path: root/posts/elm-everything-broken.md

Title: Everything Is Broken (Installing Elm Edition)
Author: bnewbold
Date: 2016-05-06
Status: draft

*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 to the end for my thoughts on a
solution.*

[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!

[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 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 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". It doesn't seem like *I* have done anything
wrong. I'll update `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>

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 a set of web browser, mediawiki, and all
V8/node.js packages and libraries.
</div>

Well, wasn't even sure if updating my package index would fix the problem. 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 call node.js `nodejs` while npm/Elm expects it to
be called `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 same 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, though 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 directions 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, 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 look this is 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!

Throughout this debugging experience 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

So Now What?
----------------

TODO: dan's auto-testing tips

There was a great long-form blog post by Same Boyer a few months ago
(["So You Want To Write a Package Manager"][5]) which discussed Rust's package
manager, Cargo.

[Yehuda Katz and Carl Lerche][6] designed Cargo.

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 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 change information is then used to *[programatically enforce][7]* the
versioning rules and prevent a whole class of simple but annoying  breakages
due to API change.

[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

<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.