Fix plugin upgrade

Correctly decache all plugin paths

server/helpers/decache.ts

@@ -0,0 +1,78 @@
+// Thanks: https://github.com/dwyl/decache
+// We reuse this file to also uncache plugin base path
+
+import { extname } from 'path'
+
+function decachePlugin (pluginPath: string, libraryPath: string) {
+  const moduleName = find(libraryPath)
+
+  if (!moduleName) return
+
+  searchCache(moduleName, function (mod) {
+    delete require.cache[mod.id]
+  })
+
+  removeCachedPath(pluginPath)
+}
+
+function decacheModule (name: string) {
+  const moduleName = find(name)
+
+  if (!moduleName) return
+
+  searchCache(moduleName, function (mod) {
+    delete require.cache[mod.id]
+  })
+
+  removeCachedPath(moduleName)
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  decacheModule,
+  decachePlugin
+}
+
+// ---------------------------------------------------------------------------
+
+function find (moduleName: string) {
+  try {
+    return require.resolve(moduleName)
+  } catch {
+    return ''
+  }
+}
+
+function searchCache (moduleName: string, callback: (current: NodeModule) => void) {
+  const resolvedModule = require.resolve(moduleName)
+  let mod: NodeModule
+  const visited = {}
+
+  if (resolvedModule && ((mod = require.cache[resolvedModule]) !== undefined)) {
+    // Recursively go over the results
+    (function run (current) {
+      visited[current.id] = true
+
+      current.children.forEach(function (child) {
+        if (extname(child.filename) !== '.node' && !visited[child.id]) {
+          run(child)
+        }
+      })
+
+      // Call the specified callback providing the
+      // found module
+      callback(current)
+    })(mod)
+  }
+};
+
+function removeCachedPath (pluginPath: string) {
+  const pathCache = (module.constructor as any)._pathCache
+
+  Object.keys(pathCache).forEach(function (cacheKey) {
+    if (cacheKey.includes(pluginPath)) {
+      delete pathCache[cacheKey]
+    }
+  })
+}