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fix universal: fix initialization of default values in FindOrDefault #1187

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fix universal: fix initialization of default values in FindOrDefault #1187

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b9622c0
fix universal: fix initialization of default values in FindOrDefault
ddvamp Apr 25, 2026
14f9af8
fix universal: add more tests for FindOrDefault
ddvamp Apr 26, 2026
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6 changes: 4 additions & 2 deletions universal/include/userver/utils/algo.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -57,15 +57,17 @@ auto* FindOrNullptr(Container& container, const Key& key) {
template <typename Container, typename Key, typename Default>
auto FindOrDefault(Container& container, const Key& key, Default&& def) {
const auto* ptr = USERVER_NAMESPACE::utils::FindOrNullptr(container, key);
return (ptr ? *ptr : decltype(*ptr){std::forward<Default>(def)});
using R = std::remove_cvref_t<decltype(*ptr)>;
return (ptr ? *ptr : R(std::forward<Default>(def)));
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@apolukhin apolukhin Apr 23, 2026 •
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please, add tests for the functionality

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@ddvamp ddvamp Apr 25, 2026

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What exactly should they test?

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@apolukhin apolukhin Apr 26, 2026

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Нужно создать тест, который показывает проблему, исправляемую в PR

Те тесты что сейчас добавлены, кажется что проблему не подсвечивают

}

/// @brief Returns default value if no key in associative container, otherwise
/// returns a copy of the stored value.
template <typename Container, typename Key>
auto FindOrDefault(Container& container, const Key& key) {
const auto* ptr = USERVER_NAMESPACE::utils::FindOrNullptr(container, key);
return (ptr ? *ptr : decltype(*ptr){});
using R = std::remove_cvref_t<decltype(*ptr)>;
return (ptr ? *ptr : R());
}

/// @brief Returns std::nullopt if no key in associative container, otherwise
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69 changes: 66 additions & 3 deletions universal/src/utils/algo_test.cpp
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Original file line number Diff line number Diff line change
@@ -1,6 +1,8 @@
#include <userver/utils/algo.hpp>

#include <initializer_list>
#include <map>
#include <set>
#include <string>
#include <string_view>
#include <unordered_map>
Expand Down Expand Up @@ -48,21 +50,26 @@ TEST(UtilsAlgo, FindOrNullptrSets) {

TEST(UtilsAlgo, FindOrDefaultMaps) {
constexpr int kFallback = 42;
constexpr int kDefault = int();
std::map<std::string, int> m = {{"1", 2}};
std::unordered_map<std::string, int> um = {{"1", 2}};

EXPECT_EQ(utils::FindOrDefault(m, "2", kFallback), kFallback);
EXPECT_EQ(utils::FindOrDefault(um, "2", kFallback), kFallback);

ASSERT_EQ(utils::FindOrDefault(m, "1", kFallback), 2);
ASSERT_EQ(utils::FindOrDefault(um, "1", kFallback), 2);

EXPECT_EQ(utils::FindOrDefault(m, "1", kFallback), 2);
EXPECT_EQ(utils::FindOrDefault(um, "1", kFallback), 2);

EXPECT_EQ(utils::FindOrDefault(m, "2"), kDefault);
EXPECT_EQ(utils::FindOrDefault(um, "2"), kDefault);

EXPECT_EQ(utils::FindOrDefault(m, "1"), 2);
EXPECT_EQ(utils::FindOrDefault(um, "1"), 2);
}

TEST(UtilsAlgo, FindOrDefaultSets) {
constexpr int kFallback = 42;
constexpr int kDefault = int();
std::set<int> s = {1};
std::unordered_set<int> us = {1};

Expand All @@ -71,6 +78,62 @@ TEST(UtilsAlgo, FindOrDefaultSets) {

EXPECT_EQ(utils::FindOrDefault(s, 1, kFallback), 1);
EXPECT_EQ(utils::FindOrDefault(us, 1, kFallback), 1);

EXPECT_EQ(utils::FindOrDefault(s, 2), kDefault);
EXPECT_EQ(utils::FindOrDefault(us, 2), kDefault);

EXPECT_EQ(utils::FindOrDefault(s, 1), 1);
EXPECT_EQ(utils::FindOrDefault(us, 1), 1);
}

TEST(UtilsAlgo, FindOrDefaultNoList) {
struct List {
int val = 0;

List() = default;
List(const List&) = default;
explicit List(int v) : val(v) {}
List(std::initializer_list<int>) : val(-1) {}

auto operator<=>(const List&) const = default;
};

constexpr int kFallback = 42;
constexpr int kDefault = List().val;

std::map<int, List> m;
std::set<List> s;

EXPECT_TRUE(m.empty());
EXPECT_EQ(utils::FindOrDefault(m, 0, kFallback).val, kFallback);
EXPECT_EQ(utils::FindOrDefault(m, 0).val, kDefault);

EXPECT_TRUE(s.empty());
EXPECT_EQ(utils::FindOrDefault(s, List(1), kFallback).val, kFallback);
EXPECT_EQ(utils::FindOrDefault(s, List(1)).val, kDefault);
}

TEST(UtilsAlgo, FindOrDefaultNoExtraCopies) {
struct NoCopies {
bool copy = false;

NoCopies() = default;
NoCopies(const NoCopies&) : copy(true) {}
NoCopies(NoCopies&& that) noexcept : copy(that.copy) {}

auto operator<=>(const NoCopies&) const = default;
};

std::map<int, NoCopies> m;
std::set<NoCopies> s;

EXPECT_TRUE(m.empty());
EXPECT_FALSE(utils::FindOrDefault(m, 0, NoCopies()).copy);
EXPECT_FALSE(utils::FindOrDefault(m, 0).copy);

EXPECT_TRUE(s.empty());
EXPECT_FALSE(utils::FindOrDefault(s, NoCopies(), NoCopies()).copy);
EXPECT_FALSE(utils::FindOrDefault(s, NoCopies()).copy);
}

TEST(UtilsAlgo, FindOptionalMaps) {
Expand Down