From 6d7443bc0811a2f6b242aa87d5b8134515c40f36 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B8rgen=20Edelbo?= <jorgen.edelbo@mongodb.com>
Date: Mon, 21 Oct 2019 14:38:20 +0200
Subject: [PATCH] Fix initialization of Compare expression

Change-Id: If013cf622825a192ab00025f6b7832459b2d3550
---
 src/realm/query_engine.cpp     |  8 +++++++-
 src/realm/query_engine.hpp     |  2 ++
 src/realm/query_expression.hpp | 14 ++++++++++++++
 test/test_query.cpp            |  5 +++++
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/realm/query_engine.cpp b/src/realm/query_engine.cpp
index 681c8161559..564a9648eb4 100644
--- a/src/realm/query_engine.cpp
+++ b/src/realm/query_engine.cpp
@@ -633,7 +633,7 @@ size_t NotNode::find_first_no_overlap(size_t start, size_t end)
 ExpressionNode::ExpressionNode(std::unique_ptr<Expression> expression)
 : m_expression(std::move(expression))
 {
-    m_dD = 10.0;
+    m_dD = 100.0;
     m_dT = 50.0;
 }
 
@@ -642,6 +642,12 @@ void ExpressionNode::table_changed()
     m_expression->set_base_table(m_table.get());
 }
 
+void ExpressionNode::init()
+{
+    ParentNode::init();
+    m_dT = m_expression->init();
+}
+
 std::string ExpressionNode::describe(util::serializer::SerialisationState& state) const
 {
     if (m_expression) {
diff --git a/src/realm/query_engine.hpp b/src/realm/query_engine.hpp
index 07b7febdf7d..806bc2ad7b2 100644
--- a/src/realm/query_engine.hpp
+++ b/src/realm/query_engine.hpp
@@ -910,6 +910,7 @@ class IntegerNode<ColType, Equal> : public IntegerNodeBase<ColType> {
             IntegerNodeBase<ColType>::m_condition_column->find_all(*m_result, this->m_value, 0, realm::npos);
             m_index_get = 0;
             m_index_end = m_result->size();
+            IntegerNodeBase<ColType>::m_dT = 0;
         }
     }
 
@@ -2374,6 +2375,7 @@ class ExpressionNode : public ParentNode {
 public:
     ExpressionNode(std::unique_ptr<Expression>);
 
+    void init() override;
     size_t find_first_local(size_t start, size_t end) override;
 
     void table_changed() override;
diff --git a/src/realm/query_expression.hpp b/src/realm/query_expression.hpp
index a7835b42bc5..70ae2a0e0c9 100644
--- a/src/realm/query_expression.hpp
+++ b/src/realm/query_expression.hpp
@@ -381,6 +381,11 @@ class Expression {
     {
     }
 
+    virtual double init()
+    {
+        return 50.0; // Default dT
+    }
+
     virtual size_t find_first(size_t start, size_t end) const = 0;
     virtual void set_base_table(const Table* table) = 0;
     virtual void verify_column() const = 0;
@@ -3958,6 +3963,7 @@ inline Mixed get_mixed(const Value<T>& val)
 template <>
 inline Mixed get_mixed(const Value<RowIndex>&)
 {
+    REALM_ASSERT(false);
     return Mixed();
 }
 
@@ -3986,6 +3992,11 @@ class Compare : public Expression {
     {
         m_left->set_base_table(table);
         m_right->set_base_table(table);
+    }
+
+    double init() override
+    {
+        double dT = m_left_is_const ? 10.0 : 50.0;
         if (std::is_same<TCond, Equal>::value && m_left_is_const && m_right->has_search_index()) {
             if (m_left_value.m_storage.is_null(0)) {
                 m_matches = m_right->find_all(util::Optional<Mixed>());
@@ -4001,7 +4012,10 @@ class Compare : public Expression {
             m_has_matches = true;
             m_index_get = 0;
             m_index_end = m_matches.size();
+            dT = 0;
         }
+
+        return dT;
     }
 
     void verify_column() const override
diff --git a/test/test_query.cpp b/test/test_query.cpp
index ec96862168a..88afcbe51be 100644
--- a/test/test_query.cpp
+++ b/test/test_query.cpp
@@ -12272,11 +12272,16 @@ TEST(Query_LinksWithIndex)
     auto ll = foo->get_linklist(col_foo, ndx);
     ll->add(2);
     ll->add(4);
+
     Query q1 =
         origin->link(col_linklist).link(col_link).backlink(*foo, col_foo).column<String>(col_location) == "Fyn";
     CHECK_EQUAL(q.find(), 0);
     Query q2 = origin->link(col_linklist).link(col_link).backlink(*foo, col_foo).column<Int>(col_score) == 5;
     CHECK_EQUAL(q.find(), 0);
+
+    // Make sure that changes in the table are reflected in the query result
+    middle->set_link(col_link, 3, 1);
+    CHECK_EQUAL(q.find(), 1);
 }