tests: Pass --legacy-peer-deps flag to work around npm v7 bug

This flag is unknown to npm v6, but npm v6 silently ignores unknown
flags.

.github/workflows/backend-tests.yml

@@ -57,8 +57,10 @@ jobs:
         sudo apt install -y --no-install-recommends libreoffice libreoffice-pdfimport
 
     - name: Install Etherpad plugins
+      # The --legacy-peer-deps flag is required to work around a bug in npm v7:
+      # https://github.com/npm/cli/issues/2199
       run: >
-        npm install --no-save
+        npm install --no-save --legacy-peer-deps
         ep_align
         ep_author_hover
         ep_cursortrace
@@ -134,8 +136,10 @@ jobs:
         node-version: 12
 
     - name: Install Etherpad plugins
+      # The --legacy-peer-deps flag is required to work around a bug in npm v7:
+      # https://github.com/npm/cli/issues/2199
       run: >
-        npm install --no-save
+        npm install --no-save --legacy-peer-deps
         ep_align
         ep_author_hover
         ep_cursortrace

.github/workflows/frontend-admin-tests.yml

@@ -23,7 +23,9 @@ jobs:
 
     - name: Install etherpad plugins
       # We intentionally install an old ep_align version to test upgrades to the minor version number.
-      run: npm install --no-save ep_align@0.2.27
+      # The --legacy-peer-deps flag is required to work around a bug in npm v7:
+      # https://github.com/npm/cli/issues/2199
+      run: npm install --no-save --legacy-peer-deps ep_align@0.2.27
 
     # This must be run after installing the plugins, otherwise npm will try to
     # hoist common dependencies by removing them from src/node_modules and

.github/workflows/frontend-tests.yml

@@ -62,8 +62,10 @@ jobs:
       run: src/tests/frontend/travis/sauce_tunnel.sh
 
     - name: Install Etherpad plugins
+      # The --legacy-peer-deps flag is required to work around a bug in npm v7:
+      # https://github.com/npm/cli/issues/2199
       run: >
-        npm install --no-save
+        npm install --no-save --legacy-peer-deps
         ep_align
         ep_author_hover
         ep_cursortrace

.github/workflows/load-test.yml

@@ -51,8 +51,10 @@ jobs:
       run: sudo npm install -g etherpad-load-test
 
     - name: Install etherpad plugins
+      # The --legacy-peer-deps flag is required to work around a bug in npm v7:
+      # https://github.com/npm/cli/issues/2199
       run: >
-        npm install --no-save
+        npm install --no-save --legacy-peer-deps
         ep_align
         ep_author_hover
         ep_cursortrace

.travis.yml

@@ -28,8 +28,10 @@ _install_libreoffice: &install_libreoffice >-
   sudo apt-get update &&
   sudo apt-get -y install libreoffice libreoffice-pdfimport
 
+# The --legacy-peer-deps flag is required to work around a bug in npm v7:
+# https://github.com/npm/cli/issues/2199
 _install_plugins: &install_plugins >-
-  npm install --no-save
+  npm install --no-save --legacy-peer-deps
   ep_align
   ep_author_hover
   ep_cursortrace

README.md

@@ -115,7 +115,7 @@ Etherpad is very customizable through plugins. Instructions for installing theme
 Run the following command in your Etherpad folder to get all of the features visible in the demo gif:
 
 ```
-npm install --no-save ep_headings2 ep_markdown ep_comments_page ep_align ep_font_color ep_webrtc ep_embedded_hyperlinks2
+npm install --no-save --legacy-peer-deps ep_headings2 ep_markdown ep_comments_page ep_align ep_font_color ep_webrtc ep_embedded_hyperlinks2
 ```
 
 ## Customize the style with skin variants

doc/plugins.md

@@ -7,8 +7,8 @@ execute its own functionality based on these events.
 Publicly available plugins can be found in the npm registry (see
 <https://npmjs.org>). Etherpad's naming convention for plugins is to prefix your
 plugins with `ep_`. So, e.g. it's `ep_flubberworms`. Thus you can install
-plugins from npm, using `npm install --no-save ep_flubberworm` in Etherpad's
+plugins from npm, using `npm install --no-save --legacy-peer-deps
-root directory.
+ep_flubberworm` in Etherpad's root directory.
 
 You can also browse to `http://yourEtherpadInstan.ce/admin/plugins`, which will
 list all installed plugins and those available on npm. It even provides

src/bin/plugins/lib/README.md

@@ -9,7 +9,7 @@ Explain what your plugin does and who it's useful for.
 ## Installing
 
 ```
-npm install --no-save [plugin_name]
+npm install --no-save --legacy-peer-deps [plugin_name]
 ```
 
 or Use the Etherpad ``/admin`` interface.

src/static/js/pluginfw/installer.js

@@ -32,7 +32,9 @@ exports.uninstall = async (pluginName, cb = null) => {
   logger.info(`Uninstalling plugin ${pluginName}...`);
   try {
     // The --no-save flag prevents npm from creating package.json or package-lock.json.
-    await runCmd(['npm', 'uninstall', '--no-save', pluginName]);
+    // The --legacy-peer-deps flag is required to work around a bug in npm v7:
+    // https://github.com/npm/cli/issues/2199
+    await runCmd(['npm', 'uninstall', '--no-save', '--legacy-peer-deps', pluginName]);
   } catch (err) {
     logger.error(`Failed to uninstall plugin ${pluginName}`);
     cb(err || new Error(err));
@@ -49,7 +51,9 @@ exports.install = async (pluginName, cb = null) => {
   logger.info(`Installing plugin ${pluginName}...`);
   try {
     // The --no-save flag prevents npm from creating package.json or package-lock.json.
-    await runCmd(['npm', 'install', '--no-save', pluginName]);
+    // The --legacy-peer-deps flag is required to work around a bug in npm v7:
+    // https://github.com/npm/cli/issues/2199
+    await runCmd(['npm', 'install', '--no-save', '--legacy-peer-deps', pluginName]);
   } catch (err) {
     logger.error(`Failed to install plugin ${pluginName}`);
     cb(err || new Error(err));