Add key fingerprints for easier comparison and debugging via diagnose

src/Composer/Command/DiagnoseCommand.php

@@ -22,6 +22,7 @@ use Composer\Util\ConfigValidator;
 use Composer\Util\ProcessExecutor;
 use Composer\Util\RemoteFilesystem;
 use Composer\Util\StreamContextFactory;
+use Composer\Util\Keys;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Output\OutputInterface;
 
@@ -133,6 +134,9 @@ EOT
         $io->write('Checking disk free space: ', false);
         $this->outputResult($this->checkDiskSpace($config));
 
+        $io->write('Checking pubkeys: ', false);
+        $this->outputResult($this->checkPubKeys($config));
+
         $io->write('Checking composer version: ', false);
         $this->outputResult($this->checkVersion());
 
@@ -327,6 +331,35 @@ EOT
         return true;
     }
 
+    private function checkPubKeys($config)
+    {
+        $home = $config->get('home');
+        $errors = [];
+        $io = $this->getIO();
+
+        if (file_exists($home.'/keys.tags.pub') && file_exists($home.'/keys.dev.pub')) {
+            $io->write('');
+        }
+
+        if (file_exists($home.'/keys.tags.pub')) {
+            $io->write('Tags Public Key Fingerprint: ' . Keys::fingerprint($home.'/keys.tags.pub'));
+        } else {
+            $errors[] = '<error>Missing pubkey for tags verification</error>';
+        }
+
+        if (file_exists($home.'/keys.dev.pub')) {
+            $io->write('Dev Public Key Fingerprint: ' . Keys::fingerprint($home.'/keys.dev.pub'));
+        } else {
+            $errors[] = '<error>Missing pubkey for dev verification</error>';
+        }
+
+        if ($errors) {
+            $errors[] = '<error>Run composer self-update --update-keys to set them up</error>';
+        }
+
+        return $errors ?: true;
+    }
+
     private function checkVersion()
     {
         $protocol = extension_loaded('openssl') ? 'https' : 'http';

src/Composer/Command/SelfUpdateCommand.php

@@ -16,6 +16,7 @@ use Composer\Composer;
 use Composer\Factory;
 use Composer\Config;
 use Composer\Util\Filesystem;
+use Composer\Util\Keys;
 use Composer\IO\IOInterface;
 use Composer\Util\RemoteFilesystem;
 use Composer\Downloader\FilesystemException;
@@ -220,7 +221,8 @@ EOT
                 }
             }
         }
-        file_put_contents($config->get('home').'/keys.dev.pub', $match[0]);
+        file_put_contents($keyPath = $config->get('home').'/keys.dev.pub', $match[0]);
+        $io->write('Stored key with fingerprint: ' . Keys::fingerprint($keyPath));
 
         $tagsKey = '';
         while (!preg_match('{(-----BEGIN PUBLIC KEY-----.+?-----END PUBLIC KEY-----)}s', $tagsKey, $match)) {
@@ -232,7 +234,8 @@ EOT
                 }
             }
         }
-        file_put_contents($config->get('home').'/keys.tags.pub', $match[0]);
+        file_put_contents($keyPath = $config->get('home').'/keys.tags.pub', $match[0]);
+        $io->write('Stored key with fingerprint: ' . Keys::fingerprint($keyPath));
 
         $io->write('Public keys stored in '.$config->get('home'));
     }