make sure empty AND/OR/ANDNOT flow estimates 0.0 regardless of input flow

3 files changed, 10 insertions, 7 deletions

diff --git a/searchlib/src/tests/queryeval/blueprint/intermediate_blueprints_test.cpp b/searchlib/src/tests/queryeval/blueprint/intermediate_blueprints_test.cpp
index ed2bfdeca6f..856ac2391f8 100644
--- a/searchlib/src/tests/queryeval/blueprint/intermediate_blueprints_test.cpp
+++ b/searchlib/src/tests/queryeval/blueprint/intermediate_blueprints_test.cpp
@@ -1289,6 +1289,7 @@ TEST("require that OR blueprint use saturated sum as estimate") {
 }
 
 void verify_relative_estimate(make &&mk, double expect) {
+    EXPECT_EQUAL(mk.making->estimate(), 0.0);
     Blueprint::UP bp = std::move(mk).leafs({200,300,950});
     bp->setDocIdLimit(1000);
     EXPECT_EQUAL(bp->estimate(), expect);
diff --git a/searchlib/src/tests/queryeval/flow/queryeval_flow_test.cpp b/searchlib/src/tests/queryeval/flow/queryeval_flow_test.cpp
index c92f85357b5..9a9adeac2bc 100644
--- a/searchlib/src/tests/queryeval/flow/queryeval_flow_test.cpp
+++ b/searchlib/src/tests/queryeval/flow/queryeval_flow_test.cpp
@@ -156,7 +156,7 @@ TEST(FlowTest, basic_and_flow) {
     for (double in: {1.0, 0.5, 0.25}) {
         for (bool strict: {false, true}) {
             verify_flow(AndFlow(in, strict), {0.4, 0.7, 0.2},
-                        {{in, in, strict},
+                        {{in, 0.0, strict},
                          {in*0.4, in*0.4, false},
                          {in*0.4*0.7, in*0.4*0.7, false},
                          {in*0.4*0.7*0.2, in*0.4*0.7*0.2, false}});
@@ -168,7 +168,7 @@ TEST(FlowTest, basic_or_flow) {
     for (double in: {1.0, 0.5, 0.25}) {
         for (bool strict: {false, true}) {
             verify_flow(OrFlow(in, strict), {0.4, 0.7, 0.2},
-                        {{in, 1.0-in, strict},
+                        {{in, 0.0, strict},
                          {in*0.6, 1.0-in*0.6, strict},
                          {in*0.6*0.3, 1.0-in*0.6*0.3, strict},
                          {in*0.6*0.3*0.8, 1.0-in*0.6*0.3*0.8, strict}});
@@ -180,7 +180,7 @@ TEST(FlowTest, basic_and_not_flow) {
     for (double in: {1.0, 0.5, 0.25}) {
         for (bool strict: {false, true}) {
             verify_flow(AndNotFlow(in, strict), {0.4, 0.7, 0.2},
-                        {{in, in, strict},
+                        {{in, 0.0, strict},
                          {in*0.4, in*0.4, false},
                          {in*0.4*0.3, in*0.4*0.3, false},
                          {in*0.4*0.3*0.8, in*0.4*0.3*0.8, false}});
diff --git a/searchlib/src/vespa/searchlib/queryeval/flow.h b/searchlib/src/vespa/searchlib/queryeval/flow.h
index d711cd74221..86ce6f8b93b 100644
--- a/searchlib/src/vespa/searchlib/queryeval/flow.h
+++ b/searchlib/src/vespa/searchlib/queryeval/flow.h
@@ -177,7 +177,7 @@ public:
         return _strict && _first;
     }
     double estimate() const noexcept {
-        return _flow;
+        return _first ? 0.0 : _flow;
     }
     static void sort(auto adapter, auto &children, bool strict) {
         flow::sort<flow::MinAndCost>(adapter, children);
@@ -200,11 +200,13 @@ class OrFlow : public FlowMixin<OrFlow>{
 private:
     double _flow;
     bool _strict;
+    bool _first;
 public:
     OrFlow(double in, bool strict) noexcept
-      : _flow(in), _strict(strict) {}
+      : _flow(in), _strict(strict), _first(true) {}
     void add(double est) noexcept {
         _flow *= (1.0 - est);
+        _first = false;
     }
     double flow() const noexcept {
         return _flow;
@@ -213,7 +215,7 @@ public:
         return _strict;
     }
     double estimate() const noexcept {
-        return (1.0 - _flow);
+        return _first ? 0.0 : (1.0 - _flow);
     }
     static void sort(auto adapter, auto &children, bool strict) {
         if (strict) {
@@ -247,7 +249,7 @@ public:
         return _strict && _first;
     }
     double estimate() const noexcept {
-        return _flow;
+        return _first ? 0.0 : _flow;
     }
     static void sort(auto adapter, auto &children, bool) {
         flow::sort_partial<flow::MinOrCost>(adapter, children, 1);