Add extra logging before and after SAT solving

src/Composer/DependencyResolver/Solver.php

@@ -12,6 +12,7 @@
 
 namespace Composer\DependencyResolver;
 
+use Composer\IO\IOInterface;
 use Composer\Repository\RepositoryInterface;
 use Composer\Repository\PlatformRepository;
 
@@ -56,13 +57,18 @@ class Solver
     /** @var array */
     protected $learnedWhy = array();
 
+    /** @var IOInterface */
+    protected $io;
+
     /**
      * @param PolicyInterface     $policy
      * @param Pool                $pool
      * @param RepositoryInterface $installed
+     * @param IOInterface         $io
      */
-    public function __construct(PolicyInterface $policy, Pool $pool, RepositoryInterface $installed)
+    public function __construct(PolicyInterface $policy, Pool $pool, RepositoryInterface $installed, IOInterface $io)
     {
+        $this->io = $io;
         $this->policy = $policy;
         $this->pool = $pool;
         $this->installed = $installed;
@@ -217,7 +223,10 @@ class Solver
         /* make decisions based on job/update assertions */
         $this->makeAssertionRuleDecisions();
 
+        $this->io->writeError('Resolving dependencies through SAT', true, IOInterface::DEBUG);
+        $before = microtime(true);
         $this->runSat(true);
+        $this->io->writeError(sprintf('Dependency resolution completed in %.3f seconds', microtime(true) - $before), true, IOInterface::VERBOSE);
 
         // decide to remove everything that's installed and undecided
         foreach ($this->installedMap as $packageId => $void) {

src/Composer/Installer.php

@@ -287,7 +287,7 @@ class Installer
                     }
 
                     $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::PRE_DEPENDENCIES_SOLVING, false, $policy, $pool, $installedRepo, $request);
-                    $solver = new Solver($policy, $pool, $installedRepo);
+                    $solver = new Solver($policy, $pool, $installedRepo, $this->io);
                     $ops = $solver->solve($request, $this->ignorePlatformReqs);
                     $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, false, $policy, $pool, $installedRepo, $request, $ops);
                     foreach ($ops as $op) {
@@ -493,7 +493,7 @@ class Installer
 
         // solve dependencies
         $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::PRE_DEPENDENCIES_SOLVING, $this->devMode, $policy, $pool, $installedRepo, $request);
-        $solver = new Solver($policy, $pool, $installedRepo);
+        $solver = new Solver($policy, $pool, $installedRepo, $this->io);
         try {
             $operations = $solver->solve($request, $this->ignorePlatformReqs);
             $this->eventDispatcher->dispatchInstallerEvent(InstallerEvents::POST_DEPENDENCIES_SOLVING, $this->devMode, $policy, $pool, $installedRepo, $request, $operations);

tests/Composer/Test/DependencyResolver/SolverTest.php

@@ -12,6 +12,7 @@
 
 namespace Composer\Test\DependencyResolver;
 
+use Composer\IO\NullIO;
 use Composer\Repository\ArrayRepository;
 use Composer\DependencyResolver\DefaultPolicy;
 use Composer\DependencyResolver\Pool;
@@ -38,7 +39,7 @@ class SolverTest extends TestCase
 
         $this->request = new Request($this->pool);
         $this->policy = new DefaultPolicy;
-        $this->solver = new Solver($this->policy, $this->pool, $this->repoInstalled);
+        $this->solver = new Solver($this->policy, $this->pool, $this->repoInstalled, new NullIO());
     }
 
     public function testSolverInstallSingle()