Don't render field in search result if it is empty after matched elements filtering.

7 files changed, 89 insertions, 74 deletions

diff --git a/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp b/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp
index a00592400b5..8bf3db4d112 100644
--- a/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp
+++ b/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp
@@ -131,7 +131,7 @@ TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_corr
 {
     set_field("array", true);
     assertWritten("[ { name: 'n1.2', val: 11}]", 1);
-    assertWritten("[ ]", 2);
+    assertWritten("null", 2);
     assertWritten("[ { fval: 130.0, name: 'n3.1', val: 30} ]", 3);
     assertWritten("[ { fval: 141.0, name: 'n4.2', val:  41} ]", 4);
     assertWritten("null", 5);
@@ -141,7 +141,7 @@ TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_corr
 {
     set_field("smap", true);
     assertWritten("[ { key: 'k1.2', value: { name: 'n1.2', val: 11} }]", 1);
-    assertWritten("[ ]", 2);
+    assertWritten("null", 2);
     assertWritten("[ { key: 'k3.1', value: { fval: 130.0, name: 'n3.1', val: 30} } ]", 3);
     assertWritten("[ { key: 'k4.2', value: { fval: 141.0, name: 'n4.2', val:  41} } ]", 4);
     assertWritten("null", 5);
@@ -151,7 +151,7 @@ TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_corr
 {
     set_field("map", true);
     assertWritten("[ { key: 'k1.2', value: 'n1.2'}]", 1);
-    assertWritten("[ ]", 2);
+    assertWritten("null", 2);
     assertWritten("[ { key: 'k3.1', value: 'n3.1' } ]", 3);
     assertWritten("[ { key: 'k4.2', value: 'n4.2' } ]", 4);
     assertWritten("null", 5);
diff --git a/searchsummary/src/tests/docsummary/attributedfw/attributedfw_test.cpp b/searchsummary/src/tests/docsummary/attributedfw/attributedfw_test.cpp
index 42443cf1058..e9d00629d6f 100644
--- a/searchsummary/src/tests/docsummary/attributedfw/attributedfw_test.cpp
+++ b/searchsummary/src/tests/docsummary/attributedfw/attributedfw_test.cpp
@@ -135,19 +135,19 @@ TEST_F(AttributeDFWTest, matched_elements_fields_is_populated)
 TEST_F(AttributeDFWTest, filteres_matched_elements_in_array_attribute)
 {
     setup("array_str", true);
-    expect_filtered({}, "[]");
+    expect_filtered({}, "null");
     expect_filtered({0}, "[ 'a' ]");
     expect_filtered({1, 2}, "[ 'b', 'c' ]");
-    expect_filtered({3}, "[]");
+    expect_filtered({3}, "null");
 }
 
 TEST_F(AttributeDFWTest, filteres_matched_elements_in_wset_attribute)
 {
     setup("wset_str", true);
-    expect_filtered({}, "[]");
+    expect_filtered({}, "null");
     expect_filtered({0}, "[ {'item':'a', 'weight':1} ]");
     expect_filtered({1, 2}, "[ {'item':'b', 'weight':1}, {'item':'c', 'weight':1} ]");
-    expect_filtered({3}, "[]");
+    expect_filtered({3}, "null");
 }
 
 GTEST_MAIN_RUN_ALL_TESTS()
diff --git a/searchsummary/src/tests/docsummary/matched_elements_filter/matched_elements_filter_test.cpp b/searchsummary/src/tests/docsummary/matched_elements_filter/matched_elements_filter_test.cpp
index d002a9a2748..519961dedb6 100644
--- a/searchsummary/src/tests/docsummary/matched_elements_filter/matched_elements_filter_test.cpp
+++ b/searchsummary/src/tests/docsummary/matched_elements_filter/matched_elements_filter_test.cpp
@@ -247,14 +247,14 @@ MatchedElementsFilterTest::~MatchedElementsFilterTest() = default;
 
 TEST_F(MatchedElementsFilterTest, filters_elements_in_array_field_value)
 {
-    expect_filtered("array", {}, "[]");
+    expect_filtered("array", {}, "null");
     expect_filtered("array", {0}, "[{'name':'a','weight':3}]");
     expect_filtered("array", {1}, "[{'name':'b','weight':5}]");
     expect_filtered("array", {2}, "[{'name':'c','weight':7}]");
     expect_filtered("array", {0, 1, 2}, "[{'name':'a','weight':3},"
                                         "{'name':'b','weight':5},"
                                         "{'name':'c','weight':7}]");
-    expect_filtered("array", {0, 1, 100}, "[]");
+    expect_filtered("array", {0, 1, 100}, "null");
     set_empty_values();
     expect_filtered("array", {}, "null");
     set_skip_set_values();
@@ -271,14 +271,14 @@ TEST_F(MatchedElementsFilterTest, matching_elements_fields_is_setup_for_array_fi
 
 TEST_F(MatchedElementsFilterTest, filters_elements_in_map_field_value)
 {
-    expect_filtered("map", {}, "[]");
+    expect_filtered("map", {}, "null");
     expect_filtered("map", {0}, "[{'key':'a','value':{'name':'a','weight':3}}]");
     expect_filtered("map", {1}, "[{'key':'b','value':{'name':'b','weight':5}}]");
     expect_filtered("map", {2}, "[{'key':'c','value':{'name':'c','weight':7}}]");
     expect_filtered("map", {0, 1, 2}, "[{'key':'a','value':{'name':'a','weight':3}},"
                                       "{'key':'b','value':{'name':'b','weight':5}},"
                                       "{'key':'c','value':{'name':'c','weight':7}}]");
-    expect_filtered("map", {0, 1, 100}, "[]");
+    expect_filtered("map", {0, 1, 100}, "null");
     set_empty_values();
     expect_filtered("map", {}, "null");
     set_skip_set_values();
@@ -287,12 +287,12 @@ TEST_F(MatchedElementsFilterTest, filters_elements_in_map_field_value)
 
 TEST_F(MatchedElementsFilterTest, filter_elements_in_weighed_set_field_value)
 {
-    expect_filtered("wset", {}, "[]");
+    expect_filtered("wset", {}, "null");
     expect_filtered("wset", {0}, "[{'item':'a','weight':13}]");
     expect_filtered("wset", {1}, "[{'item':'b','weight':15}]");
     expect_filtered("wset", {2}, "[{'item':'c','weight':17}]");
     expect_filtered("wset", {0, 1, 2}, "[{'item':'a','weight':13},{'item':'b','weight':15},{'item':'c','weight':17}]");
-    expect_filtered("wset", {0, 1, 100}, "[]");
+    expect_filtered("wset", {0, 1, 100}, "null");
     set_empty_values();
     expect_filtered("wset", {}, "null");
     set_skip_set_values();
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp b/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp
index 772df12b13e..e1f26f85ecd 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp
@@ -85,9 +85,12 @@ ArrayAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime::Ins
     if (elems == 0) {
         return;
     }
-    Cursor &arr = target.insertArray();
     if (_matching_elements != nullptr) {
         auto &elements = _matching_elements->get_matching_elements(docId, _field_name);
+        if (elements.empty() || elements.back() >= elems) {
+            return;
+        }
+        Cursor &arr = target.insertArray();
         auto elements_iterator = elements.cbegin();
         for (uint32_t idx = 0; idx < elems && elements_iterator != elements.cend(); ++idx) {
             assert(*elements_iterator >= idx);
@@ -97,6 +100,7 @@ ArrayAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime::Ins
             }
         }
     } else {
+        Cursor &arr = target.insertArray();
         for (uint32_t idx = 0; idx < elems; ++idx) {
             insert_element(idx, arr);
         }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/attributedfw.cpp b/searchsummary/src/vespa/searchsummary/docsummary/attributedfw.cpp
index 6d59ac4fa3b..ce08da7f7f1 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/attributedfw.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/attributedfw.cpp
@@ -197,27 +197,28 @@ MultiAttrDFWState<MultiValueType>::insertField(uint32_t docid, Inserter& target)
     if (elements.empty()) {
         return;
     }
-    Cursor &arr = target.insertArray(elements.size());
-
     if (_matching_elements) {
         const auto& matching_elems = _matching_elements->get_matching_elements(docid, _field_name);
-        if (!matching_elems.empty() && matching_elems.back() < elements.size()) {
-            if constexpr (multivalue::is_WeightedValue_v<MultiValueType>) {
-                Symbol itemSymbol = arr.resolve(ITEM);
-                Symbol weightSymbol = arr.resolve(WEIGHT);
-                for (uint32_t id_to_keep : matching_elems) {
-                    auto& element = elements[id_to_keep];
-                    Cursor& elemC = arr.addObject();
-                    set_value<ValueType>(element.value(), itemSymbol, elemC);
-                    elemC.setLong(weightSymbol, element.weight());
-                }
-            } else {
-                for (uint32_t id_to_keep : matching_elems) {
-                    append_value<ValueType>(elements[id_to_keep], arr);
-                }
+        if (matching_elems.empty() || matching_elems.back() >= elements.size()) {
+            return;
+        }
+        Cursor &arr = target.insertArray(elements.size());
+        if constexpr (multivalue::is_WeightedValue_v<MultiValueType>) {
+            Symbol itemSymbol = arr.resolve(ITEM);
+            Symbol weightSymbol = arr.resolve(WEIGHT);
+            for (uint32_t id_to_keep : matching_elems) {
+                auto& element = elements[id_to_keep];
+                Cursor& elemC = arr.addObject();
+                set_value<ValueType>(element.value(), itemSymbol, elemC);
+                elemC.setLong(weightSymbol, element.weight());
+            }
+        } else {
+            for (uint32_t id_to_keep : matching_elems) {
+                append_value<ValueType>(elements[id_to_keep], arr);
             }
         }
     } else {
+        Cursor &arr = target.insertArray(elements.size());
         if constexpr (multivalue::is_WeightedValue_v<MultiValueType>) {
             Symbol itemSymbol = arr.resolve(ITEM);
             Symbol weightSymbol = arr.resolve(WEIGHT);
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp b/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp
index 2eb79b720ad..f641b0a433d 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp
@@ -102,9 +102,12 @@ StructMapAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime:
     if (elems == 0) {
         return;
     }
-    Cursor &arr = target.insertArray();
     if (_matching_elements != nullptr) {
         auto &elements = _matching_elements->get_matching_elements(docId, _field_name);
+        if (elements.empty() || elements.back() >= elems) {
+            return;
+        }
+        Cursor &arr = target.insertArray();
         auto elements_iterator = elements.cbegin();
         for (uint32_t idx = 0; idx < elems && elements_iterator != elements.cend(); ++idx) {
             assert(*elements_iterator >= idx);
@@ -114,6 +117,7 @@ StructMapAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime:
             }
         }
     } else {
+        Cursor &arr = target.insertArray();
         for (uint32_t idx = 0; idx < elems; ++idx) {
             insert_element(idx, arr);
         }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/summaryfieldconverter.cpp b/searchsummary/src/vespa/searchsummary/docsummary/summaryfieldconverter.cpp
index d09f23251e7..0542423ab75 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/summaryfieldconverter.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/summaryfieldconverter.cpp
@@ -372,6 +372,11 @@ private:
         return _matching_elems != nullptr;
     }
 
+    template <typename Value>
+    bool empty_or_empty_after_filtering(const Value& value) const {
+        return (value.isEmpty() || (filter_matching_elements() && (_matching_elems->empty() || _matching_elems->back() >= value.size())));
+    }
+
     void visit(const AnnotationReferenceFieldValue & v ) override {
         (void)v;
         Cursor &c = _inserter.insertObject();
@@ -388,14 +393,15 @@ private:
     }
 
     void visit(const MapFieldValue & v) override {
+        if (empty_or_empty_after_filtering(v)) {
+            return;
+        }
         MapFieldValueInserter map_inserter(_inserter, _tokenize);
         if (filter_matching_elements()) {
             assert(v.has_no_erased_keys());
-            if (!_matching_elems->empty() && _matching_elems->back() < v.size()) {
-                for (uint32_t id_to_keep : (*_matching_elems)) {
-                    auto entry = v[id_to_keep];
-                    map_inserter.insert_entry(*entry.first, *entry.second);
-                }
+            for (uint32_t id_to_keep : (*_matching_elems)) {
+                auto entry = v[id_to_keep];
+                map_inserter.insert_entry(*entry.first, *entry.second);
             }
         } else {
             for (const auto &entry : v) {
@@ -405,20 +411,19 @@ private:
     }
 
     void visit(const ArrayFieldValue &value) override {
+        if (empty_or_empty_after_filtering(value)) {
+            return;
+        }
         Cursor &a = _inserter.insertArray();
-        if (value.size() > 0) {
-            ArrayInserter ai(a);
-            SlimeFiller conv(ai, _tokenize);
-            if (filter_matching_elements()) {
-                if (!_matching_elems->empty() && _matching_elems->back() < value.size()) {
-                    for (uint32_t id_to_keep : (*_matching_elems)) {
-                        value[id_to_keep].accept(conv);
-                    }
-                }
-            } else {
-                for (const FieldValue &fv : value) {
-                    fv.accept(conv);
-                }
+        ArrayInserter ai(a);
+        SlimeFiller conv(ai, _tokenize);
+        if (filter_matching_elements()) {
+            for (uint32_t id_to_keep : (*_matching_elems)) {
+                value[id_to_keep].accept(conv);
+            }
+        } else {
+            for (const FieldValue &fv : value) {
+                fv.accept(conv);
             }
         }
     }
@@ -503,35 +508,36 @@ private:
     }
 
     void visit(const WeightedSetFieldValue &value) override {
+        if (empty_or_empty_after_filtering(value)) {
+            return;
+        }
         Cursor &a = _inserter.insertArray();
-        if (value.size() > 0) {
-            Symbol isym = a.resolve("item");
-            Symbol wsym = a.resolve("weight");
-            using matching_elements_iterator_type = std::vector<uint32_t>::const_iterator;
-            matching_elements_iterator_type matching_elements_itr;
-            matching_elements_iterator_type matching_elements_itr_end;
+        Symbol isym = a.resolve("item");
+        Symbol wsym = a.resolve("weight");
+        using matching_elements_iterator_type = std::vector<uint32_t>::const_iterator;
+        matching_elements_iterator_type matching_elements_itr;
+        matching_elements_iterator_type matching_elements_itr_end;
+        if (filter_matching_elements()) {
+            matching_elements_itr = _matching_elems->begin();
+            matching_elements_itr_end = _matching_elems->end();
+        }
+        uint32_t idx = 0;
+        for (const auto & entry : value) {
             if (filter_matching_elements()) {
-                matching_elements_itr = (!_matching_elems->empty() && _matching_elems->back() < value.size()) ? _matching_elems->begin() : _matching_elems->end();
-                matching_elements_itr_end = _matching_elems->end();
-            }
-            uint32_t idx = 0;
-            for (const auto & entry : value) {
-                if (filter_matching_elements()) {
-                    if (matching_elements_itr == matching_elements_itr_end ||
-                        idx < *matching_elements_itr) {
-                        ++idx;
-                        continue;
-                    }
-                    ++matching_elements_itr;
+                if (matching_elements_itr == matching_elements_itr_end ||
+                    idx < *matching_elements_itr) {
+                    ++idx;
+                    continue;
                 }
-                Cursor &o = a.addObject();
-                ObjectSymbolInserter ki(o, isym);
-                SlimeFiller conv(ki, _tokenize);
-                entry.first->accept(conv);
-                int weight = static_cast<const IntFieldValue &>(*entry.second).getValue();
-                o.setLong(wsym, weight);
-                ++idx;
+                ++matching_elements_itr;
             }
+            Cursor &o = a.addObject();
+            ObjectSymbolInserter ki(o, isym);
+            SlimeFiller conv(ki, _tokenize);
+            entry.first->accept(conv);
+            int weight = static_cast<const IntFieldValue &>(*entry.second).getValue();
+            o.setLong(wsym, weight);
+            ++idx;
         }
     }