Deactivate plugins before recreating a new composer instance and loading new plugins in require/remove commands, fixes #9962

src/Composer/Command/RemoveCommand.php

@@ -210,6 +210,10 @@ EOT
             return 0;
         }
 
+        if ($composer = $this->getComposer(false)) {
+            $composer->getPluginManager()->deactivateInstalledPlugins();
+        }
+
         // Update packages
         $this->resetComposer();
         $composer = $this->getComposer(true, $input->getOption('no-plugins'));

src/Composer/Command/RequireCommand.php

@@ -278,6 +278,8 @@ EOT
             return 0;
         }
 
+        $composer->getPluginManager()->deactivateInstalledPlugins();
+
         try {
             return $this->doUpdate($input, $output, $io, $requirements, $requireKey, $removeKey);
         } catch (\Exception $e) {

src/Composer/Plugin/PluginManager.php

@@ -90,6 +90,25 @@ class PluginManager
         }
     }
 
+    /**
+     * Deactivate all plugins from currently installed plugin packages
+     *
+     * @return void
+     */
+    public function deactivateInstalledPlugins()
+    {
+        if ($this->disablePlugins) {
+            return;
+        }
+
+        $repo = $this->composer->getRepositoryManager()->getLocalRepository();
+        $globalRepo = $this->globalComposer ? $this->globalComposer->getRepositoryManager()->getLocalRepository() : null;
+        $this->deactivateRepository($repo, false);
+        if ($globalRepo) {
+            $this->deactivateRepository($globalRepo, true);
+        }
+    }
+
     /**
      * Gets all currently active plugin instances
      *
@@ -428,6 +447,34 @@ class PluginManager
         }
     }
 
+    /**
+     * Deactivate all plugins and installers from a repository
+     *
+     * If a plugin requires another plugin, the required one will be deactivated last
+     *
+     * @param RepositoryInterface $repo Repository to scan for plugins to install
+     * @param bool                $isGlobalRepo
+     *
+     * @return void
+     */
+    private function deactivateRepository(RepositoryInterface $repo, $isGlobalRepo)
+    {
+        $packages = $repo->getPackages();
+        $sortedPackages = array_reverse(PackageSorter::sortPackages($packages));
+
+        foreach ($sortedPackages as $package) {
+            if (!($package instanceof CompletePackage)) {
+                continue;
+            }
+            if ('composer-plugin' === $package->getType()) {
+                $this->deactivatePackage($package);
+            // Backward compatibility
+            } elseif ('composer-installer' === $package->getType()) {
+                $this->deactivatePackage($package);
+            }
+        }
+    }
+
     /**
      * Recursively generates a map of package names to packages for all deps
      *