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diff --git a/posts/2016/elm-everything-broken.md b/posts/2016/elm-everything-broken.md new file mode 100644 index 0000000..a9978d1 --- /dev/null +++ b/posts/2016/elm-everything-broken.md @@ -0,0 +1,427 @@ +Title: Everything Is Broken (Installing Elm Edition) +Author: bnewbold +Date: 2016-05-06 + +*This post is a narrative rant (in the same vein of Dan Luu's ["Everything is +Broken"][danluu] post) about my problems one afternoon getting a Fancy New +Programming Language to work on my laptop. [Skip down](#nowwhat) for my +thoughts on solutions.* + +[danluu]: https://danluu.com/everything-is-broken/ + +<br /> + +<div class="sidebar"> +<a href="https://www.youtube.com/watch?v=oYk8CKH7OhE"> +<img src="/static/fig/elm-evan-talk.jpg" alt="photo of E.C. giving an elm talk" width="240px" /> +</a> +</div> + +A few folks here at the [Recurse Center][rc] had nice things to say about the +[Elm programming language][rc], and after watching Evan Czaplicki's ["Let's Be +Mainstream" talk][0] I got pretty excited also. "Let's try Elm!" and the +adventure begins. + +[rc]: https://recurse.com/ +[elm]: https://elm-lang.org +[0]: https://www.youtube.com/watch?v=oYk8CKH7OhE + +First I go in the front door with the [install page][install], which redirects +me to a page which instructs me to use npm. + +[install]: http://elm-lang.org/install + +Hrm, I've had painful experiences with npm in the past, and anyways, isn't +the Elm compiler implemented in Haskell? Why are they using a package +management tool for Javascript libraries for installation? No thanks, I'll +[build from source][build], following these directions from the `README.md`: + +[build]: https://github.com/elm-lang/elm-platform + + # If you are on LINUX, you need to install a dependency of elm-repl. + # Uncomment the following line and run it. + # sudo apt-get install libtinfo-dev + + # if you are on windows, or some other place without curl, just download this file manually + curl https://raw.githubusercontent.com/elm-lang/elm-platform/master/installers/BuildFromSource.hs > BuildFromSource.hs + + runhaskell BuildFromSource.hs 0.16 + +<!-- If you don't know how to clone a repo, are you really going to know how to +get `cabal` set up, open a terminal and paste a command, etc? --> + +Weird that these build-from-source directions involve curl-to-file magics. Why +not just clone the repo and use a Makefile, which is roughly the same number of +commands to enter? I clone repo and run the build script from there instead. +I'm on Debian stable ("jessie"), so installing GHC (the most popular way to use +Haskell) is easy. I seem to have a recent-ish version of cabal: + +<pre class="terminal"> +bnewbold@eschaton$ cabal --version +cabal-install version 1.20.0.3 +using version 1.20.0.2 of the Cabal library +</pre> + +... so I think i'm ready to go ahead run the `BuildFromSource.hs` script: + +<pre class="terminal"> +bnewbold@eschaton$ runhaskell ~/src/elm-platform/installers/BuildFromSource.hs 0.16 + +GHCi runtime linker: fatal error: I found a duplicate definition for symbol +_hs_bytestring_long_long_uint_hex +whilst processing object file +/home/bnewbold/.cabal/lib/x86_64-linux-ghc-7.6.3/bytestring-0.10.6.0/HSbytestring-0.10.6.0.o +This could be caused by: +* Loading two different object files which export the same symbol +* Specifying the same object file twice on the GHCi command line +* An incorrect `package.conf' entry, causing some object to be + loaded twice. +GHCi cannot safely continue in this situation. Exiting now. Sorry. +</pre> + +Uh-oh! Not sure what that means. A search returns [a FAQ entry][faq-entry] +about "Duplicate Directions" which talks about linker flags, but *I* didn't +compile anything by hand so it doesn't seem like *I* have done anything wrong. +I'll try updating `cabal`'s package index: + +[faq-entry]: https://wiki.haskell.org/GHC/FAQ#Duplicate_Definitions + +<pre class="terminal"> +bnewbold@eschaton$ cabal update +Downloading the latest package list from hackage.haskell.org +cabal: Failed to download +http://hackage.haskell.org/packages/archive/00-index.tar.gz : ErrorMisc "Error +HTTP code: 502" +</pre> + +No go! At first I assumed I was doing something wrong, or maybe the WiFi was +flakey, but it turns out that the Hackage package repository [is +down](https://status.haskell.org/): + +> hackage.haskell.org down +> +> Full Service Disruption +> +> [Investigating] The hackage server is in an out of memory condition. We're investigating. + +<div class="sidebar"> +As far as I know, the only Debian packages out of the huge stable archive which +don't receive security updates are web browsers, mediawiki, and all V8/node.js +packages and libraries. +</div> + +Well, it wasn't even clear if updating my package index would fix the problem, +it was just a wild guess. I'll give up and try npm, which these days has been +[sort of packaged][deb-node] in Debian. I'll just uninstall npm when I'm done +installing Elm. I install with `apt` (which pulls in a huge list of `nodejs` +packages), but then can finally run: + +[deb-node]: https://www.debian.org/releases/stable/amd64/release-notes/ch-information.en.html#libv8 + +<pre class="terminal"> +bnewbold@eschaton$ npm install elm +| +> elm@0.16.0 install /home/bnewbold/bin/node_modules/elm +> node install.js + +sh: 1: node: not found +npm WARN This failure might be due to the use of legacy binary "node" +npm WARN For further explanations, please read +/usr/share/doc/nodejs/README.Debian + +npm ERR! elm@0.16.0 install: `node install.js` +npm ERR! Exit status 127 +npm ERR! +npm ERR! Failed at the elm@0.16.0 install script. +npm ERR! This is most likely a problem with the elm package, +npm ERR! not with npm itself. +npm ERR! Tell the author that this fails on your system: +npm ERR! node install.js +npm ERR! You can get their info via: +npm ERR! npm owner ls elm +npm ERR! There is likely additional logging output above. + +[...] +<!-- +npm ERR! System Linux 3.16.0-4-amd64 +npm ERR! command "/usr/bin/nodejs" "/usr/bin/npm" "install" "elm" +npm ERR! cwd /home/bnewbold/bin +npm ERR! node -v v0.10.29 +npm ERR! npm -v 1.4.21 +npm ERR! code ELIFECYCLE +npm ERR! +npm ERR! Additional logging details can be found in: +npm ERR! /home/bnewbold/bin/npm-debug.log +npm ERR! not ok code 0 +--> +</pre> + +<div class="sidebar"> +Later I learned that I could have instead installed the nodejs-legacy +package, which just installs a symlink /usr/bin/node which points to +/usr/bin/nodejs. +</div> + +Looks like Debian wants to refer to node.js as "`nodejs`" while npm/Elm expects +it to be "`node`". Ok, I create this shim named `node` in my `~/bin` directory +(which is on my `$PATH`), and make it executable: + +<pre class="terminal"> +#!/bin/sh +nodejs $* +</pre> + +Now I can do things like: + +<pre class="terminal"> +bnewbold@eschaton$ node --version +v0.10.29 +</pre> + +Great! Now let's install Elm with npm! + +<pre class="terminal"> +bnewbold@eschaton$ npm install elm + +> elm@0.16.0 install /home/bnewbold/bin/node_modules/elm +> node install.js + +Downloading Elm Reactor assets from https://dl.bintray.com/elmlang/elm-platform/0.16.0/elm-reactor-assets.tar.gz +Error communicating with URL https://dl.bintray.com/elmlang/elm-platform/0.16.0/linux-x64.tar.gz Error: CERT_UNTRUSTED +npm WARN This failure might be due to the use of legacy binary "node" +npm WARN For further explanations, please read +/usr/share/doc/nodejs/README.Debian + +npm ERR! elm@0.16.0 install: `node install.js` +npm ERR! Exit status 1 +npm ERR! +npm ERR! Failed at the elm@0.16.0 install script. +npm ERR! This is most likely a problem with the elm package, +npm ERR! not with npm itself. +npm ERR! Tell the author that this fails on your system: +npm ERR! node install.js +npm ERR! You can get their info via: +npm ERR! npm owner ls elm +npm ERR! There is likely additional logging output above. + +npm ERR! System Linux 3.16.0-4-amd64 +npm ERR! command "/usr/bin/nodejs" "/usr/bin/npm" "install" "elm" +npm ERR! cwd /home/bnewbold/bin +npm ERR! node -v v0.10.29 +npm ERR! npm -v 1.4.21 +npm ERR! code ELIFECYCLE +npm ERR! +npm ERR! Additional logging details can be found in: +npm ERR! /home/bnewbold/bin/npm-debug.log +npm ERR! not ok code 0 +</pre> + +Whoops. There is [a github issue][elm-issue] that has some tips about this: the +recommended solutions online are basically "upgrade node.js and npm" or +"disable SSL security". That doesn't sound great, but i'm feeling very +impatient at this point so I tried disabling SSL checks with `npm config set ca +null`, but even then I get the certificate error. Enough of that approach: + +[elm-issue]: https://github.com/elm-lang/elm-platform/issues/100 + +<pre class="terminal"> +sudo apt remove npm nodejs +rm ~/bin/node +</pre> + +Poking around a bit more, I find the promisingly-titled "`fubar.sh`" script in +the `elm-platform` repo cloned earlier, which seems to nuke the local user's +Haskell (`cabal`) stuff (but doesn't muck with system-wide package, eg `apt` +managed GHC libraries). After running `fubar.sh` the `BuildFromSource.hs` +script seems to start working (success!), but Hackage is still down (now, an +hour after I started this process, approaching 5 hours total downtime), so I +can't install dependencies. + +I search for a hackage mirror and find that [FPComplete runs +one](https://www.fpcomplete.com/blog/2015/03/hackage-mirror). In addition to +their configuration instructions I had to set `remote-repo-cache` in my +`~/.cabal/config`, like so: + + remote-repo: hackage.fpcomplete.com:http://hackage.fpcomplete.com/ + remote-repo-cache: /home/bnewbold/.cabal/packages-fpcomplete + +After that I `cabal update` and run the `BuildFromSource.hs` script again. It +fails to build the dependency `websockets-snap`, but I try installing that +regularly (`cabal install websockets-snap`) and that works, and then all the +dependencies with BuildFromSource.hs build. Yay! + +I still get an error with compiling Elm itself though: + + src/Elm/Package.hs:60:25: + Not in scope: `<$>' + Perhaps you meant `</>' (imported from System.FilePath) + +It [sounds like](https://github.com/elm-lang/elm-platform/issues/30) I am using +an out of date version of GHC (the Haskell compiler): I have 7.6.3 (the version +that comes with Debian), and Elm wants 7.10. Fair enough: unlike a package +manager, I can see how new features in the compiler would be helpful, and when +I go back and check this was outlined in the README. Fortunately there is a new +version of GHC in the `jessie-backports` repo, so: + +<pre class="terminal"> +sudo apt install -t jessie-backports ghc +</pre> + +And now: + +<pre class="terminal"> +bnewbold@eschaton$ cabal --version +cabal-install version 1.22.6.0 +using version 1.22.5.0 of the Cabal library +bnewbold@eschaton$ ghc --version +The Glorious Glasgow Haskell Compilation System, version 7.10.3 +</pre> + +After that, I'm miraculously able to compile. Horray! I add +`~/bin/Elm-Platform/0.16/.cabal-sandbox/bin` to my `$PATH` and I can run: + +<pre class="terminal"> +bnewbold@eschaton$ elm-repl +---- elm repl 0.16.0 ----------------------------------------------------------- +:help for help, :exit to exit, more at <https://github.com/elm-lang/elm-repl> +-------------------------------------------------------------------------------- +> +</pre> + +Success! + +To be clear, once I got this far I had few or no problems with Elm. The +language seems reasonably clean and well documented for it's maturity, and it +was only this install procress that felt horribly broken. + +Throughout this debugging process I had problems with both my external [Lenovo +Thinkpad USB keyboard][keyboard] glitching (workaround: unplug and re-plug) and +with WiFi at the Recurse Center disconnecting (workaround: reset wifi card). +Others here using GNU/Linux have the same wifi problems, but we don't have a +fix yet... something to do with wireless regulatory zones. + +It's not all pain though; installing the `elm.vim` syntax highlighting plugin +was very easy, just a single `git clone` into `~/.vim/bundle/`. + +[keyboard]: https://www.amazon.com/Lenovo-ThinkPad-Compact-Keyboard-TrackPoint/dp/B00F3U4TQS + +<a name="nowwhat" /> + +So Now What? +---------------- + +There was a great long-form blog post by Sam Boyer a few months ago ("[So You +Want To Write a Package Manager][5]") which describes the jumble of *system*, +*language*, and *project* dependency manager problems I experienced above. Sam +basically concludes that Rust's project/language dependency manager (Cargo) +both encapsulates best practices for dependable and reproducible builds, while +still allowing rapid evolution of a package "ecosystem". Cargo was designed by +[Yehuda Katz and Carl Lerche][6], and along with the +[crates.io](https://crates.io) archive it does sound very nice. My personal +feeling are usually that system-wide package managers (like Debian's `apt`) are +underappreciated by many young-but-not-bleeding-edge projects, but acknowledge +that there probably is also a need for higher tempo cross-platform project +dependency mangement for non-library projects (eg, desktop applications and web +apps). + +Ironically (given the difficulty I had installing it), the Elm language's +package manager has a great `diff` tool for checking that any changes in the +API conform to the [documented][8] [semantic versioning][semver] conventions. +For [example](https://gist.github.com/badboy/a302dd0c9020e5759240): + + $ elm-package diff evancz/elm-html 3.0.0 4.0.2 + Comparing evancz/elm-html 3.0.0 to 4.0.2... + This is a MAJOR change. + + ------ Changes to module Html.Attributes - MAJOR ------ + + Removed: + boolProperty : String -> Bool -> Attribute + stringProperty : String -> String -> Attribute + + + ------ Changes to module Html.Events - MINOR ------ + + Added: + type alias Options = + { stopPropagation : Bool, preventDefault : Bool } + defaultOptions : Html.Events.Options + onWithOptions : String -> Html.Events.Options -> Json.Decode.Decoder a -> (a -> Signal.Message) -> Html.Attribute + +This API change information is then used to *[programatically enforce][7]* the +semantic versioning rules for submissions to the Elm language library archive +and prevent a whole class of simple but annoying breakages due to unexpected +API changes. It can't detect *every* breaking change (eg, those which are +internal), but it can detect enough to be worth the effort. + +Another option for detecting fixing breakage is integration testing at the +package ecosystem level. Debian's [reproducible builds][repro] effort has built +out one such system, and continues to catch thousands of "failed to build from +source" (FTBFS) bugs along the way. Dan Luu's ["Everything is Broken"][danluu] +blog post (which to some degree inspired this one) mostly focused on the lack +of quality tests for many contemporary software projects, and proposed the use +of smart fuzzing and heuristically-generated tests to work around the huge +technical debt this represents. As far as I can tell there are hardly ever +automated integration tests for entire package archives; blame for dependency +problems is usually attributed to a bug in one package (instead of being seen +as a systemic failure), and such problems are seen as an unavoidable cost of +rapid and distributed development. + +I think we can do better. For example, some contemporary languages test +compiler changes for regressions against a broad snapshot of public code +written in that language; I know Go and Rust specifically do this to identify +problems before compiler releases, and the Python community occasionally runs +tests against the PyPi archive when considering syntax changes or feature +deprecations. And Debian's unstable and testing archives enforce a waiting +period so that human testers can turn up conflicts before packages can be moved +into stable or backports. I think we can and should automate these processes as +much as possible, and give direct feedback to library developers and package +maintainers when they push updates. Commercial Continuous Integration services +like Travis CI and Circle CI should offer more common target platforms (eg, ARM +architecture, more versions of distributions), and if they don't we should +build and host our own testing infrastructure. CI builds scripts should closely +match the official installation instructions for a given platform, so we catch +problems with those instructions quickly. + +We have more and more developers in the world wasting more and more days +wrangling with dependency hell, but despite that I think we're closer than ever +to taming the beast. + +[5]: https://medium.com/@sdboyer/so-you-want-to-write-a-package-manager-4ae9c17d9527 +[6]: https://mail.mozilla.org/pipermail/rust-dev/2014-March/009090.html +[7]: https://github.com/elm-lang/elm-package/blob/master/README.md#version-rules +[8]: https://github.com/elm-lang/elm-package/blob/master/README.md#publishing-updates +[semver]: http://semver.org/ +[appcheck]: http://www.linuxfoundation.org/collaborate/workgroups/lsb/linux-application-checker-getting-started +[repro]: https://tests.reproducible-builds.org/debian/reproducible.html + +<hr /> + +#### Follow up June 18th, 2016 + +A few days after writing this post, a new version of Elm (0.17) was +[released](http://elm-lang.org/blog/farewell-to-frp). The new version made some +big changes, like abandoning the [Functional Reactive Programming][frp] +paradigm. I found that many of the new tutorials weren't working with my 0.16 +install, so I tried to upgrade. After an hour or two of following the +directions above, I gave up and installed npm on a temporary Debian unstable +("sid") virtual machine. Once I added a `node` symlink to `nodejs`, I was able +to install `elm` with npm and develop remotely using `screen` and +`elm-react`. Frustrating! + +[frp]: https://en.wikipedia.org/wiki/Functional_reactive_programming + +<br /> +<center style="font-size: smaller;"> +<img src="/static/fig/status_haskell_broken.png" width="600px" /> +<br /> +Also, status.haskell.org seems to be broken again today, though +the hackage website works. +</center> + +On the plus side, my USB keyboard problem seems to have been due to the cheap +random USB cable I was using. Since replacing it I haven't had the bad +flakey-ness, though now after my laptop awakes from sleep the pointer and +keyboard work but the middle mouse button ("paste" on UNIX) does not. +Workaround: plug and unplug the whole keyboard. + |