yarnInstallHook: init (#328544)

doc/languages-frameworks/javascript.section.md

@@ -467,6 +467,7 @@ Yarn based projects use a `yarn.lock` file instead of a `package-lock.json` to p
 
 - `yarnConfigHook`: Fetches the dependencies from the offline cache and installs them into `node_modules`.
 - `yarnBuildHook`: Runs `yarn build` or a specified `yarn` command that builds the project.
+- `yarnInstallHook`: Runs `yarn install --production` to prune dependencies and installs the project into `$out`.
 
 An example usage of the above attributes is:
 
@@ -501,9 +502,9 @@ stdenv.mkDerivation (finalAttrs: {
   nativeBuildInputs = [
     yarnConfigHook
     yarnBuildHook
+    yarnInstallHook
     # Needed for executing package.json scripts
     nodejs
-    npmHooks.npmInstallHook
   ];
 
   meta = {
@@ -512,8 +513,6 @@ stdenv.mkDerivation (finalAttrs: {
 })
 ```
 
-Note that there is no setup hook for installing yarn based packages - `npmHooks.npmInstallHook` should fit most cases, but sometimes you may need to override the `installPhase` completely.
-
 #### `yarnConfigHook` arguments {#javascript-yarnconfighook}
 
 By default, `yarnConfigHook` relies upon the attribute `${yarnOfflineCache}` (or `${offlineCache}` if the former is not set) to find the location of the offline cache produced by `fetchYarnDeps`. To disable this phase, you can set `dontYarnInstallDeps = true` or override the `configurePhase`.
@@ -525,9 +524,15 @@ This script by default runs `yarn --offline build`, and it relies upon the proje
 - `yarnBuildScript`: Sets a different `yarn --offline` subcommand (defaults to `build`).
 - `yarnBuildFlags`: Single string list of additional flags to pass the above command, or a Nix list of such additional flags.
 
+#### `yarnInstallHook` arguments {#javascript-yarninstallhook}
+
+To install the package `yarnInstallHook` uses both `npm` and `yarn` to cleanup project files and dependencies. To disable this phase, you can set `dontYarnInstall = true` or override the `installPhase`. Below is a list of additional `mkDerivation` arguments read by this hook:
+
+- `yarnKeepDevDeps`: Disables the removal of devDependencies from `node_modules` before installation.
+
 ### yarn2nix {#javascript-yarn2nix}
 
-WARNING: The `yarn2nix` functions have been deprecated in favor of the new `yarnConfigHook` and `yarnBuildHook`. Documentation for them still appears here for the sake of the packages that still use them. See also a tracking issue [#324246](/~https://github.com/NixOS/nixpkgs/issues/324246).
+WARNING: The `yarn2nix` functions have been deprecated in favor of the new `yarnConfigHook`, `yarnBuildHook` and `yarnInstallHook`. Documentation for them still appears here for the sake of the packages that still use them. See also a tracking issue [#324246](/~https://github.com/NixOS/nixpkgs/issues/324246).
 
 #### Preparation {#javascript-yarn2nix-preparation}
 

pkgs/build-support/node/fetch-yarn-deps/default.nix

@@ -2,9 +2,14 @@
   stdenv,
   lib,
   makeWrapper,
+  installShellFiles,
+  nodejsInstallManuals,
+  nodejsInstallExecutables,
   coreutils,
   nix-prefetch-git,
   fetchurl,
+  jq,
+  nodejs,
   nodejs-slim,
   prefetch-yarn-deps,
   fixup-yarn-lock,
@@ -175,4 +180,16 @@ in
       description = "Run yarn build in buildPhase";
     };
   } ./yarn-build-hook.sh;
+
+  yarnInstallHook = makeSetupHook {
+    name = "yarn-install-hook";
+    propagatedBuildInputs = [
+      yarn
+      nodejsInstallManuals
+      nodejsInstallExecutables
+    ];
+    substitutions = {
+      jq = lib.getExe jq;
+    };
+  } ./yarn-install-hook.sh;
 }

pkgs/build-support/node/fetch-yarn-deps/yarn-install-hook.sh

@@ -0,0 +1,79 @@
+# shellcheck shell=bash
+
+yarnInstallHook() {
+    echo "Executing yarnInstallHook"
+
+    runHook preInstall
+
+    local -r packageOut="$out/lib/node_modules/$(@jq@ --raw-output '.name' ./package.json)"
+    mkdir -p "$packageOut"
+
+    local -ar yarnArgs=(
+        --ignore-engines
+        --ignore-platform
+        --ignore-scripts
+        --no-progress
+        --non-interactive
+        --offline
+    )
+
+    local -r tmpDir="$(mktemp -d yarnInstallHook.XXXXXX)"
+
+    # yarn pack does not work at all with bundleDependencies.
+    # Since we are imediately unpacking, we can just remove them from package.json
+    # This will NOT be fixed in yarn v1: /~https://github.com/yarnpkg/yarn/issues/6794
+    mv ./package.json "$tmpDir/package.json.orig"
+    # Note: two spellings are accepted, 'bundleDependencies' and 'bundledDependencies'
+    @jq@ 'del(.bundleDependencies)|del(.bundledDependencies)' "$tmpDir/package.json.orig" > ./package.json
+
+    # TODO: figure out a way to avoid redundant compress/decompress steps
+    yarn pack \
+        --filename "$tmpDir/yarn-pack.tgz" \
+        "${yarnArgs[@]}"
+
+    tar xzf "$tmpDir/yarn-pack.tgz" \
+        -C "$packageOut" \
+        --strip-components 1 \
+        package/
+
+    mv "$tmpDir/package.json.orig" ./package.json
+
+    nodejsInstallExecutables ./package.json
+
+    nodejsInstallManuals ./package.json
+
+    local -r nodeModulesPath="$packageOut/node_modules"
+
+    if [ ! -d "$nodeModulesPath" ]; then
+        if [ -z "${yarnKeepDevDeps-}" ]; then
+            # Yarn has a 'prune' command, but it's only a stub that directs you to use install
+            if ! yarn install \
+                --frozen-lockfile \
+                --force \
+                --production=true \
+                "${yarnArgs[@]}"
+            then
+              echo
+              echo
+              echo "ERROR: yarn prune step failed"
+              echo
+              echo 'If yarn tried to download additional dependencies above, try setting `yarnKeepDevDeps = true`.'
+              echo
+
+              exit 1
+            fi
+        fi
+
+        find node_modules -maxdepth 1 -type d -empty -delete
+
+        cp -r node_modules "$nodeModulesPath"
+    fi
+
+    runHook postInstall
+
+    echo "Finished yarnInstallHook"
+}
+
+if [ -z "${dontYarnInstall-}" ] && [ -z "${installPhase-}" ]; then
+    installPhase=yarnInstallHook
+fi