Merge pull request #7946 from naderman/fix-abs-literal

Fix solver problem exceptions with unexpected contradictory "Conclusions"

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;

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)
+