Fix deadlock in service requests when running local callbacks (backport #671)

[mergify]

🦟 Bug fix

Summary

There scope of the mutex lock is unnecessarily large which causes deadlocks in service requests when running local callbacks. This PR uses the same approach as the Node::Request shown below to reduce the scope of the mutex:

gz-transport/include/gz/transport/detail/Node.hh

Lines 427 to 466 in 68a3fb2

	//////////////////////////////////////////////////
	template<typename RequestT, typename ReplyT>
	bool Node::Request(
	const std::string &_topic,
	const RequestT &_request,
	std::function<void(const ReplyT &_reply, const bool _result)> &_cb)
	{
	// Topic remapping.
	std::string topic = _topic;
	this->Options().TopicRemap(_topic, topic);
	std::string fullyQualifiedTopic;
	if (!TopicUtils::FullyQualifiedName(this->Options().Partition(),
	this->Options().NameSpace(), topic, fullyQualifiedTopic))
	{
	std::cerr << "Service [" << topic << "] is not valid." << std::endl;
	return false;
	}
	bool localResponserFound;
	IRepHandlerPtr repHandler;
	{
	std::lock_guard<std::recursive_mutex> lk(this->Shared()->mutex);
	localResponserFound = this->Shared()->repliers.FirstHandler(
	fullyQualifiedTopic,
	std::string(RequestT().GetTypeName()),
	std::string(ReplyT().GetTypeName()),
	repHandler);
	}
	// If the responser is within my process.
	if (localResponserFound)
	{
	// There is a responser in my process, let's use it.
	ReplyT rep;
	bool result = repHandler->RunLocalCallback(_request, rep);
	_cb(rep, result);
	return true;
	}

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
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This is an automatic backport of pull request #671 done by [Mergify](https://mergify.com).