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Niels Lohmann
dd2dd45abd
* Re-amalgamate single_include after #5737 #5737 changed sources under include/ without regenerating single_include, so the single header on develop is out of date. This commit only runs make amalgamate. Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Suppress GCC's false -Warray-bounds error in set_parents() with JSON_DIAGNOSTICS With JSON_DIAGNOSTICS, GCC 13 to 15 report a false -Warray-bounds error at -O3 when set_parents() is inlined right after a non-container value (e.g., a string) was created: the std::map access in the object branch is checked against the string allocation although m_type rules that branch out. GCC 15 fixed the pattern from #4819 but not this one. Suppress -Warray-bounds around set_parents() only, and add a regression test that is compiled with -O3 -Werror=array-bounds on GCC. Fixes #5742 Signed-off-by: Niels Lohmann <mail@nlohmann.me> * Fix the false -Warray-bounds error by setting the type after the value The pragma around set_parents() is no longer needed: the base branch (#5585) creates a value before setting its type. Before, the type of a new string was stored first, so GCC had to assume that operator new could change it again, kept the object branch of the inlined set_parents() alive, and checked it against the string's allocation. Rewriting set_parents() itself (if/else instead of switch) does not help. Verified with Docker GCC 12.5, 13, 14, 15.3 and 16.2: the regression test builds and passes without the pragma, and fails to build on develop. Signed-off-by: Niels Lohmann <mail@nlohmann.me> --------- Signed-off-by: Niels Lohmann <mail@nlohmann.me>
81 lines
2.5 KiB
C++
81 lines
2.5 KiB
C++
// __ _____ _____ _____
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// __| | __| | | | JSON for Modern C++ (supporting code)
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// | | |__ | | | | | | version 3.12.0
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// |_____|_____|_____|_|___| https://github.com/nlohmann/json
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//
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// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
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// SPDX-License-Identifier: MIT
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// Regression test for https://github.com/nlohmann/json/issues/5742: with
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// JSON_DIAGNOSTICS, GCC (12 to at least 16) reported a false -Warray-bounds
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// error in the inlined set_parents() at -O3. The type of a new string was set
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// before the string was allocated, so GCC had to assume that operator new
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// could change it again and checked the object branch of set_parents()
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// against the string's allocation. Setting the type after creating the value
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// avoids this. The warning depends on GCC's inlining decisions, so the
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// sections cover two patterns that trigger it on different GCC versions
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// (#4819 and #5742).
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// On GCC, this file is compiled with -O3 -Werror=array-bounds (see
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// tests/CMakeLists.txt), so the test fails to build if the warning returns.
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#include "doctest_compatibility.h"
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#ifdef JSON_DIAGNOSTICS
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#undef JSON_DIAGNOSTICS
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#endif
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#define JSON_DIAGNOSTICS 1
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#include <nlohmann/json.hpp>
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using nlohmann::json;
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#include <algorithm>
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#include <iterator>
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#include <utility>
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#include <vector>
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namespace
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{
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enum class diag_color
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{
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red,
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green,
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blue
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};
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void to_json(json& j, const diag_color& c)
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{
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static const std::pair<diag_color, json> m[] = // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
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{
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{diag_color::red, "r"},
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{diag_color::green, "g"},
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{diag_color::blue, "b"},
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};
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const auto* it = std::find_if(std::begin(m), std::end(m), [c](const std::pair<diag_color, json>& p)
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{
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return p.first == c;
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});
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j = it->second;
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}
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} // namespace
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TEST_CASE("diagnostics with optimization")
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{
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SECTION("issue #4819 - object in vector")
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{
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std::vector<json> jsons{};
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jsons.emplace_back(json({{"key", "value"}}));
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CHECK(jsons.back()["key"] == "value");
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}
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SECTION("issue #5742 - string values from a static table")
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{
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json j = json::array();
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j.push_back(diag_color::red);
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j.push_back(diag_color::green);
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j.push_back(diag_color::blue);
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CHECK(j.dump() == R"(["r","g","b"])");
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CHECK_THROWS_WITH_AS(j[1].get<int>(), "[json.exception.type_error.302] (/1) type must be number, but is string", json::type_error);
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}
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}
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