Embedded elm-format is not found in globally installed plugin

[kachkaev]

Calling a bult-in elm-format binary fails when prettier-plugin-elm is installed globally. We need a slightly improved search mechanism for node_modules/.bin/elm-format in order to fix this. A temporary workaround involves installing elm-format in parallel to the plugin:

npm install --global prettier-plugin-elm elm-format
## or
yarn global add prettier-plugin-elm elm-format

(or elm-format@exp)

[avh4]

I tried to make guidelines for plugins to follow (avh4/elm-format#104), which currently says the following:

• Configuration

  • If the path to elm-format has not be explicitly specified by the user, the plugin should automatically find elm-format if it is located on the $PATH or in /usr/local/bin/.

    Is there an equivalent of /usr/local/bin/ for Windows?

    We should also add the path where npm install -g installs to, since this is the most common issue people have with plugin installation

  • If elm-format is not found, a message should be shown including a link to the elm-format installation instructions ( https://github.com/avh4/elm-format#installation- ). The message will be shown on the plugin settings screen if such a screen exists, and any time the user explicitly tries to format a file. The message may also be shown when the plugin is first installed or when saving an elm file.

I guess it needs to be updated to include a standard way for searching for elm-format installed with npm install -g, as you've noted. (Thought won't things installed that way generally be on the user's $PATH?)

[kachkaev]

Thanks for sharing the link @avh4!

When elm-format is installed globally via npm install --global elm-format, everything works fine. The case I'm mentioning in this issue is when you only run npm install --global prettier-plugin-elm, which in turn downloads and installs elm-format as its dependency to /usr/local/lib/node_modules/elm-format/. Unlike in local setups, there is no /usr/local/lib/node_modules/.bin folder, so spawning elm-format only involves a search in /usr/local/bin. This folder does not contain elm-format, because it has a status of a sub-dependency and npm decides not to pollute my global path with its binary.

Alternatively, I could move elm-format to peerDependencies and ask people to explicitly install it every time. But I guess it's better to keep this dependency tightly coupled with prettier-plugin-elm so save someone from using incompatible version pairs.

[kachkaev]

I believe this has been fixed in 6adc859, so there is no more need to install elm-format globally in order to make prettier-plugin-elm work.

Globally installed prettier still fails to load plugins due to prettier/prettier#4000, however, it is possible to install my fork while we are waiting for a new version that includes prettier/prettier#4192.