"http.CloseNotifier" is deprecated

[im-kulikov]

Deprecate warning

// The CloseNotifier interface is implemented by ResponseWriters which
// allow detecting when the underlying connection has gone away.
//
// This mechanism can be used to cancel long operations on the server
// if the client has disconnected before the response is ready.
//
// Deprecated: the CloseNotifier interface predates Go's context package.
// New code should use Request.Context instead.
type CloseNotifier interface {
	// CloseNotify returns a channel that receives at most a
	// single value (true) when the client connection has gone
	// away.
        // ...
}

[alexaandru]

@vishr @im-kulikov - please correct me if I'm wrong, but while I see this defined in response.go and again in body_dump.go and compress.go in don't see it actually doing anything. Shouldn't they actually read from that channel and abort their respective work in order for this to have done something useful? They clearly don't do that.

Or is the end user supposed to use it in order to abort the work themselves from their handler?

Anyway, looks like we can simply delete it if I read things right (and it doesn't do anything), and update the docs to have the users use c.Request().Context().Done() instead. Sounds like a V4+ feature though...

[im-kulikov]

I can do that for /v4

[alexaandru]

Yes, I think that would work, as long as we introduce it with the very start of v4, that is, in v4.0.0. We cannot introduce it after that, since being a backward incompatible change, we'd need to increment the major number again, and introduce v5.0.0 :-) Thanks!

[im-kulikov]

Let me know as soon as you start forming the v4, I will make these changes

[alexaandru]

Will do!

[vishr]

Sounds good. Please label v4 wherever appropriate.

[alexaandru]

Working on this now. Two things:

1. I cannot create the branch on my fork, since I cannot initialize the module there (if I initialize it with the echo's repo URL, it will error out when testing it, if I initialize it with my fork repo, how can we then later merge it?). So I will create a branch directly on echo repo for this and
2. we can only introduce backward incompatible changes in 4.0.0, so the go module, and the changes for this story need to be on the same branch and same v4.0.0 tag. We cannot introduce them as 4.0.1 but we'd need to use 5.0.0 is we want to have a separate commit for CloseNotifier()

So going to do these both, hope that's ok.

[alexaandru]

Closed via #1269