diff --git a/doc/articles/scripts.md b/doc/articles/scripts.md
index c16977003..8977aa32d 100644
--- a/doc/articles/scripts.md
+++ b/doc/articles/scripts.md
@@ -43,8 +43,8 @@ Composer fires the following named events during its execution process:
 
 ### Installer Events
 
-- **pre-dependencies-solving**: occurs before the dependencies are resolved.
-- **post-dependencies-solving**: occurs after the dependencies have been resolved.
+- **pre-operations-exec**: occurs before the install/upgrade/.. operations
+  are executed when installing a lock file.
 
 ### Package Events
 
diff --git a/src/Composer/EventDispatcher/EventDispatcher.php b/src/Composer/EventDispatcher/EventDispatcher.php
index 34a1981a9..fda5c29fd 100644
--- a/src/Composer/EventDispatcher/EventDispatcher.php
+++ b/src/Composer/EventDispatcher/EventDispatcher.php
@@ -119,20 +119,17 @@ class EventDispatcher
     /**
      * Dispatch a installer event.
      *
-     * @param string              $eventName     The constant in InstallerEvents
-     * @param bool                $devMode       Whether or not we are in dev mode
-     * @param PolicyInterface     $policy        The policy
-     * @param RepositorySet       $repositorySet The repository set
-     * @param RepositoryInterface $localRepo     The installed repository
-     * @param Request             $request       The request
-     * @param array               $operations    The list of operations
+     * @param string              $eventName         The constant in InstallerEvents
+     * @param bool                $devMode           Whether or not we are in dev mode
+     * @param bool                $executeOperations True if operations will be executed, false in --dry-run
+     * @param Transaction         $transaction       The transaction contains the list of operations
      *
      * @return int return code of the executed script if any, for php scripts a false return
      *             value is changed to 1, anything else to 0
      */
-    public function dispatchInstallerEvent($eventName, $devMode, RepositorySet $repositorySet, Pool $pool, Request $request, PolicyInterface $policy, Transaction $transaction = null)
+    public function dispatchInstallerEvent($eventName, $devMode, $executeOperations, Transaction $transaction)
     {
-        return $this->doDispatch(new InstallerEvent($eventName, $this->composer, $this->io, $devMode, $repositorySet, $pool, $request, $policy, $transaction));
+        return $this->doDispatch(new InstallerEvent($eventName, $this->composer, $this->io, $devMode, $executeOperations, $transaction));
     }
 
     /**
diff --git a/src/Composer/Installer.php b/src/Composer/Installer.php
index b7ee247db..a1f93695d 100644
--- a/src/Composer/Installer.php
+++ b/src/Composer/Installer.php
@@ -382,7 +382,6 @@ class Installer
         }
 
         $pool = $repositorySet->createPool($request, $this->eventDispatcher);
-        $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::PRE_DEPENDENCIES_SOLVING, $this->devMode, $repositorySet, $pool, $request, $policy);
 
         // solve dependencies
         $solver = new Solver($policy, $pool, $this->io, $repositorySet);
@@ -400,9 +399,6 @@ class Installer
             return max(1, $e->getCode());
         }
 
-        // TODO should we warn people / error if plugins in vendor folder do not match contents of lock file before update?
-        $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, $this->devMode, $repositorySet, $pool, $request, $policy, $lockTransaction);
-
         $this->io->writeError("Analyzed ".count($pool)." packages to resolve dependencies", true, IOInterface::VERBOSE);
         $this->io->writeError("Analyzed ".$ruleSetSize." rules to resolve dependencies", true, IOInterface::VERBOSE);
 
@@ -524,11 +520,9 @@ class Installer
 
         $pool = $repositorySet->createPool($request, $this->eventDispatcher);
 
-        $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::PRE_DEPENDENCIES_SOLVING, false, $repositorySet, $pool, $request, $policy);
         $solver = new Solver($policy, $pool, $this->io, $repositorySet);
         try {
             $nonDevLockTransaction = $solver->solve($request, $this->ignorePlatformReqs);
-            $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, false, $repositorySet, $pool, $request, $policy, $nonDevLockTransaction);
             $solver = null;
         } catch (SolverProblemsException $e) {
             $this->io->writeError('<error>Unable to find a compatible set of packages based on your non-dev requirements alone.</error>', true, IOInterface::QUIET);
@@ -547,22 +541,22 @@ class Installer
      */
     protected function doInstall(RepositoryInterface $localRepo, $alreadySolved = false)
     {
-        $platformRepo = $this->createPlatformRepo(false);
-        $lockedRepository = $this->locker->getLockedRepository($this->devMode);
-
-        // creating repository set
-        $policy = $this->createPolicy(false);
-        // use aliases from lock file only, so empty root aliases here
-        $repositorySet = $this->createRepositorySet(false, $platformRepo, array(), $lockedRepository);
-        $repositorySet->addRepository($lockedRepository);
-
         $this->io->writeError('<info>Installing dependencies from lock file'.($this->devMode ? ' (including require-dev)' : '').'</info>');
 
+        $lockedRepository = $this->locker->getLockedRepository($this->devMode);
+
         // verify that the lock file works with the current platform repository
         // we can skip this part if we're doing this as the second step after an update
         if (!$alreadySolved) {
             $this->io->writeError('<info>Verifying lock file contents can be installed on current platform.</info>');
 
+            $platformRepo = $this->createPlatformRepo(false);
+            // creating repository set
+            $policy = $this->createPolicy(false);
+            // use aliases from lock file only, so empty root aliases here
+            $repositorySet = $this->createRepositorySet(false, $platformRepo, array(), $lockedRepository);
+            $repositorySet->addRepository($lockedRepository);
+
             // creating requirements request
             $request = $this->createRequest($this->fixedRootPackage, $platformRepo, $lockedRepository);
 
@@ -579,7 +573,6 @@ class Installer
             }
 
             $pool = $repositorySet->createPool($request, $this->eventDispatcher);
-            $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::PRE_DEPENDENCIES_SOLVING, $this->devMode, $repositorySet, $pool, $request, $policy);
 
             // solve dependencies
             $solver = new Solver($policy, $pool, $this->io, $repositorySet);
@@ -599,13 +592,11 @@ class Installer
 
                 return max(1, $e->getCode());
             }
-
-            // TODO should we warn people / error if plugins in vendor folder do not match contents of lock file before update?
-            $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, $this->devMode, $repositorySet, $pool, $request, $policy, $lockTransaction);
         }
 
         // TODO in how far do we need to do anything here to ensure dev packages being updated to latest in lock without version change are treated correctly?
         $localRepoTransaction = new LocalRepoTransaction($lockedRepository, $localRepo);
+        $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::PRE_OPERATIONS_EXEC, $this->devMode, $this->executeOperations, $localRepoTransaction);
 
         if (!$localRepoTransaction->getOperations()) {
             $this->io->writeError('Nothing to install, update or remove');
diff --git a/src/Composer/Installer/InstallerEvent.php b/src/Composer/Installer/InstallerEvent.php
index 7fc5fe746..1b8f03de4 100644
--- a/src/Composer/Installer/InstallerEvent.php
+++ b/src/Composer/Installer/InstallerEvent.php
@@ -21,11 +21,6 @@ use Composer\EventDispatcher\Event;
 use Composer\IO\IOInterface;
 use Composer\Repository\RepositorySet;
 
-/**
- * An event for all installer.
- *
- * @author François Pluchino <francois.pluchino@gmail.com>
- */
 class InstallerEvent extends Event
 {
     /**
@@ -44,27 +39,12 @@ class InstallerEvent extends Event
     private $devMode;
 
     /**
-     * @var RepositorySet
+     * @var bool
      */
-    private $repositorySet;
+    private $executeOperations;
 
     /**
-     * @var Pool
-     */
-    private $pool;
-
-    /**
-     * @var Request
-     */
-    private $request;
-
-    /**
-     * @var PolicyInterface
-     */
-    private $policy;
-
-    /**
-     * @var Transaction|null
+     * @var Transaction
      */
     private $transaction;
 
@@ -75,23 +55,17 @@ class InstallerEvent extends Event
      * @param Composer             $composer
      * @param IOInterface          $io
      * @param bool                 $devMode
-     * @param RepositorySet        $repositorySet
-     * @param Pool                 $pool
-     * @param Request              $request
-     * @param PolicyInterface      $policy
+     * @param bool                 $executeOperations
      * @param Transaction          $transaction
      */
-    public function __construct($eventName, Composer $composer, IOInterface $io, $devMode, RepositorySet $repositorySet, Pool $pool, Request $request, PolicyInterface $policy, Transaction $transaction = null)
+    public function __construct($eventName, Composer $composer, IOInterface $io, $devMode, $executeOperations, Transaction $transaction)
     {
         parent::__construct($eventName);
 
         $this->composer = $composer;
         $this->io = $io;
         $this->devMode = $devMode;
-        $this->repositorySet = $repositorySet;
-        $this->pool = $pool;
-        $this->request = $request;
-        $this->policy = $policy;
+        $this->executeOperations = $executeOperations;
         $this->transaction = $transaction;
     }
 
@@ -120,35 +94,11 @@ class InstallerEvent extends Event
     }
 
     /**
-     * @return PolicyInterface
+     * @return bool
      */
-    public function getPolicy()
+    public function isExecutingOperations()
     {
-        return $this->policy;
-    }
-
-    /**
-     * @return RepositorySet
-     */
-    public function getRepositorySet()
-    {
-        return $this->repositorySet;
-    }
-
-    /**
-     * @return Pool
-     */
-    public function getPool()
-    {
-        return $this->pool;
-    }
-
-    /**
-     * @return Request
-     */
-    public function getRequest()
-    {
-        return $this->request;
+        return $this->executeOperations;
     }
 
     /**
diff --git a/src/Composer/Installer/InstallerEvents.php b/src/Composer/Installer/InstallerEvents.php
index e05c92587..f75b8bdd4 100644
--- a/src/Composer/Installer/InstallerEvents.php
+++ b/src/Composer/Installer/InstallerEvents.php
@@ -12,32 +12,15 @@
 
 namespace Composer\Installer;
 
-/**
- * The Installer Events.
- *
- * @author François Pluchino <francois.pluchino@gmail.com>
- */
 class InstallerEvents
 {
     /**
-     * The PRE_DEPENDENCIES_SOLVING event occurs as a installer begins
-     * resolve operations.
+     * The PRE_OPERATIONS_EXEC event occurs before the lock file gets
+     * installed and operations are executed.
      *
-     * The event listener method receives a
-     * Composer\Installer\InstallerEvent instance.
+     * The event listener method receives an Composer\Installer\InstallerEvent instance.
      *
      * @var string
      */
-    const PRE_DEPENDENCIES_SOLVING = 'pre-dependencies-solving';
-
-    /**
-     * The POST_DEPENDENCIES_SOLVING event occurs as a installer after
-     * resolve operations.
-     *
-     * The event listener method receives a
-     * Composer\Installer\InstallerEvent instance.
-     *
-     * @var string
-     */
-    const POST_DEPENDENCIES_SOLVING = 'post-dependencies-solving';
+    const PRE_OPERATIONS_EXEC = 'pre-operations-exec';
 }
diff --git a/tests/Composer/Test/EventDispatcher/EventDispatcherTest.php b/tests/Composer/Test/EventDispatcher/EventDispatcherTest.php
index 65a5ae62f..c038681da 100644
--- a/tests/Composer/Test/EventDispatcher/EventDispatcherTest.php
+++ b/tests/Composer/Test/EventDispatcher/EventDispatcherTest.php
@@ -565,14 +565,9 @@ class EventDispatcherTest extends TestCase
             ->method('getListeners')
             ->will($this->returnValue(array()));
 
-        $policy = $this->getMockBuilder('Composer\DependencyResolver\PolicyInterface')->getMock();
-        $repositorySet = $this->getMockBuilder('Composer\Repository\RepositorySet')->disableOriginalConstructor()->getMock();
-        $pool = $this->getMockBuilder('Composer\DependencyResolver\Pool')->disableOriginalConstructor()->getMock();
         $transaction = $this->getMockBuilder('Composer\DependencyResolver\LockTransaction')->disableOriginalConstructor()->getMock();
-        $request = $this->getMockBuilder('Composer\DependencyResolver\Request')->disableOriginalConstructor()->getMock();
 
-        $dispatcher->dispatchInstallerEvent(InstallerEvents::PRE_DEPENDENCIES_SOLVING, true, $repositorySet, $pool, $request, $policy);
-        $dispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, true, $repositorySet, $pool, $request, $policy, $transaction);
+        $dispatcher->dispatchInstallerEvent(InstallerEvents::PRE_OPERATIONS_EXEC, true, true, $transaction);
     }
 
     public static function call()
diff --git a/tests/Composer/Test/Installer/InstallerEventTest.php b/tests/Composer/Test/Installer/InstallerEventTest.php
index 52c7baa96..6c0689844 100644
--- a/tests/Composer/Test/Installer/InstallerEventTest.php
+++ b/tests/Composer/Test/Installer/InstallerEventTest.php
@@ -21,21 +21,14 @@ class InstallerEventTest extends TestCase
     {
         $composer = $this->getMockBuilder('Composer\Composer')->getMock();
         $io = $this->getMockBuilder('Composer\IO\IOInterface')->getMock();
-        $policy = $this->getMockBuilder('Composer\DependencyResolver\PolicyInterface')->getMock();
-        $repositorySet = $this->getMockBuilder('Composer\Repository\RepositorySet')->disableOriginalConstructor()->getMock();
-        $pool = $this->getMockBuilder('Composer\DependencyResolver\Pool')->disableOriginalConstructor()->getMock();
         $transaction = $this->getMockBuilder('Composer\DependencyResolver\LockTransaction')->disableOriginalConstructor()->getMock();
-        $request = $this->getMockBuilder('Composer\DependencyResolver\Request')->disableOriginalConstructor()->getMock();
-        $event = new InstallerEvent('EVENT_NAME', $composer, $io, true, $repositorySet, $pool, $request, $policy, $transaction);
+        $event = new InstallerEvent('EVENT_NAME', $composer, $io, true, true, $transaction);
 
         $this->assertSame('EVENT_NAME', $event->getName());
         $this->assertInstanceOf('Composer\Composer', $event->getComposer());
         $this->assertInstanceOf('Composer\IO\IOInterface', $event->getIO());
         $this->assertTrue($event->isDevMode());
-        $this->assertInstanceOf('Composer\DependencyResolver\PolicyInterface', $event->getPolicy());
-        $this->assertInstanceOf('Composer\Repository\RepositorySet', $event->getRepositorySet());
-        $this->assertInstanceOf('Composer\DependencyResolver\Pool', $event->getPool());
-        $this->assertInstanceOf('Composer\DependencyResolver\Request', $event->getRequest());
+        $this->assertTrue($event->isExecutingOperations());
         $this->assertInstanceOf('Composer\DependencyResolver\Transaction', $event->getTransaction());
     }
 }