Store error vector and SQL state in DatabaseException

AGENTS.md

@@ -24,3 +24,6 @@
 ### Tests
 - Run the Boost.Test suite with `ctest --preset default --verbose`.
 - Boost.Test options can be used with environments variables like `BOOST_TEST_LOG_LEVEL=all`.
+- Prefer fewer, comprehensive test cases over many small single-assertion tests. A single test case should verify
+  all related properties together (e.g., check the full error vector structure in one test instead of separate tests
+  for each field).

src/fb-cpp/Exception.cpp

@@ -25,6 +25,7 @@
 #include "Exception.h"
 #include "Client.h"
 #include <string>
+#include <vector>
 #include <cassert>
 
 using namespace fbcpp;
@@ -84,3 +85,91 @@ std::string DatabaseException::buildMessage(Client& client, const std::intptr_t*
 
 	return message;
 }
+
+void DatabaseException::copyErrorVector(const std::intptr_t* statusVector)
+{
+	if (!statusVector)
+		return;
+
+	const auto* p = statusVector;
+
+	while (*p != isc_arg_end)
+	{
+		const auto argType = *p++;
+
+		switch (argType)
+		{
+			case isc_arg_gds:
+			case isc_arg_number:
+				errorVector.push_back(argType);
+				errorVector.push_back(*p++);
+				break;
+
+			case isc_arg_string:
+			case isc_arg_interpreted:
+			case isc_arg_sql_state:
+				errorVector.push_back(argType);
+				errorStrings.emplace_back(reinterpret_cast<const char*>(*p++));
+				errorVector.push_back(0);  // placeholder for string pointer
+				break;
+
+			case isc_arg_cstring:
+			{
+				const auto len = static_cast<size_t>(*p++);
+				const auto str = reinterpret_cast<const char*>(*p++);
+				errorVector.push_back(isc_arg_string);
+				errorStrings.emplace_back(str, len);
+				errorVector.push_back(0);  // placeholder for string pointer
+				break;
+			}
+
+			default:
+				errorVector.push_back(argType);
+				errorVector.push_back(*p++);
+				break;
+		}
+	}
+
+	errorVector.push_back(isc_arg_end);
+
+	fixupStringPointers();
+}
+
+void DatabaseException::fixupStringPointers()
+{
+	size_t strIdx = 0;
+	size_t i = 0;
+
+	while (i < errorVector.size() && errorVector[i] != isc_arg_end)
+	{
+		const auto argType = errorVector[i];
+
+		if (argType == isc_arg_string || argType == isc_arg_interpreted || argType == isc_arg_sql_state)
+			errorVector[i + 1] = reinterpret_cast<std::intptr_t>(errorStrings[strIdx++].c_str());
+
+		i += 2;
+	}
+}
+
+std::string DatabaseException::extractSqlState(const std::intptr_t* statusVector)
+{
+	if (!statusVector)
+		return {};
+
+	const auto* p = statusVector;
+
+	while (*p != isc_arg_end)
+	{
+		const auto argType = *p++;
+
+		if (argType == isc_arg_sql_state)
+			return reinterpret_cast<const char*>(*p);
+
+		if (argType == isc_arg_cstring)
+			p += 2;
+		else
+			p++;
+	}
+
+	return {};
+}

src/fb-cpp/Exception.h

@@ -28,6 +28,7 @@
 #include "fb-api.h"
 #include <stdexcept>
 #include <string>
+#include <vector>
 #include <cstdint>
 
 
@@ -199,18 +200,69 @@ namespace fbcpp
 	class DatabaseException final : public FbCppException
 	{
 	public:
-		using FbCppException::FbCppException;
-
 		///
 		/// Constructs a DatabaseException from a Firebird status vector.
 		///
-		explicit DatabaseException(Client& client, const std::intptr_t* status)
-			: FbCppException{buildMessage(client, status)}
+		explicit DatabaseException(Client& client, const std::intptr_t* statusVector)
+			: FbCppException{buildMessage(client, statusVector)},
+			  sqlState{extractSqlState(statusVector)}
+		{
+			copyErrorVector(statusVector);
+		}
+
+		DatabaseException(const DatabaseException& other)
+			: FbCppException{static_cast<const FbCppException&>(other)},
+			  errorVector{other.errorVector},
+			  errorStrings{other.errorStrings},
+			  sqlState{other.sqlState}
+		{
+			fixupStringPointers();
+		}
+
+		DatabaseException(DatabaseException&&) = default;
+
+		DatabaseException& operator=(const DatabaseException&) = delete;
+		DatabaseException& operator=(DatabaseException&&) = delete;
+
+		///
+		/// Returns the Firebird error vector.
+		/// The vector is terminated by isc_arg_end.
+		///
+		const std::vector<std::intptr_t>& getErrors() const noexcept
+		{
+			return errorVector;
+		}
+
+		///
+		/// Returns the primary ISC error code (first isc_arg_gds value), or 0 if none.
+		///
+		std::intptr_t getErrorCode() const noexcept
+		{
+			if (errorVector.size() >= 2 && errorVector[0] == isc_arg_gds)
+				return errorVector[1];
+			return 0;
+		}
+
+		///
+		/// Returns the SQL state string (e.g. "42000") if present in the original status vector,
+		/// or empty otherwise.
+		///
+		const std::string& getSqlState() const noexcept
 		{
+			return sqlState;
 		}
 
 	private:
-		static std::string buildMessage(Client& client, const std::intptr_t* status);
+		static std::string buildMessage(Client& client, const std::intptr_t* statusVector);
+		static std::string extractSqlState(const std::intptr_t* statusVector);
+
+		void copyErrorVector(const std::intptr_t* statusVector);
+		void fixupStringPointers();
+
+	private:
+		std::vector<std::intptr_t> errorVector;
+		std::vector<std::string> errorStrings;
+		std::string sqlState;
 	};
 }  // namespace fbcpp
 

src/test/Exception.cpp

@@ -0,0 +1,70 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2026 F.D.Castel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "TestUtil.h"
+#include "fb-cpp/Exception.h"
+#include "fb-cpp/Statement.h"
+#include "fb-cpp/Transaction.h"
+#include <string>
+
+
+BOOST_AUTO_TEST_SUITE(DatabaseExceptionSuite)
+
+BOOST_AUTO_TEST_CASE(syntaxErrorExceptionProperties)
+{
+	const auto database = getTempFile("Exception-syntaxErrorExceptionProperties.fdb");
+
+	Attachment attachment{CLIENT, database, AttachmentOptions().setCreateDatabase(true)};
+	FbDropDatabase attachmentDrop{attachment};
+
+	Transaction transaction{attachment};
+
+	try
+	{
+		Statement stmt{attachment, transaction, "INVALID SQL STATEMENT !!!"};
+		BOOST_FAIL("Expected DatabaseException was not thrown");
+	}
+	catch (const DatabaseException& ex)
+	{
+		// what() should contain a formatted error message
+		std::string message = ex.what();
+		BOOST_CHECK(!message.empty());
+
+		// Error vector should start with isc_arg_gds and end with isc_arg_end
+		const auto& errors = ex.getErrors();
+		BOOST_REQUIRE(errors.size() >= 2);
+		BOOST_CHECK_EQUAL(errors[0], isc_arg_gds);
+		BOOST_CHECK_EQUAL(errors.back(), isc_arg_end);
+
+		// getErrorCode() should return the first GDS code
+		BOOST_CHECK_NE(ex.getErrorCode(), 0);
+		BOOST_CHECK_EQUAL(ex.getErrorCode(), errors[1]);
+
+		// SQL state, when present, should be a 5-character string
+		if (!ex.getSqlState().empty())
+			BOOST_CHECK_EQUAL(ex.getSqlState().size(), 5u);
+	}
+}
+
+BOOST_AUTO_TEST_SUITE_END()