Add support for formatters locally installed via yarn 2+ pnp mode (#200)

This adds support for formatters installed locally in project
directories via yarn 2's "zero install" [pnp
mode](https://yarnpkg.com/features/pnp).

It's quite similar to the support for formatters installed locally in a
project's `node_modules` via npm, and leverages the `npx` symbol, so
existing formatter definitions should work without modification.

This checks for a `.pnp.cjs` file (expected in the project root for yarn
pnp projects), then looks for a yarn executable, and checks the version
of yarn to make sure it supports pnp. If that works, we just push
`"yarn"` onto the front of `command`.

I've only tested this with a locally installed `prettier.js`. It's very
much a works-for-me draft, I'm putting in a PR to make sure this is a
workable approach before going any further with it.

---------

Co-authored-by: Radon Rosborough <radon@intuitiveexplanations.com>

4 files changed, 25 insertions, 26 deletions

diff --git a/test/formatters/apheleia-ft.el b/test/formatters/apheleia-ft.el
index 5396115..a8ac9d4 100755
--- a/test/formatters/apheleia-ft.el
+++ b/test/formatters/apheleia-ft.el
@@ -101,11 +101,12 @@ relative to repo root, as returned by git diff --name-only."
      ((string-match
        "^scripts/formatters/\\([^/]+\\)$" changed-file)
       (let ((script (match-string 1 changed-file)))
-        (map-keys
-         (map-filter
-          (lambda (fmt def)
-            (member script def))
-          apheleia-formatters)))))))
+        (mapcar #'symbol-name
+                (map-keys
+                 (map-filter
+                  (lambda (fmt def)
+                    (and (listp def) (member script def)))
+                  apheleia-formatters))))))))
 
 (defun apheleia-ft--get-formatters-for-pull-request ()
   "Return list of formatter string names that were touched in this PR.
@@ -133,7 +134,10 @@ main."
   "Print to stdout a comma-delimited list of formatters changed in this PR."
   (princ (concat
           (string-join
-           (apheleia-ft--get-formatters-for-pull-request) ",")
+           (cl-remove-duplicates
+            (apheleia-ft--get-formatters-for-pull-request)
+            :test 'string=)
+           ",")
           "\n")))
 
 (defun apheleia-ft--read-file (filename)
diff --git a/test/formatters/install-common.bash b/test/formatters/install-common.bash
index 113e7ac..6b4489d 100755
--- a/test/formatters/install-common.bash
+++ b/test/formatters/install-common.bash
@@ -6,14 +6,10 @@ export DEBIAN_FRONTEND=noninteractive
 apt-get update
 apt-get install -y ca-certificates curl gnupg lsb-release software-properties-common
 
-curl -fsSL https://deb.nodesource.com/gpgkey/nodesource.gpg.key | apt-key add -
-
-ubuntu_name="$(lsb_release -cs)"
-node_repo="$(curl -fsSL https://deb.nodesource.com/setup_current.x | grep NODEREPO= | grep -Eo 'node_[0-9]+\.x' | head -n1)"
-
-tee -a /etc/apt/sources.list.d/nodejs.list >/dev/null <<EOF
-deb [arch=amd64] https://deb.nodesource.com/${node_repo} ${ubuntu_name} main
-EOF
+mkdir -p /etc/apt/keyrings
+curl -fsSL https://deb.nodesource.com/gpgkey/nodesource-repo.gpg.key | gpg --dearmor -o /etc/apt/keyrings/nodesource.gpg
+NODE_MAJOR=20
+echo "deb [signed-by=/etc/apt/keyrings/nodesource.gpg] https://deb.nodesource.com/node_$NODE_MAJOR.x nodistro main" | tee /etc/apt/sources.list.d/nodesource.list
 
 add-apt-repository -n ppa:longsleep/golang-backports
 
@@ -30,9 +26,6 @@ nodejs
 sudo
 unzip
 wget
-sudo
-unzip
-wget
 
 "
 
diff --git a/test/formatters/installers/prettier-ruby.bash b/test/formatters/installers/prettier-ruby.bash
index 611f5c6..9351a44 100644
--- a/test/formatters/installers/prettier-ruby.bash
+++ b/test/formatters/installers/prettier-ruby.bash
@@ -1,15 +1,16 @@
 # Need ruby for gem, need gcc and ruby headers for native gem deps
 apt-get install -y ruby ruby-dev gcc
 
-# Install the plugin
-npm install -g prettier @prettier/plugin-ruby
-
-# Have to install from source because release not tagged yet
-# https://github.com/ruby-syntax-tree/syntax_tree-rbs/pull/34
-# https://stackoverflow.com/a/11767563
-gem install specific_install
-gem specific_install -l https://github.com/ruby-syntax-tree/syntax_tree-rbs.git
+# Apparently rubygems does not know how to do dependency resolution.
+# So we have to manually install an old version of this dependency to
+# avoid the latest version getting installed and then failing to build
+# because it does not support ruby 2.7 which is what we have.
+gem install rbs -v 3.1.3
 
 # These are required dependencies documented at
 # https://www.npmjs.com/package/@prettier/plugin-ruby
 gem install prettier_print syntax_tree syntax_tree-haml syntax_tree-rbs
+
+# Install the plugin
+cd /tmp
+npm install --save-dev prettier @prettier/plugin-ruby
diff --git a/test/formatters/installers/prettier-svelte.bash b/test/formatters/installers/prettier-svelte.bash
index 70fae61..1ab0809 100644
--- a/test/formatters/installers/prettier-svelte.bash
+++ b/test/formatters/installers/prettier-svelte.bash
@@ -1 +1,2 @@
-npm install -g prettier-plugin-svelte prettier
+cd /tmp
+npm install --save-dev prettier-plugin-svelte prettier