Remove disableRules code from Solver, leftover from original C code

This goes back to an input option to install recommended packages, which
would in turn allow removal of these packages if that was needed to
resolve the rest. This was supported in very early versions of Composer
with suggested packages. We later realized this was not useful in the
context of a project based dependency manager with a lock file, so it
was removed but the solver was never cleaned up.

src/Composer/DependencyResolver/Solver.php

@@ -213,7 +213,7 @@ class Solver
 
         $this->io->writeError('Resolving dependencies through SAT', true, IOInterface::DEBUG);
         $before = microtime(true);
-        $this->runSat(true);
+        $this->runSat();
         $this->io->writeError('', true, IOInterface::DEBUG);
         $this->io->writeError(sprintf('Dependency resolution completed in %.3f seconds', microtime(true) - $before), true, IOInterface::VERBOSE);
 
@@ -298,11 +298,10 @@ class Solver
      *
      * @param  int        $level
      * @param  string|int $literal
-     * @param  bool       $disableRules
      * @param  Rule       $rule
      * @return int
      */
-    private function setPropagateLearn($level, $literal, $disableRules, Rule $rule)
+    private function setPropagateLearn($level, $literal, Rule $rule)
     {
         $level++;
 
@@ -316,7 +315,7 @@ class Solver
             }
 
             if ($level == 1) {
-                return $this->analyzeUnsolvable($rule, $disableRules);
+                return $this->analyzeUnsolvable($rule);
             }
 
             // conflict
@@ -353,11 +352,10 @@ class Solver
     /**
      * @param  int   $level
      * @param  array $decisionQueue
-     * @param  bool  $disableRules
      * @param  Rule  $rule
      * @return int
      */
-    private function selectAndInstall($level, array $decisionQueue, $disableRules, Rule $rule)
+    private function selectAndInstall($level, array $decisionQueue, Rule $rule)
     {
         // choose best package to install from decisionQueue
         $literals = $this->policy->selectPreferredPackages($this->pool, $decisionQueue, $rule->getRequiredPackage());
@@ -369,7 +367,7 @@ class Solver
             $this->branches[] = array($literals, $level);
         }
 
-        return $this->setPropagateLearn($level, $selectedLiteral, $disableRules, $rule);
+        return $this->setPropagateLearn($level, $selectedLiteral, $rule);
     }
 
     /**
@@ -515,10 +513,9 @@ class Solver
 
     /**
      * @param  Rule $conflictRule
-     * @param  bool $disableRules
      * @return int
      */
-    private function analyzeUnsolvable(Rule $conflictRule, $disableRules)
+    private function analyzeUnsolvable(Rule $conflictRule)
     {
         $problem = new Problem($this->pool);
         $problem->addRule($conflictRule);
@@ -562,16 +559,6 @@ class Solver
             }
         }
 
-        if ($disableRules) {
-            foreach ($this->problems[count($this->problems) - 1] as $reason) {
-                $this->disableProblem($reason['rule']);
-            }
-
-            $this->resetSolver();
-
-            return 1;
-        }
-
         return 0;
     }
 
@@ -637,10 +624,7 @@ class Solver
         }
     }
 
-    /**
+    private function runSat()
-     * @param bool $disableRules
-     */
-    private function runSat($disableRules = true)
     {
         $this->propagateIndex = 0;
 
@@ -656,10 +640,6 @@ class Solver
 
         $decisionQueue = array();
         $decisionSupplementQueue = array();
-        /**
-         * @todo this makes $disableRules always false; determine the rationale and possibly remove dead code?
-         */
-        $disableRules = false;
 
         $level = 1;
         $systemLevel = $level + 1;
@@ -669,7 +649,7 @@ class Solver
             if (1 === $level) {
                 $conflictRule = $this->propagate($level);
                 if (null !== $conflictRule) {
-                    if ($this->analyzeUnsolvable($conflictRule, $disableRules)) {
+                    if ($this->analyzeUnsolvable($conflictRule)) {
                         continue;
                     }
 
@@ -710,7 +690,7 @@ class Solver
 
                         if ($noneSatisfied && count($decisionQueue)) {
                             $oLevel = $level;
-                            $level = $this->selectAndInstall($level, $decisionQueue, $disableRules, $rule);
+                            $level = $this->selectAndInstall($level, $decisionQueue, $rule);
 
                             if (0 === $level) {
                                 return;
@@ -786,7 +766,7 @@ class Solver
                     continue;
                 }
 
-                $level = $this->selectAndInstall($level, $decisionQueue, $disableRules, $rule);
+                $level = $this->selectAndInstall($level, $decisionQueue, $rule);
 
                 if (0 === $level) {
                     return;
@@ -829,7 +809,7 @@ class Solver
 
                     $why = $this->decisions->lastReason();
 
-                    $level = $this->setPropagateLearn($level, $lastLiteral, $disableRules, $why);
+                    $level = $this->setPropagateLearn($level, $lastLiteral, $why);
 
                     if ($level == 0) {
                         return;