diff --git a/src/Composer/Command/InitCommand.php b/src/Composer/Command/InitCommand.php
index f1d8e6f91..5a2568886 100644
--- a/src/Composer/Command/InitCommand.php
+++ b/src/Composer/Command/InitCommand.php
@@ -349,7 +349,7 @@ EOT
         }
 
         $author = $io->askAndValidate(
-            'Author [<comment>'.$author.'</comment>, n to skip]: ',
+            'Author ['.(is_string($author) ? '<comment>'.$author.'</comment>, ' : '') . 'n to skip]: ',
             function ($value) use ($author) {
                 if ($value === 'n' || $value === 'no') {
                     return;
@@ -357,6 +357,10 @@ EOT
                 $value = $value ?: $author;
                 $author = $this->parseAuthorString($value);
 
+                if ($author['email'] === null) {
+                    return $author['name'];
+                }
+
                 return sprintf('%s <%s>', $author['name'], $author['email']);
             },
             null,
@@ -470,33 +474,41 @@ EOT
     /**
      * @private
      * @param  string $author
-     * @return array{name: string, email: string}
+     * @return array{name: string, email: string|null}
      */
     public function parseAuthorString($author)
     {
-        if (Preg::isMatch('/^(?P<name>[- .,\p{L}\p{N}\p{Mn}\'’"()]+) <(?P<email>.+?)>$/u', $author, $match)) {
-            if ($this->isValidEmail($match['email'])) {
-                return array(
-                    'name' => trim($match['name']),
-                    'email' => $match['email'],
-                );
+        if (Preg::isMatch('/^(?P<name>[- .,\p{L}\p{N}\p{Mn}\'’"()]+)(?:\s+<(?P<email>.+?)>)?$/u', $author, $match)) {
+            $hasEmail = isset($match['email']) && '' !== $match['email'];
+            if ($hasEmail && !$this->isValidEmail($match['email'])) {
+                throw new \InvalidArgumentException('Invalid email "'.$match['email'].'"');
             }
+
+            return array(
+                'name' => trim($match['name']),
+                'email' => $hasEmail ? $match['email'] : null,
+            );
         }
 
         throw new \InvalidArgumentException(
-            'Invalid author string.  Must be in the format: '.
-            'John Smith <john@example.com>'
+            'Invalid author string.  Must be in the formats: '.
+            'Jane Doe or John Smith <john@example.com>'
         );
     }
 
     /**
      * @param string $author
      *
-     * @return array<int, array{name: string, email: string}>
+     * @return array<int, array{name: string, email?: string}>
      */
     protected function formatAuthors($author)
     {
-        return array($this->parseAuthorString($author));
+        $author = $this->parseAuthorString($author);
+        if (null === $author['email']) {
+            unset($author['email']);
+        }
+
+        return array($author);
     }
 
     /**
diff --git a/src/Composer/Command/LicensesCommand.php b/src/Composer/Command/LicensesCommand.php
index 5c02e9d72..5a9bfa16b 100644
--- a/src/Composer/Command/LicensesCommand.php
+++ b/src/Composer/Command/LicensesCommand.php
@@ -86,7 +86,7 @@ EOT
                 $tableStyle = $table->getStyle();
                 $tableStyle->setVerticalBorderChars('');
                 $tableStyle->setCellRowContentFormat('%s  ');
-                $table->setHeaders(array('Name', 'Version', 'License'));
+                $table->setHeaders(array('Name', 'Version', 'Licenses'));
                 foreach ($packages as $package) {
                     $link = PackageInfo::getViewSourceOrHomepageUrl($package);
                     if ($link !== null) {
@@ -124,12 +124,16 @@ EOT
             case 'summary':
                 $usedLicenses = array();
                 foreach ($packages as $package) {
-                    $license = $package instanceof CompletePackageInterface ? $package->getLicense() : array();
-                    $licenseName = $license[0];
-                    if (!isset($usedLicenses[$licenseName])) {
-                        $usedLicenses[$licenseName] = 0;
+                    $licenses = $package instanceof CompletePackageInterface ? $package->getLicense() : array();
+                    if (count($licenses) === 0) {
+                        $licenses[] = 'none';
+                    }
+                    foreach ($licenses as $licenseName) {
+                        if (!isset($usedLicenses[$licenseName])) {
+                            $usedLicenses[$licenseName] = 0;
+                        }
+                        $usedLicenses[$licenseName]++;
                     }
-                    $usedLicenses[$licenseName]++;
                 }
 
                 // Sort licenses so that the most used license will appear first
diff --git a/src/Composer/Repository/Vcs/GitBitbucketDriver.php b/src/Composer/Repository/Vcs/GitBitbucketDriver.php
index 694204899..dd4033991 100644
--- a/src/Composer/Repository/Vcs/GitBitbucketDriver.php
+++ b/src/Composer/Repository/Vcs/GitBitbucketDriver.php
@@ -61,7 +61,10 @@ class GitBitbucketDriver extends VcsDriver
      */
     public function initialize()
     {
-        Preg::match('#^https?://bitbucket\.org/([^/]+)/([^/]+?)(\.git|/?)?$#i', $this->url, $match);
+        if (!Preg::isMatch('#^https?://bitbucket\.org/([^/]+)/([^/]+?)(\.git|/?)?$#i', $this->url, $match)) {
+            throw new \InvalidArgumentException(sprintf('The Bitbucket repository URL %s is invalid. It must be the HTTPS URL of a Bitbucket repository.', $this->url));
+        }
+
         $this->owner = $match[1];
         $this->repository = $match[2];
         $this->originUrl = 'bitbucket.org';
diff --git a/src/Composer/Repository/Vcs/GitHubDriver.php b/src/Composer/Repository/Vcs/GitHubDriver.php
index e95492a66..33d7e8cd3 100644
--- a/src/Composer/Repository/Vcs/GitHubDriver.php
+++ b/src/Composer/Repository/Vcs/GitHubDriver.php
@@ -59,7 +59,10 @@ class GitHubDriver extends VcsDriver
      */
     public function initialize()
     {
-        Preg::match('#^(?:(?:https?|git)://([^/]+)/|git@([^:]+):/?)([^/]+)/(.+?)(?:\.git|/)?$#', $this->url, $match);
+        if (!Preg::isMatch('#^(?:(?:https?|git)://([^/]+)/|git@([^:]+):/?)([^/]+)/(.+?)(?:\.git|/)?$#', $this->url, $match)) {
+            throw new \InvalidArgumentException(sprintf('The GitHub repository URL %s is invalid.', $this->url));
+        }
+
         $this->owner = $match[3];
         $this->repository = $match[4];
         $this->originUrl = strtolower(!empty($match[1]) ? $match[1] : $match[2]);
diff --git a/src/Composer/Repository/Vcs/GitLabDriver.php b/src/Composer/Repository/Vcs/GitLabDriver.php
index 3c45b4e73..2e7d36cc2 100644
--- a/src/Composer/Repository/Vcs/GitLabDriver.php
+++ b/src/Composer/Repository/Vcs/GitLabDriver.php
@@ -94,7 +94,7 @@ class GitLabDriver extends VcsDriver
     public function initialize()
     {
         if (!Preg::isMatch(self::URL_REGEX, $this->url, $match)) {
-            throw new \InvalidArgumentException('The URL provided is invalid. It must be the HTTP URL of a GitLab project.');
+            throw new \InvalidArgumentException(sprintf('The GitLab repository URL %s is invalid. It must be the HTTP URL of a GitLab project.', $this->url));
         }
 
         $guessedDomain = !empty($match['domain']) ? $match['domain'] : $match['domain2'];
diff --git a/tests/Composer/Test/Command/InitCommandTest.php b/tests/Composer/Test/Command/InitCommandTest.php
index 7cb6fe94c..22950158e 100644
--- a/tests/Composer/Test/Command/InitCommandTest.php
+++ b/tests/Composer/Test/Command/InitCommandTest.php
@@ -25,6 +25,14 @@ class InitCommandTest extends TestCase
         $this->assertEquals('john@example.com', $author['email']);
     }
 
+    public function testParseValidAuthorStringWithoutEmail()
+    {
+        $command = new InitCommand;
+        $author = $command->parseAuthorString('John Smith');
+        $this->assertEquals('John Smith', $author['name']);
+        $this->assertNull($author['email']);
+    }
+
     public function testParseValidUtf8AuthorString()
     {
         $command = new InitCommand;
diff --git a/tests/Composer/Test/Repository/Vcs/GitBitbucketDriverTest.php b/tests/Composer/Test/Repository/Vcs/GitBitbucketDriverTest.php
index a8ee520f0..66de8b7eb 100644
--- a/tests/Composer/Test/Repository/Vcs/GitBitbucketDriverTest.php
+++ b/tests/Composer/Test/Repository/Vcs/GitBitbucketDriverTest.php
@@ -217,6 +217,14 @@ class GitBitbucketDriverTest extends TestCase
         );
     }
 
+    public function testInitializeInvalidRepositoryUrl()
+    {
+        $this->expectException('\InvalidArgumentException');
+
+        $driver = $this->getDriver(array('url' => 'https://bitbucket.org/acme'));
+        $driver->initialize();
+    }
+
     public function testSupports()
     {
         $this->assertTrue(
diff --git a/tests/Composer/Test/Repository/Vcs/GitHubDriverTest.php b/tests/Composer/Test/Repository/Vcs/GitHubDriverTest.php
index 6ec9c25dc..ad7d15896 100644
--- a/tests/Composer/Test/Repository/Vcs/GitHubDriverTest.php
+++ b/tests/Composer/Test/Repository/Vcs/GitHubDriverTest.php
@@ -14,11 +14,11 @@ namespace Composer\Test\Repository\Vcs;
 
 use Composer\Downloader\TransportException;
 use Composer\Repository\Vcs\GitHubDriver;
+use Composer\Test\Mock\ProcessExecutorMock;
 use Composer\Test\TestCase;
 use Composer\Util\Filesystem;
-use Composer\Util\Http\Response;
-use Composer\Test\Mock\ProcessExecutorMock;
 use Composer\Config;
+use Composer\Util\Http\Response;
 use Composer\Util\ProcessExecutor;
 
 class GitHubDriverTest extends TestCase
@@ -306,6 +306,50 @@ class GitHubDriverTest extends TestCase
         $this->assertEquals($sha, $source['reference']);
     }
 
+    /**
+     * @return void
+     */
+    public function initializeInvalidReoUrl()
+    {
+        $this->expectException('\InvalidArgumentException');
+
+        $repoConfig = array(
+            'url' => 'https://github.com/acme',
+        );
+
+        $io = $this->getMockBuilder('Composer\IO\IOInterface')->getMock();
+        $httpDownloader = $this->getMockBuilder('Composer\Util\HttpDownloader')
+            ->setConstructorArgs(array($io, $this->config))
+            ->getMock();
+
+        $gitHubDriver = new GitHubDriver($repoConfig, $io, $this->config, $httpDownloader, new ProcessExecutorMock);
+        $gitHubDriver->initialize();
+    }
+
+    /**
+     * @dataProvider supportsProvider
+     * @param bool $expected
+     * @param string $repoUrl
+     */
+    public function testSupports($expected, $repoUrl)
+    {
+        $io = $this->getMockBuilder('Composer\IO\IOInterface')->getMock();
+
+        $this->assertSame($expected, GitHubDriver::supports($io, $this->config, $repoUrl));
+    }
+
+    /**
+     * @return list<array{bool, string}>
+     */
+    public function supportsProvider()
+    {
+        return array(
+            array(false, 'https://github.com/acme'),
+            array(true, 'https://github.com/acme/repository'),
+            array(true, 'git@github.com:acme/repository.git'),
+        );
+    }
+
     /**
      * @param string|object $object
      * @param string        $attribute