_row_1.get_link(0) == 1);
+    CHECK(target_row_0 && target_row_1);
+    group.remove_table("origin");
+    CHECK(!target_row_0 && !target_row_1);
+    CHECK(target->is_empty());
 }
 
 
@@ -1057,7 +1083,7 @@ TEST(Links_CascadeRemove_ColumnLinkList)
     link_list_1->add(0); // origin[1].o_1 -> [ target[0] ]
     link_list_1->add(1); // origin[1].o_1 -> [ target[0], target[1] ]
 
-    // Break link by clearing table
+    // Break links by clearing table
     CHECK(link_list_0->size() == 1 && link_list_0->get(0).get_index() == 0);
     CHECK(link_list_1->size() == 2 && link_list_1->get(0).get_index() == 0 &&
           link_list_1->get(1).get_index() == 1);
@@ -1072,6 +1098,11 @@ TEST(Links_CascadeRemove_MultiLevel)
 }
 
 
+TEST(Links_CascadeRemove_SameOriginAndTargetTable)
+{
+}
+
+
 TEST(Links_CascadeRemove_Cycles)
 {
 }