symfony
diff --git a/‎src/Symfony/Component/Process/Process.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Process/Process.php
+29-3Lines changed: 29 additions & 3 deletions b/‎src/Symfony/Component/Process/Process.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Process/Process.php
+29-3Lines changed: 29 additions & 3 deletions
diff --git a/‎src/Symfony/Component/Process/Tests/ProcessTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Process/Tests/ProcessTest.php
+28Lines changed: 28 additions & 0 deletions b/‎src/Symfony/Component/Process/Tests/ProcessTest.php
Copy file name to clipboardExpand all lines: src/Symfony/Component/Process/Tests/ProcessTest.php
+28Lines changed: 28 additions & 0 deletions
@@ -258,18 +258,21 @@ public function start(callable $callback = null, array $env = array())
         $this->hasCallback = null !== $callback;
         $descriptors = $this->getDescriptors();
 
+        if ($this->env) {
+            $env += $this->env;
+        }
+
         if (is_array($commandline = $this->commandline)) {
             $commandline = implode(' ', array_map(array($this, 'escapeArgument'), $commandline));
 
             if ('\\' !== DIRECTORY_SEPARATOR) {
                 // exec is mandatory to deal with sending a signal to the process
                 $commandline = 'exec '.$commandline;
             }
+        } else {
+            $commandline = $this->replacePlaceholders($commandline, $env);
         }
 
-        if ($this->env) {
-            $env += $this->env;
-        }
         $env += $this->getDefaultEnv();
 
         $options = array('suppress_errors' => true);
@@ -1549,6 +1552,29 @@ private function escapeArgument(string $argument): string
         return '"'.str_replace(array('"', '^', '%', '!', "\n"), array('""', '"^^"', '"^%"', '"^!"', '!LF!'), $argument).'"';
     }
 
+    private function replacePlaceholders(string $commandline, array $env)
+    {
+        $pattern = '\\' === DIRECTORY_SEPARATOR ? '!%s!' : '${%s}';
+
+        return preg_replace_callback('/\{\{ ?([_a-zA-Z0-9]++) ?\}\}/', function ($m) use ($pattern, $commandline, $env) {
+            if (!isset($env[$m[1]]) || false === $env[$m[1]]) {
+                foreach ($env as $k => $v) {
+                    if (false === $v) {
+                        unset($env[$k]);
+                    }
+                }
+                if (!$env) {
+                    throw new InvalidArgumentException(sprintf('Invalid command line "%s": no values provided for any placeholders.', $commandline));
+                }
+                $env = implode('", "', array_keys($env));
+
+                throw new InvalidArgumentException(sprintf('Invalid command line "%s": no value provided for placeholder "%s", did you mean "%s"?', $commandline, $m[1], $env));
+            }
+
+            return sprintf($pattern, $m[1]);
+        }, $commandline);
+    }
+
     private function getDefaultEnv()
     {
         $env = array();
 
@@ -1474,6 +1474,34 @@ public function provideEscapeArgument()
         yield array('éÉèÈàÀöä');
     }
 
+    public function testPreparedCommand()
+    {
+        $p = new Process('echo {{ abc }}DEF');
+        $p->run(null, array('abc' => 'ABC'));
+
+        $this->assertSame('ABCDEF', rtrim($p->getOutput()));
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Process\Exception\InvalidArgumentException
+     * @expectedExceptionMessage Invalid command line "echo {{ abc }}": no value provided for placeholder "abc", did you mean "bcd"?
+     */
+    public function testPreparedCommandWithMissingValue()
+    {
+        $p = new Process('echo {{ abc }}');
+        $p->run(null, array('bcd' => 'BCD'));
+    }
+
+    /**
+     * @expectedException \Symfony\Component\Process\Exception\InvalidArgumentException
+     * @expectedExceptionMessage Invalid command line "echo {{ abc }}": no values provided for any placeholders.
+     */
+    public function testPreparedCommandWithNoValues()
+    {
+        $p = new Process('echo {{ abc }}');
+        $p->run();
+    }
+
     public function testEnvArgument()
     {
         $env = array('FOO' => 'Foo', 'BAR' => 'Bar');