LSP: Adds configuration option to enable trace logging to a local file.

Changelog.md

@@ -19,6 +19,7 @@ Compiler Features:
  * Code Generator: More efficient overflow checks for multiplication.
  * Language Server: Analyze all files in a project by default (can be customized by setting ``'file-load-strategy'`` to ``'directly-opened-and-on-import'`` in LSP settings object).
  * Yul Optimizer: Simplify the starting offset of zero-length operations to zero.
+ * Language Server: Adds configuration option ``trace-log-file`` to enable trace logging to a local file.
 
 
 Bugfixes:

libsolidity/lsp/LanguageServer.cpp

@@ -186,6 +186,16 @@ void LanguageServer::changeConfiguration(Json::Value const& _settings)
 			lspAssert(false, ErrorCode::InvalidParams, "Invalid file load strategy: " + text);
 	}
 
+	if (auto traceLogFileNode = _settings["trace-log-file"])
+	{
+		if (traceLogFileNode.isString())
+			m_client.setTraceLogFile(boost::filesystem::path(_settings["trace-log-file"].asString()));
+		if (traceLogFileNode.isNull())
+			m_client.setTraceLogFile(nullopt);
+		else
+			lspAssert(false, ErrorCode::InvalidParams, "Invalid trace-log-file value. Must be a path to a file.");
+	}
+
 	m_settingsObject = _settings;
 	Json::Value jsonIncludePaths = _settings["include-paths"];
 

libsolidity/lsp/Transport.cpp

@@ -27,6 +27,7 @@
 
 #include <boost/algorithm/string.hpp>
 
+#include <fstream>
 #include <iostream>
 #include <sstream>
 #include <string>
@@ -58,6 +59,12 @@ optional<Json::Value> Transport::receive()
 
 	string const data = readBytes(stoul(headers->at("content-length")));
 
+	if (m_traceLogFilePath)
+	{
+		ofstream traceLogger(m_traceLogFilePath.value().generic_string(), ios::app);
+		traceLogger << "Received: " << data << endl;
+	}
+
 	Json::Value jsonMessage;
 	string jsonParsingErrors;
 	solidity::util::jsonParseStrict(data, jsonMessage, &jsonParsingErrors);
@@ -70,7 +77,7 @@ optional<Json::Value> Transport::receive()
 	return {std::move(jsonMessage)};
 }
 
-void Transport::trace(std::string _message, Json::Value _extra)
+void Transport::trace(string _message, Json::Value _extra)
 {
 	if (m_logTrace != TraceValue::Off)
 	{
@@ -82,6 +89,11 @@ void Transport::trace(std::string _message, Json::Value _extra)
 	}
 }
 
+void Transport::setTraceLogFile(std::optional<boost::filesystem::path> _pathToLogFile)
+{
+	m_traceLogFilePath = std::move(_pathToLogFile);
+}
+
 optional<map<string, string>> Transport::parseHeaders()
 {
 	map<string, string> headers;
@@ -137,6 +149,12 @@ void Transport::send(Json::Value _json, MessageID _id)
 	// Trailing CRLF only for easier readability.
 	string const jsonString = solidity::util::jsonCompactPrint(_json);
 
+	if (m_traceLogFilePath)
+	{
+		ofstream traceLogger(m_traceLogFilePath.value().generic_string(), ios::app);
+		traceLogger << "Sending: " << jsonString << endl;
+	}
+
 	writeBytes(fmt::format("Content-Length: {}\r\n\r\n", jsonString.size()));
 	writeBytes(jsonString);
 	flushOutput();

libsolidity/lsp/Transport.h

@@ -21,6 +21,8 @@
 
 #include <json/value.h>
 
+#include <boost/filesystem/path.hpp>
+
 #include <functional>
 #include <iosfwd>
 #include <map>
@@ -103,8 +105,13 @@ public:
 	TraceValue traceValue() const noexcept { return m_logTrace; }
 	void setTrace(TraceValue _value) noexcept { m_logTrace = _value; }
 
+	/// Sets path to a local log file (in addition to reporting the trace log to the client)
+	/// to be written to if trace value is set to verbose.
+	void setTraceLogFile(std::optional<boost::filesystem::path> _pathToLogfile);
+
 private:
 	TraceValue m_logTrace = TraceValue::Off;
+	std::optional<boost::filesystem::path> m_traceLogFilePath;
 
 protected:
 	/// Reads from the transport and parses the headers until the beginning

test/lsp.py

@@ -948,6 +948,11 @@ class SolidityLSPTestSuite: # {{{
                 params['initializationOptions'] = {}
             params['initializationOptions']['include-paths'] = custom_include_paths
 
+        if self.trace_io:
+            if params['initializationOptions'] is None:
+                params['initializationOptions'] = {}
+            params['initializationOptions']['trace-log-file'] = "solc.log"
+
         if not expose_project_root:
             params['rootUri'] = None