Merge pull request #3532 from aarlt/libdevcore_new_json_api

Add new JSON API for better abstraction and for supporting strict JSON parsing

Changelog.md

@@ -2,9 +2,9 @@
 
 Features:
  * Code Generator: Assert that ``k != 0`` for ``molmod(a, b, k)`` and ``addmod(a, b, k)`` as experimental 0.5.0 feature.
+ * Standard JSON: Reject badly formatted invalid JSON inputs.
  * Type Checker: Disallow uninitialized storage pointers as experimental 0.5.0 feature.
 
-
 Bugfixes:
  * JSON-AST: Add "documentation" property to function, event and modifier definition.
  * Resolver: Properly determine shadowing for imports with aliases.

libdevcore/CMakeLists.txt

@@ -2,7 +2,9 @@ file(GLOB sources "*.cpp")
 file(GLOB headers "*.h")
 
 add_library(devcore ${sources} ${headers})
-target_link_libraries(devcore PRIVATE ${Boost_FILESYSTEM_LIBRARIES} ${Boost_REGEX_LIBRARIES} ${Boost_SYSTEM_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
+target_link_libraries(devcore PRIVATE ${JSONCPP_LIBRARY} ${Boost_FILESYSTEM_LIBRARIES} ${Boost_REGEX_LIBRARIES} ${Boost_SYSTEM_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT})
 target_include_directories(devcore SYSTEM PUBLIC ${Boost_INCLUDE_DIRS})
 target_include_directories(devcore PUBLIC "${CMAKE_SOURCE_DIR}")
+target_include_directories(devcore PUBLIC "${JSONCPP_INCLUDE_DIR}")
+add_dependencies(devcore jsoncpp)
 add_dependencies(devcore solidity_BuildInfo.h)

libdevcore/JSON.cpp

@@ -0,0 +1,109 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/** @file JSON.cpp
+ * @author Alexander Arlt <alexander.arlt@arlt-labs.com>
+ * @date 2018
+ */
+
+#include "JSON.h"
+
+#include <sstream>
+#include <map>
+#include <memory>
+
+using namespace std;
+
+namespace dev
+{
+
+namespace
+{
+
+/// StreamWriterBuilder that can be constructed with specific settings
+class StreamWriterBuilder: public Json::StreamWriterBuilder
+{
+public:
+	explicit StreamWriterBuilder(map<string, string> const& _settings)
+	{
+		for (auto const& iter :_settings)
+			this->settings_[iter.first] = iter.second;
+	}
+};
+
+/// CharReaderBuilder with strict-mode settings
+class StrictModeCharReaderBuilder: public Json::CharReaderBuilder
+{
+public:
+	StrictModeCharReaderBuilder()
+	{
+		Json::CharReaderBuilder::strictMode(&this->settings_);
+	}
+};
+
+/// Serialise the JSON object (@a _input) with specific builder (@a _builder)
+/// \param _input JSON input string
+/// \param _builder StreamWriterBuilder that is used to create new Json::StreamWriter
+/// \return serialized json object
+string print(Json::Value const& _input, Json::StreamWriterBuilder const& _builder)
+{
+	stringstream stream;
+	unique_ptr<Json::StreamWriter> writer(_builder.newStreamWriter());
+	writer->write(_input, &stream);
+	return stream.str();
+}
+
+/// Parse a JSON string (@a _input) with specified builder (@ _builder) and writes resulting JSON object to (@a _json)
+/// \param _builder CharReaderBuilder that is used to create new Json::CharReaders
+/// \param _input JSON input string
+/// \param _json [out] resulting JSON object
+/// \param _errs [out] Formatted error messages
+/// \return \c true if the document was successfully parsed, \c false if an error occurred.
+bool parse(Json::CharReaderBuilder& _builder, string const& _input, Json::Value& _json, string* _errs)
+{
+	unique_ptr<Json::CharReader> reader(_builder.newCharReader());
+	return reader->parse(_input.c_str(), _input.c_str() + _input.length(), &_json, _errs);
+}
+
+} // end anonymous namespace
+
+string jsonPrettyPrint(Json::Value const& _input)
+{
+	static map<string, string> settings{{"indentation", "  "}};
+	static StreamWriterBuilder writerBuilder(settings);
+	return print(_input, writerBuilder);
+}
+
+string jsonCompactPrint(Json::Value const& _input)
+{
+	static map<string, string> settings{{"indentation", ""}};
+	static StreamWriterBuilder writerBuilder(settings);
+	return print(_input, writerBuilder);
+}
+
+bool jsonParseStrict(string const& _input, Json::Value& _json, string* _errs /* = nullptr */)
+{
+	static StrictModeCharReaderBuilder readerBuilder;
+	return parse(readerBuilder, _input, _json, _errs);
+}
+
+bool jsonParse(string const& _input, Json::Value& _json, string *_errs /* = nullptr */)
+{
+	static Json::CharReaderBuilder readerBuilder;
+	return parse(readerBuilder, _input, _json, _errs);
+}
+
+} // namespace dev

libdevcore/JSON.h

@@ -24,21 +24,28 @@
 
 #include <json/json.h>
 
-namespace dev
+#include <string>
-{
+
+namespace dev {
 
 /// Serialise the JSON object (@a _input) with indentation
-inline std::string jsonPrettyPrint(Json::Value const& _input)
+std::string jsonPrettyPrint(Json::Value const& _input);
-{
-	return Json::StyledWriter().write(_input);
-}
 
 /// Serialise the JSON object (@a _input) without indentation
-inline std::string jsonCompactPrint(Json::Value const& _input)
+std::string jsonCompactPrint(Json::Value const& _input);
-{
+
-	Json::FastWriter writer;
+/// Parse a JSON string (@a _input) with enabled strict-mode and writes resulting JSON object to (@a _json)
-	writer.omitEndingLineFeed();
+/// \param _input JSON input string
-	return writer.write(_input);
+/// \param _json [out] resulting JSON object
-}
+/// \param _errs [out] Formatted error messages
+/// \return \c true if the document was successfully parsed, \c false if an error occurred.
+bool jsonParseStrict(std::string const& _input, Json::Value& _json, std::string* _errs = nullptr);
+
+/// Parse a JSON string (@a _input) and writes resulting JSON object to (@a _json)
+/// \param _input JSON input string
+/// \param _json [out] resulting JSON object
+/// \param _errs [out] Formatted error messages
+/// \return \c true if the document was successfully parsed, \c false if an error occurred.
+bool jsonParse(std::string const& _input, Json::Value& _json, std::string* _errs = nullptr);
 
 }

libsolc/libsolc.cpp

@@ -203,7 +203,7 @@ string compile(StringMap const& _sources, bool _optimize, CStyleReadFileCallback
 			{
 				Json::Value contractInput = ret["contracts"][sourceName][contractName];
 				Json::Value contractOutput = Json::objectValue;
-				contractOutput["interface"] = dev::jsonCompactPrint(contractInput["abi"]);
+				contractOutput["interface"] = jsonCompactPrint(contractInput["abi"]);
 				contractOutput["metadata"] = contractInput["metadata"];
 				contractOutput["functionHashes"] = contractInput["evm"]["methodIdentifiers"];
 				contractOutput["gasEstimates"] = translateGasEstimates(contractInput["evm"]["gasEstimates"]);
@@ -219,7 +219,7 @@ string compile(StringMap const& _sources, bool _optimize, CStyleReadFileCallback
 
 	try
 	{
-		return dev::jsonCompactPrint(output);
+		return jsonCompactPrint(output);
 	}
 	catch (...)
 	{
@@ -229,15 +229,15 @@ string compile(StringMap const& _sources, bool _optimize, CStyleReadFileCallback
 
 string compileMulti(string const& _input, bool _optimize, CStyleReadFileCallback _readCallback = nullptr)
 {
-	Json::Reader reader;
+	string errors;
 	Json::Value input;
-	if (!reader.parse(_input, input, false))
+	if (!jsonParseStrict(_input, input, &errors))
 	{
-		Json::Value errors(Json::arrayValue);
+		Json::Value jsonErrors(Json::arrayValue);
-		errors.append("Error parsing input JSON: " + reader.getFormattedErrorMessages());
+		jsonErrors.append("Error parsing input JSON: " + errors);
 		Json::Value output(Json::objectValue);
-		output["errors"] = errors;
+		output["errors"] = jsonErrors;
-		return dev::jsonCompactPrint(output);
+		return jsonCompactPrint(output);
 	}
 	else
 	{

libsolidity/interface/StandardCompiler.cpp

@@ -554,12 +554,11 @@ Json::Value StandardCompiler::compile(Json::Value const& _input)
 string StandardCompiler::compile(string const& _input)
 {
 	Json::Value input;
-	Json::Reader reader;
+	string errors;
-
 	try
 	{
-		if (!reader.parse(_input, input, false))
+		if (!jsonParseStrict(_input, input, &errors))
-			return jsonCompactPrint(formatFatalError("JSONError", reader.getFormattedErrorMessages()));
+			return jsonCompactPrint(formatFatalError("JSONError", errors));
 	}
 	catch(...)
 	{

test/Metadata.cpp

@@ -50,7 +50,7 @@ string bytecodeSansMetadata(string const& _bytecode)
 bool isValidMetadata(string const& _metadata)
 {
 	Json::Value metadata;
-	if (!Json::Reader().parse(_metadata, metadata, false))
+	if (!jsonParseStrict(_metadata, metadata))
 		return false;
 
 	if (

test/RPCSession.cpp

@@ -23,8 +23,7 @@
 
 #include <libdevcore/CommonData.h>
 
-#include <json/reader.h>
+#include <libdevcore/JSON.h>
-#include <json/writer.h>
 
 #include <string>
 #include <stdio.h>
@@ -216,7 +215,7 @@ string RPCSession::personal_newAccount(string const& _password)
 
 void RPCSession::test_setChainParams(vector<string> const& _accounts)
 {
-	static std::string const c_configString = R"(
+	static string const c_configString = R"(
 	{
 		"sealEngine": "NoProof",
 		"params": {
@@ -249,10 +248,10 @@ void RPCSession::test_setChainParams(vector<string> const& _accounts)
 	)";
 
 	Json::Value config;
-	BOOST_REQUIRE(Json::Reader().parse(c_configString, config));
+	BOOST_REQUIRE(jsonParseStrict(c_configString, config));
 	for (auto const& account: _accounts)
 		config["accounts"][account]["wei"] = "0x100000000000000000000000000000000000000000";
-	test_setChainParams(Json::FastWriter().write(config));
+	test_setChainParams(jsonCompactPrint(config));
 }
 
 void RPCSession::test_setChainParams(string const& _config)
@@ -328,7 +327,7 @@ Json::Value RPCSession::rpcCall(string const& _methodName, vector<string> const&
 	BOOST_TEST_MESSAGE("Reply: " + reply);
 
 	Json::Value result;
-	BOOST_REQUIRE(Json::Reader().parse(reply, result, false));
+	BOOST_REQUIRE(jsonParseStrict(reply, result));
 
 	if (result.isMember("error"))
 	{
@@ -371,6 +370,5 @@ string RPCSession::TransactionData::toJson() const
 	json["gasprice"] = gasPrice;
 	json["value"] = value;
 	json["data"] = data;
-	return Json::FastWriter().write(json);
+	return jsonCompactPrint(json);
-
 }

test/fuzzer.cpp

@@ -22,7 +22,7 @@
 #include <libevmasm/ConstantOptimiser.h>
 #include <libsolc/libsolc.h>
 
-#include <json/json.h>
+#include <libdevcore/JSON.h>
 
 #include <boost/program_options.hpp>
 
@@ -101,7 +101,7 @@ void testStandardCompiler()
 	string input = readInput();
 	string outputString(compileStandard(input.c_str(), NULL));
 	Json::Value output;
-	if (!Json::Reader().parse(outputString, output))
+	if (!jsonParseStrict(outputString, output))
 	{
 		cout << "Compiler produced invalid JSON output." << endl;
 		abort();
@@ -129,7 +129,7 @@ void testCompiler(bool optimize)
 
 	string outputString(compileJSON(input.c_str(), optimize));
 	Json::Value outputJson;
-	if (!Json::Reader().parse(outputString, outputJson))
+	if (!jsonParseStrict(outputString, outputJson))
 	{
 		cout << "Compiler produced invalid JSON output." << endl;
 		abort();

test/libdevcore/JSON.cpp

@@ -0,0 +1,151 @@
+/*
+	This file is part of solidity.
+
+	solidity is free software: you can redistribute it and/or modify
+	it under the terms of the GNU General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	solidity is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with solidity.  If not, see <http://www.gnu.org/licenses/>.
+*/
+/**
+ * @date 2018
+ * Unit tests for JSON.h.
+ */
+
+#include <libdevcore/JSON.h>
+
+#include "../TestHelper.h"
+
+using namespace std;
+
+namespace dev
+{
+namespace test
+{
+
+BOOST_AUTO_TEST_SUITE(JsonTest)
+
+BOOST_AUTO_TEST_CASE(json_pretty_print)
+{
+	Json::Value json;
+	Json::Value jsonChild;
+
+	jsonChild["3.1"] = "3.1";
+	jsonChild["3.2"] = 2;
+	json["1"] = 1;
+	json["2"] = "2";
+	json["3"] = jsonChild;
+
+	BOOST_CHECK(
+	"{\n"
+	"  \"1\" : 1,\n"
+	"  \"2\" : \"2\",\n"
+	"  \"3\" : \n"
+	"  {\n"
+	"    \"3.1\" : \"3.1\",\n"
+	"    \"3.2\" : 2\n"
+	"  }\n"
+	"}" == jsonPrettyPrint(json));
+}
+
+BOOST_AUTO_TEST_CASE(json_compact_print)
+{
+	Json::Value json;
+	Json::Value jsonChild;
+
+	jsonChild["3.1"] = "3.1";
+	jsonChild["3.2"] = 2;
+	json["1"] = 1;
+	json["2"] = "2";
+	json["3"] = jsonChild;
+
+	BOOST_CHECK("{\"1\":1,\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":2}}" == jsonCompactPrint(json));
+}
+
+BOOST_AUTO_TEST_CASE(parse_json_not_strict)
+{
+	Json::Value json;
+	std::string errors;
+
+	// just parse a valid json input
+	BOOST_CHECK(jsonParse("{\"1\":1,\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":2}}", json, &errors));
+	BOOST_CHECK(json["1"] == 1);
+	BOOST_CHECK(json["2"] == "2");
+	BOOST_CHECK(json["3"]["3.1"] == "3.1");
+	BOOST_CHECK(json["3"]["3.2"] == 2);
+
+	// trailing garbage is allowed here
+	BOOST_CHECK(jsonParse("{\"1\":2,\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":3}}}}}}}}}}", json, &errors));
+	BOOST_CHECK(json["1"] == 2);
+	BOOST_CHECK(json["2"] == "2");
+	BOOST_CHECK(json["3"]["3.1"] == "3.1");
+	BOOST_CHECK(json["3"]["3.2"] == 3);
+
+	// comments are allowed
+	BOOST_CHECK(jsonParse(
+		"{\"1\":3, // awesome comment\n\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":4}}", json, &errors
+	));
+	BOOST_CHECK(json["1"] == 3);
+	BOOST_CHECK(json["2"] == "2");
+	BOOST_CHECK(json["3"]["3.1"] == "3.1");
+	BOOST_CHECK(json["3"]["3.2"] == 4);
+
+	// root element other than object or array is allowed
+	BOOST_CHECK(jsonParse("[]", json, &errors));
+	BOOST_CHECK(jsonParse("{}", json, &errors));
+	BOOST_CHECK(jsonParse("1", json, &errors));
+	BOOST_CHECK(json == 1);
+	BOOST_CHECK(jsonParse("\"hello\"", json, &errors));
+	BOOST_CHECK(json == "hello");
+
+	// non-UTF-8 escapes allowed
+	BOOST_CHECK(jsonParse("[ \"\x80\xec\x80\" ]", json, &errors));
+	BOOST_CHECK(json[0] == "\x80\xec\x80");
+}
+
+BOOST_AUTO_TEST_CASE(parse_json_strict)
+{
+	Json::Value json;
+	std::string errors;
+
+	// just parse a valid json input
+	BOOST_CHECK(jsonParseStrict("{\"1\":1,\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":2}}", json, &errors));
+	BOOST_CHECK(json["1"] == 1);
+	BOOST_CHECK(json["2"] == "2");
+	BOOST_CHECK(json["3"]["3.1"] == "3.1");
+	BOOST_CHECK(json["3"]["3.2"] == 2);
+
+	// trailing garbage is not allowed in strict-mode
+	BOOST_CHECK(!jsonParseStrict("{\"1\":2,\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":3}}}}}}}}}}", json, &errors));
+
+	// comments are allowed in strict-mode? - that's strange...
+	BOOST_CHECK(jsonParseStrict(
+		"{\"1\":3, // awesome comment\n\"2\":\"2\",\"3\":{\"3.1\":\"3.1\",\"3.2\":5}}", json, &errors
+	));
+	BOOST_CHECK(json["1"] == 3);
+	BOOST_CHECK(json["2"] == "2");
+	BOOST_CHECK(json["3"]["3.1"] == "3.1");
+	BOOST_CHECK(json["3"]["3.2"] == 5);
+
+	// root element can only be object or array
+	BOOST_CHECK(jsonParseStrict("[]", json, &errors));
+	BOOST_CHECK(jsonParseStrict("{}", json, &errors));
+	BOOST_CHECK(!jsonParseStrict("1", json, &errors));
+	BOOST_CHECK(!jsonParseStrict("\"hello\"", json, &errors));
+
+	// non-UTF-8 escapes allowed??
+	BOOST_CHECK(jsonParseStrict("[ \"\x80\xec\x80\" ]", json, &errors));
+	BOOST_CHECK(json[0] == "\x80\xec\x80");
+}
+
+BOOST_AUTO_TEST_SUITE_END()
+
+}
+}

test/libsolidity/JSONCompiler.cpp

@@ -44,7 +44,7 @@ Json::Value compileSingle(string const& _input)
 {
 	string output(compileJSON(_input.c_str(), dev::test::Options::get().optimize));
 	Json::Value ret;
-	BOOST_REQUIRE(Json::Reader().parse(output, ret, false));
+	BOOST_REQUIRE(jsonParseStrict(output, ret));
 	return ret;
 }
 
@@ -56,7 +56,7 @@ Json::Value compileMulti(string const& _input, bool _callback)
 		compileJSONMulti(_input.c_str(), dev::test::Options::get().optimize)
 	);
 	Json::Value ret;
-	BOOST_REQUIRE(Json::Reader().parse(output, ret, false));
+	BOOST_REQUIRE(jsonParseStrict(output, ret));
 	return ret;
 }
 
@@ -64,7 +64,7 @@ Json::Value compile(string const& _input)
 {
 	string output(compileStandard(_input.c_str(), NULL));
 	Json::Value ret;
-	BOOST_REQUIRE(Json::Reader().parse(output, ret, false));
+	BOOST_REQUIRE(jsonParseStrict(output, ret));
 	return ret;
 }
 

test/libsolidity/Metadata.cpp

@@ -23,6 +23,7 @@
 #include "../TestHelper.h"
 #include <libsolidity/interface/CompilerStack.h>
 #include <libdevcore/SwarmHash.h>
+#include <libdevcore/JSON.h>
 
 namespace dev
 {
@@ -111,7 +112,7 @@ BOOST_AUTO_TEST_CASE(metadata_relevant_sources)
 	std::string const& serialisedMetadata = compilerStack.metadata("A");
 	BOOST_CHECK(dev::test::isValidMetadata(serialisedMetadata));
 	Json::Value metadata;
-	BOOST_REQUIRE(Json::Reader().parse(serialisedMetadata, metadata, false));
+	BOOST_REQUIRE(jsonParseStrict(serialisedMetadata, metadata));
 
 	BOOST_CHECK_EQUAL(metadata["sources"].size(), 1);
 	BOOST_CHECK(metadata["sources"].isMember("A"));
@@ -149,7 +150,7 @@ BOOST_AUTO_TEST_CASE(metadata_relevant_sources_imports)
 	std::string const& serialisedMetadata = compilerStack.metadata("C");
 	BOOST_CHECK(dev::test::isValidMetadata(serialisedMetadata));
 	Json::Value metadata;
-	BOOST_REQUIRE(Json::Reader().parse(serialisedMetadata, metadata, false));
+	BOOST_REQUIRE(jsonParseStrict(serialisedMetadata, metadata));
 
 	BOOST_CHECK_EQUAL(metadata["sources"].size(), 3);
 	BOOST_CHECK(metadata["sources"].isMember("A"));

test/libsolidity/SolidityABIJSON.cpp

@@ -26,7 +26,7 @@
 #include <libdevcore/Exceptions.h>
 #include <libdevcore/SwarmHash.h>
 
-#include <json/json.h>
+#include <libdevcore/JSON.h>
 
 namespace dev
 {
@@ -48,7 +48,7 @@ public:
 
 		Json::Value generatedInterface = m_compilerStack.contractABI(m_compilerStack.lastContractName());
 		Json::Value expectedInterface;
-		BOOST_REQUIRE(m_reader.parse(_expectedInterfaceString, expectedInterface));
+		BOOST_REQUIRE(jsonParseStrict(_expectedInterfaceString, expectedInterface));
 		BOOST_CHECK_MESSAGE(
 			expectedInterface == generatedInterface,
 			"Expected:\n" << expectedInterface.toStyledString() <<
@@ -58,7 +58,6 @@ public:
 
 protected:
 	CompilerStack m_compilerStack;
-	Json::Reader m_reader;
 };
 
 BOOST_FIXTURE_TEST_SUITE(SolidityABIJSON, JSONInterfaceChecker)

test/libsolidity/SolidityNatspecJSON.cpp

@@ -22,7 +22,7 @@
 
 #include "../TestHelper.h"
 #include <string>
-#include <json/json.h>
+#include <libdevcore/JSON.h>
 #include <libsolidity/interface/CompilerStack.h>
 #include <libsolidity/interface/Exceptions.h>
 #include <libdevcore/Exceptions.h>
@@ -55,7 +55,7 @@ public:
 		else
 			generatedDocumentation = m_compilerStack.natspecDev(m_compilerStack.lastContractName());
 		Json::Value expectedDocumentation;
-		m_reader.parse(_expectedDocumentationString, expectedDocumentation);
+		jsonParseStrict(_expectedDocumentationString, expectedDocumentation);
 		BOOST_CHECK_MESSAGE(
 			expectedDocumentation == generatedDocumentation,
 			"Expected:\n" << expectedDocumentation.toStyledString() <<
@@ -73,7 +73,6 @@ public:
 
 private:
 	CompilerStack m_compilerStack;
-	Json::Reader m_reader;
 };
 
 BOOST_FIXTURE_TEST_SUITE(SolidityNatspecJSON, DocumentationChecker)

test/libsolidity/StandardCompiler.cpp

@@ -89,7 +89,7 @@ Json::Value compile(string const& _input)
 	StandardCompiler compiler;
 	string output = compiler.compile(_input);
 	Json::Value ret;
-	BOOST_REQUIRE(Json::Reader().parse(output, ret, false));
+	BOOST_REQUIRE(jsonParseStrict(output, ret));
 	return ret;
 }
 
@@ -110,11 +110,11 @@ BOOST_AUTO_TEST_CASE(assume_object_input)
 
 	/// Use the string interface of StandardCompiler to trigger these
 	result = compile("");
-	BOOST_CHECK(containsError(result, "JSONError", "* Line 1, Column 1\n  Syntax error: value, object or array expected.\n"));
+	BOOST_CHECK(containsError(result, "JSONError", "* Line 1, Column 1\n  Syntax error: value, object or array expected.\n* Line 1, Column 1\n  A valid JSON document must be either an array or an object value.\n"));
 	result = compile("invalid");
-	BOOST_CHECK(containsError(result, "JSONError", "* Line 1, Column 1\n  Syntax error: value, object or array expected.\n"));
+	BOOST_CHECK(containsError(result, "JSONError", "* Line 1, Column 1\n  Syntax error: value, object or array expected.\n* Line 1, Column 2\n  Extra non-whitespace after JSON value.\n"));
 	result = compile("\"invalid\"");
-	BOOST_CHECK(containsError(result, "JSONError", "Input is not a JSON object."));
+	BOOST_CHECK(containsError(result, "JSONError", "* Line 1, Column 1\n  A valid JSON document must be either an array or an object value.\n"));
 	BOOST_CHECK(!containsError(result, "JSONError", "* Line 1, Column 1\n  Syntax error: value, object or array expected.\n"));
 	result = compile("{}");
 	BOOST_CHECK(!containsError(result, "JSONError", "* Line 1, Column 1\n  Syntax error: value, object or array expected.\n"));
@@ -190,6 +190,25 @@ BOOST_AUTO_TEST_CASE(sources_is_array)
 	BOOST_CHECK(containsError(result, "JSONError", "\"sources\" is not a JSON object."));
 }
 
+BOOST_AUTO_TEST_CASE(unexpected_trailing_test)
+{
+	char const* input = R"(
+	{
+		"language": "Solidity",
+		"sources": {
+			"A": {
+				"content": "contract A { function f() {} }"
+			}
+		}
+	}
+	}
+	}
+	)";
+	Json::Value result = compile(input);
+	BOOST_CHECK(containsError(result, "JSONError", "* Line 10, Column 2\n  Extra non-whitespace after JSON value.\n"));
+}
+
+
 BOOST_AUTO_TEST_CASE(smoke_test)
 {
 	char const* input = R"(