Merge branch '1.8'

* 1.8:
  Fix solver problem exceptions with unexpected contradictory "Conclusions"
  Also load config into IO if not freshly created
  Only load configuration into IO if IO is available
  Fix defaultRepos fallback does not use auth config

src/Composer/DependencyResolver/Decisions.php

@@ -196,4 +196,16 @@ class Decisions implements \Iterator, \Countable
             $this->decisionMap[$packageId] = -$level;
         }
     }
+
+    public function __toString()
+    {
+        $decisionMap = $this->decisionMap;
+        ksort($decisionMap);
+        $str = '[';
+        foreach ($decisionMap as $packageId => $level) {
+            $str .= $packageId.':'.$level.',';
+        }
+        $str .= ']';
+        return $str;
+    }
 }

src/Composer/DependencyResolver/Solver.php

@@ -470,7 +470,7 @@ class Solver
                 unset($seen[abs($literal)]);
 
                 if ($num && 0 === --$num) {
-                    $learnedLiterals[0] = -abs($literal);
+                    $learnedLiterals[0] = -$literal;
 
                     if (!$l1num) {
                         break 2;

src/Composer/Repository/RepositoryFactory.php

@@ -94,6 +94,9 @@ class RepositoryFactory
         if (!$config) {
             $config = Factory::createConfig($io);
         }
+        if ($io) {
+            $io->loadConfiguration($config);
+        }
         if (!$rm) {
             if (!$io) {
                 throw new \InvalidArgumentException('This function requires either an IOInterface or a RepositoryManager');

tests/Composer/Test/DependencyResolver/SolverTest.php

@@ -838,6 +838,70 @@ class SolverTest extends TestCase
         ));
     }
 
+    /**
+     * Tests for a bug introduced in commit 451bab1c2cd58e05af6e21639b829408ad023463 Solver.php line 554/523
+     *
+     * Every package and link in this test matters, only a combination this complex will run into the situation in which
+     * a negatively decided literal will need to be learned inverted as a positive assertion.
+     *
+     * In particular in this case the goal is to first have the solver decide X 2.0 should not be installed to later
+     * decide to learn that X 2.0 must be installed and revert decisions to retry solving with this new assumption.
+     */
+    public function testLearnPositiveLiteral()
+    {
+        $this->repo->addPackage($packageA = $this->getPackage('A', '1.0'));
+        $this->repo->addPackage($packageB = $this->getPackage('B', '1.0'));
+        $this->repo->addPackage($packageC1 = $this->getPackage('C', '1.0'));
+        $this->repo->addPackage($packageC2 = $this->getPackage('C', '2.0'));
+        $this->repo->addPackage($packageD = $this->getPackage('D', '1.0'));
+        $this->repo->addPackage($packageE = $this->getPackage('E', '1.0'));
+        $this->repo->addPackage($packageF1 = $this->getPackage('F', '1.0'));
+        $this->repo->addPackage($packageF2 = $this->getPackage('F', '2.0'));
+        $this->repo->addPackage($packageG1 = $this->getPackage('G', '1.0'));
+        $this->repo->addPackage($packageG2 = $this->getPackage('G', '2.0'));
+        $this->repo->addPackage($packageG3 = $this->getPackage('G', '3.0'));
+
+        $packageA->setRequires(array(
+            'b' => new Link('A', 'B', $this->getVersionConstraint('==', '1.0'), 'requires'),
+            'c' => new Link('A', 'C', $this->getVersionConstraint('>=', '1.0'), 'requires'),
+            'd' => new Link('A', 'D', $this->getVersionConstraint('==', '1.0'), 'requires'),
+        ));
+
+        $packageB->setRequires(array(
+            'e' => new Link('B', 'E', $this->getVersionConstraint('==', '1.0'), 'requires'),
+        ));
+
+        $packageC1->setRequires(array(
+            'f' => new Link('C', 'F', $this->getVersionConstraint('==', '1.0'), 'requires'),
+        ));
+        $packageC2->setRequires(array(
+            'f' => new Link('C', 'F', $this->getVersionConstraint('==', '1.0'), 'requires'),
+            'g' => new Link('C', 'G', $this->getVersionConstraint('>=', '1.0'), 'requires'),
+        ));
+
+        $packageD->setRequires(array(
+            'f' => new Link('D', 'F', $this->getVersionConstraint('>=', '1.0'), 'requires'),
+        ));
+
+        $packageE->setRequires(array(
+            'g' => new Link('E', 'G', $this->getVersionConstraint('<=', '2.0'), 'requires'),
+        ));
+
+        $this->reposComplete();
+
+        $this->request->install('A');
+
+        $this->checkSolverResult(array(
+            array('job' => 'install', 'package' => $packageF1),
+            array('job' => 'install', 'package' => $packageD),
+            array('job' => 'install', 'package' => $packageG2),
+            array('job' => 'install', 'package' => $packageC2),
+            array('job' => 'install', 'package' => $packageE),
+            array('job' => 'install', 'package' => $packageB),
+            array('job' => 'install', 'package' => $packageA),
+        ));
+    }
+
     protected function reposComplete()
     {
         $this->pool->addRepository($this->repoInstalled);

tests/Composer/Test/Fixtures/installer/update-requiring-decision-reverts-and-learning-positive-literals.test

@@ -0,0 +1,100 @@
+--TEST--
+Update a project which requires decision reverts and learning a positive literal to arrive at a correct solution.
+
+Tests for solver regression in commit 451bab1c2cd58e05af6e21639b829408ad023463. See also SolverTest testLearnPositiveLiteral
+--COMPOSER--
+{
+    "repositories": [
+        {
+            "type": "package",
+            "package": [
+                {
+                    "name": "spryker-feature/product",
+                    "require": {
+                        "spryker-feature/spryker-core": "1.0.0",
+                        "spryker-shop/product-search-widget": ">=1.0.0",
+                        "spryker/product-category-filter-gui": "1.0.0"
+                    },
+                    "version": "1.0.0"
+                },
+                {
+                    "name": "spryker-feature/spryker-core",
+                    "version": "1.0.0",
+                    "require": {
+                        "spryker/store": "1.0.0"
+                    }
+                },
+                {
+                    "name": "spryker/store",
+                    "version": "1.0.0",
+                    "require": {
+                        "spryker/kernel": "<=2.0.0"
+                    }
+                },
+                {
+                    "name": "spryker-shop/product-search-widget",
+                    "version": "1.0.0",
+                    "require": {
+                        "spryker/catalog": "1.0.0"
+                    }
+                },
+                {
+                    "name": "spryker-shop/product-search-widget",
+                    "version": "2.0.0",
+                    "require": {
+                        "spryker/catalog": "1.0.0",
+                        "spryker/kernel": ">=1.0.0"
+                    }
+                },
+                {
+                    "name": "spryker/product-category-filter-gui",
+                    "version": "1.0.0",
+                    "require": {
+                        "spryker/catalog": ">=1.0.0"
+                    }
+                },
+                {
+                    "name": "spryker/catalog",
+                    "version": "1.0.0",
+                    "require": { }
+                },
+                {
+                    "name": "spryker/catalog",
+                    "version": "2.0.0",
+                    "require": { }
+                },
+
+                {
+                    "name": "spryker/kernel",
+                    "version": "1.0.0",
+                    "require": { }
+                },
+                {
+                    "name": "spryker/kernel",
+                    "version": "2.0.0",
+                    "require": {
+                    }
+                },
+                {
+                    "name": "spryker/kernel",
+                    "version": "3.0.0",
+                    "require": { }
+                }
+            ]
+        }
+    ],
+    "require": {
+        "spryker-feature/product": "1.0.0"
+    }
+}
+--RUN--
+update
+--EXPECT--
+Installing spryker/catalog (1.0.0)
+Installing spryker/product-category-filter-gui (1.0.0)
+Installing spryker/kernel (2.0.0)
+Installing spryker-shop/product-search-widget (2.0.0)
+Installing spryker/store (1.0.0)
+Installing spryker-feature/spryker-core (1.0.0)
+Installing spryker-feature/product (1.0.0)
+