Add '!=' handling to VersionConstraint::matchSpecific

src/Composer/Package/LinkConstraint/VersionConstraint.php

@@ -36,6 +36,10 @@ class VersionConstraint extends SpecificConstraint
             $operator = '==';
         }
 
+        if ('<>' === $operator) {
+            $operator = '!=';
+        }
+
         $this->operator = $operator;
         $this->version = $version;
     }
@@ -49,6 +53,18 @@ class VersionConstraint extends SpecificConstraint
         $noEqualOp = str_replace('=', '', $this->operator);
         $providerNoEqualOp = str_replace('=', '', $provider->operator);
 
+        $isEqualOp = '==' === $this->operator;
+        $isNonEqualOp = '!=' === $this->operator;
+        $isProviderEqualOp = '==' === $provider->operator;
+        $isProviderNonEqualOp = '!=' === $provider->operator;
+
+        // '!=' operator is match when other operator is not '==' operator or version is not match
+        // these kinds of comparisons always have a solution
+        if ($isNonEqualOp || $isProviderNonEqualOp) {
+            return !$isEqualOp && !$isProviderEqualOp
+                || version_compare($provider->version, $this->version, '!=');
+        }
+
         // an example for the condition is <= 2.0 & < 1.0
         // these kinds of comparisons always have a solution
         if ($this->operator != '==' && $noEqualOp == $providerNoEqualOp) {

tests/Composer/Test/Package/LinkConstraint/VersionConstraintTest.php

@@ -27,6 +27,12 @@ class VersionConstraintTest extends \PHPUnit_Framework_TestCase
             array('<=', '2', '>=', '1'),
             array('>=', '1', '<=', '2'),
             array('==', '2', '>=', '2'),
+            array('!=', '1', '!=', '1'),
+            array('!=', '1', '==', '2'),
+            array('!=', '1', '<',  '1'),
+            array('!=', '1', '<=', '1'),
+            array('!=', '1', '>',  '1'),
+            array('!=', '1', '>=', '1'),
         );
     }
 
@@ -53,6 +59,8 @@ class VersionConstraintTest extends \PHPUnit_Framework_TestCase
             array('<=', '1', '>=', '2'),
             array('>=', '2', '<=', '1'),
             array('==', '2', '<', '2'),
+            array('!=', '1', '==', '1'),
+            array('==', '1', '!=', '1'),
         );
     }