Serialize enum (#5151)

* Added NLOHNMANN_JSON_SERIALIZE_ENUM_STRICT - duplicate of NLOHMANN_JSON_SERIALIZE_ENUM Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * Added failing tests for NLOHMANN_JSON_SERIALIZE_ENUM_STRICT Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * modified NLOHMANN_JSON_SERIALIZE_STRICT to throw Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * added documentation and changed readme to include NLOHMANN_JSON_SERIALIZE_ENUM_STRICT Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * ran amalgamate Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * docs(macros): add page for JSON_SERIALIZE_ENUM_STRICT - added page to nav - added links to new page where appropriate Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * refactor(macros): make JSON_SERIALIZE_ENUM_STRICT use JSON_THROW - added templated wrapper function to fix scope error in calling JSON_THROW Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * refactor(macros): make NLOHMANN_SERIALIZE_ENUM_STRICT use error code 410 - added error code 410 to docs Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * tests(macros): add test for to_json with enum value not mentioned in mapping for NLOHMANN_JSON_SERIALIZE_ENUM_STRICT Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * Apply suggestions from code review Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com> Signed-off-by: Caillin Nugent <nugentcaillin@gmail.com> * fix(macro): prevent compilation error with -Werror and -Wunused-parameter with NLOHMANN_JSON_SERIALIZE_ENUM_STRICT - casted exception to void to avoid warning Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * fix(docs): add link to NLOHMANN_SERIALIZE_ENUM_STRICT docs to exception page Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * docs(macros): add example of exception throwing for NLOHMANN_JSON_SERIALIZE_ENUM_STRICT Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> * refactor(macros): add more in-depth error message to NLOHMANN_JSON_SERIALIZE_ENUM_STRICT - changed error message to follow style of nlohmann/json#4989 - made description of throw wrapper more general - updated tests and example of exceptions Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> --------- Signed-off-by: Caillin Nugent <caillinn@student.unimelb.edu.au> Signed-off-by: Caillin Nugent <nugentcaillin@gmail.com> Co-authored-by: Niels Lohmann <niels.lohmann@gmail.com>
2026-05-22 06:05:23 +00:00 · 2026-05-19 04:37:07 +10:00
parent 47202c804a
commit 58cfecf7f7
16 changed files with 451 additions and 2 deletions
@@ -1657,6 +1657,84 @@ TEST_CASE("JSON to enum mapping")
    }
 }

+enum class strict_cards {kreuz, pik, herz, karo, andere}; // andere not included in mapping
+
+// NOLINTNEXTLINE(misc-use-internal-linkage,misc-const-correctness,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays) - false positive
+NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(strict_cards,
+{
+    {strict_cards::kreuz, "kreuz"},
+    {strict_cards::pik, "pik"},
+    {strict_cards::pik, "puk"},  // second entry for cards::pik; will not be used
+    {strict_cards::herz, "herz"},
+    {strict_cards::karo, "karo"}
+})
+
+enum StrictTaskState // NOLINT(cert-int09-c,readability-enum-initial-value,cppcoreguidelines-use-enum-class)
+{
+    STRICT_TS_STOPPED,
+    STRICT_TS_RUNNING,
+    STRICT_TS_COMPLETED,
+    STRICT_TS_OTHER, // STRICT_TS_OTHER not in mapping
+    STRICT_TS_INVALID = -1,
+};
+
+// NOLINTNEXTLINE(misc-const-correctness,misc-use-internal-linkage,cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays) - false positive
+NLOHMANN_JSON_SERIALIZE_ENUM_STRICT(StrictTaskState,
+{
+    {STRICT_TS_INVALID, nullptr},
+    {STRICT_TS_STOPPED, "stopped"},
+    {STRICT_TS_RUNNING, "running"},
+    {STRICT_TS_COMPLETED, "completed"},
+})
+
+TEST_CASE("Strict JSON to enum mapping")
+{
+    SECTION("enum class")
+    {
+        // enum -> json
+        CHECK(json(strict_cards::kreuz) == "kreuz");
+        CHECK(json(strict_cards::pik) == "pik");
+        CHECK(json(strict_cards::herz) == "herz");
+        CHECK(json(strict_cards::karo) == "karo");
+
+        // json -> enum
+        CHECK(strict_cards::kreuz == json("kreuz"));
+        CHECK(strict_cards::pik == json("pik"));
+        CHECK(strict_cards::herz == json("herz"));
+        CHECK(strict_cards::karo == json("karo"));
+
+        // invalid json -> exception thrown
+        json _;
+        CHECK_THROWS_WITH_AS(_ = json("what?").get<strict_cards>(), "[json.exception.out_of_range.410] enum value out of range for strict_cards: \"what?\"", json::out_of_range&);
+
+        // conversion of unmapped enum -> exception thrown
+        CHECK_THROWS_WITH_AS(json(strict_cards::andere), "[json.exception.out_of_range.410] enum value out of range for strict_cards", json::out_of_range&);
+    }
+
+    SECTION("traditional enum")
+    {
+        // enum -> json
+        CHECK(json(STRICT_TS_STOPPED) == "stopped");
+        CHECK(json(STRICT_TS_RUNNING) == "running");
+        CHECK(json(STRICT_TS_COMPLETED) == "completed");
+        CHECK(json(STRICT_TS_INVALID) == json());
+
+        // json -> enum
+        CHECK(STRICT_TS_STOPPED == json("stopped"));
+        CHECK(STRICT_TS_RUNNING == json("running"));
+        CHECK(STRICT_TS_COMPLETED == json("completed"));
+        CHECK(STRICT_TS_INVALID == json());
+
+        // invalid json -> exception thrown
+        json _;
+        CHECK_THROWS_WITH_AS(_ = json("what?").get<StrictTaskState>(), "[json.exception.out_of_range.410] enum value out of range for StrictTaskState: \"what?\"", json::out_of_range&);
+
+        // conversion of unmapped enum -> exception thrown
+        CHECK_THROWS_WITH_AS(json(STRICT_TS_OTHER), "[json.exception.out_of_range.410] enum value out of range for StrictTaskState", json::out_of_range&);
+    }
+}
+
+
 #ifdef JSON_HAS_CPP_17
 #if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
 TEST_CASE("std::filesystem::path")