I am new to phoenix and want to use it with gun to subscribe to websockets. But when I try this in a phoenix project, I get a dependency error. As a minimal example do the following: $ mix phx.new --version Phoenix v1.5.3 $ mix phx.new test --no-ecto [...] Then I add gun to the dependencies: de…

No, that is not possible, Elixir can only load one version of code for a given application. However you may be in luck, it looks like the version of gun on github supports the latest cowlib. You could try doing: {:gun, github: "ninenines/gun"},

This is not a bug. You installed phoenix, which then fetched the latest version of cowlib and locks the version in mix.lock (this happens for all your dependencies). gun however needs an earlier version of cowlib. You’re however unlikely to be using cowlib directly (transitive dependency) and it see…

OK thanks for the explanation. But it now produces a slightly different error for the minimal example from the beginning ot this thread (the 2.6.0 is green and the 2.9.1 red now) $ mix deps.unlock cowlib $ mix deps.get Resolving Hex dependencies... Failed to use "cowlib" (version 2.6.0) because …

Ok, seems like there’s no version of phoenix 1.5, which depends on a cowboy/cowlib low enough to fulfill gun’s requirement. You could try to set the cowlib version in your mix.exs with override: true, but I’m not sure how much cowlib has changed.

Maybe I am wrong but does this mean that gun is outdated and should not depend on old cowlib, i.e. one (=the maintainers of gun) should release a new version of gun to resolve this issue? I will try to override cowlib to a lower version.

Essentially you’re correct. The changes for http → http2 (and upcoming http3) did result in a bunch of updates on the cowboy/cowlib site of things and gun wasn’t updated. There seems to be work for gun 2.0 on github though.

So now I have defp deps do [ {:phoenix, "~> 1.5.3"}, {:phoenix_html, "~> 2.11"}, {:phoenix_live_reload, "~> 1.2", only: :dev}, {:phoenix_live_dashboard, "~> 0.2.0"}, {:telemetry_metrics, "~> 0.4"}, {:telemetry_poller, "~> 0.4"}, {:gettext, "~> 0.11"},…

[image] odohMei7: But can this override cause any problems? Yes. Cowlib could work differently than gun expects, and there can be bugs at runtime. It is quite possible that it isn’t possible to use Phoenix 1.5 and gun 1.3 together at all.

[image] benwilson512: It is quite possible that it isn’t possible to use Phoenix 1.5 and gun 1.3 together at all. Too bad. But is there a way of using two versions of cowlib at the same time, one for gun 1.3 and another for Phoenix 1.5?

I started freash again with the minimal example and put defp deps do [ {:phoenix, "~> 1.5.3"}, {:phoenix_html, "~> 2.11"}, {:phoenix_live_reload, "~> 1.2", only: :dev}, {:phoenix_live_dashboard, "~> 0.2.0"}, {:telemetry_metrics, "~> 0.4"}, {:telemetry_polle…

Ah sorry, I have spotted it myself: 2.9.0 as override works: $ mix deps.get Resolving Hex dependencies... Dependency resolution completed: Unchanged: cowboy 2.8.0 cowlib 2.9.1 file_system 0.2.8 gettext 0.18.0 jason 1.2.1 mime 1.3.1 phoenix 1.5.3 phoenix_html 2.14.2 phoenix_live_da…

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Dependency error: Phoenix with gun

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LostKobrakai July 1, 2020, 6:38pm 18

Mix automatically locks to git commits.