I'm currently running into a bug where it seems like channels aren't being closed down like they should. This manifests in everything blocking up after many websocket connections. map< and pipe are involved, I think this is the clue I needed :-).
#(async/map< pr-str (async/tap a-mult (async/chan))) The return value from this function was expected to be a channel that the jetty7 core.async websocket integration creates and manages during the lifecycle of a websocket connection. if map< isn't returning a channel, then I guess I can't expect the jetty-7-websockets integration to do the right thing when it tries to close it! On Mon, Apr 7, 2014 at 11:43 AM, Timothy Baldridge <[email protected]>wrote: > But yes, we should probably at least put a note in the docs for map< > stating "returning nil from the mapping function can result in undefined > behavior". Or add an assert somewhere perhaps. > > Timothy > > > On Mon, Apr 7, 2014 at 9:36 AM, James Reeves <[email protected]>wrote: > >> This looks like a bug to me. A lot of the internal core.async functions >> rely on nil values indicating the channel is closed. >> >> - James >> >> >> On 7 April 2014 16:26, Alejandro Ciniglio <[email protected]> wrote: >> >>> Using core.async, I've understood the convention to be that if you take >>> nil from a channel, that channel is closed. This seems to hold for most >>> cases, but I've found a corner case when using map< that lets you pull nil >>> from a channel that is not closed. >>> >>> (def a (chan)) >>> (def c (map< seq a)) >>> (go (prn (<! c))) >>> (>!! a []) >>> ; => nil nil ;; [one nil is printed, one is returned] >>> (go (prn (<! c))) >>> (>!! a [1]) >>> ; => nil (1) >>> >>> This can be chained as well (e.g. (map< identity (map< seq a)) ), and >>> nils just flow through. >>> >>> From looking at the implementation, it's apparent that this happens >>> because the function application of map happens when taking from the output >>> channel so nil is not technically on the channel, (unless it flows through >>> to another map). >>> >>> Is this a bug or is my mental model of nil => closed incorrect? >>> >>> Thanks, >>> Alejandro >>> >>> -- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To post to this group, send email to [email protected] >>> Note that posts from new members are moderated - please be patient with >>> your first post. >>> To unsubscribe from this group, send email to >>> [email protected] >>> For more options, visit this group at >>> http://groups.google.com/group/clojure?hl=en >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "Clojure" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to [email protected] >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/clojure?hl=en >> --- >> You received this message because you are subscribed to the Google Groups >> "Clojure" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > "One of the main causes of the fall of the Roman Empire was that-lacking > zero-they had no way to indicate successful termination of their C > programs." > (Robert Firth) > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to [email protected] > Note that posts from new members are moderated - please be patient with > your first post. > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en > --- > You received this message because you are subscribed to the Google Groups > "Clojure" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to [email protected] Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
