diff --git a/doc/05-repositories.md b/doc/05-repositories.md
index c551ff9e6..22f64c79e 100644
--- a/doc/05-repositories.md
+++ b/doc/05-repositories.md
@@ -658,6 +658,17 @@ the branch or tag that is currently checked out. Otherwise, the version should
 be explicitly defined in the package's `composer.json` file. If the version
 cannot be resolved by these means, it is assumed to be `dev-master`.
 
+When the version cannot be inferred from the local VCS repository, you should use
+the special `branch-version` entry under `extra` instead of `version`:
+
+```json
+{
+    "extra": {
+        "branch-version": "4.2-dev"
+    }
+}
+```
+
 The local package will be symlinked if possible, in which case the output in
 the console will read `Symlinking from ../../packages/my-package`. If symlinking
 is _not_ possible the package will be copied. In that case, the console will
diff --git a/src/Composer/Package/Loader/RootPackageLoader.php b/src/Composer/Package/Loader/RootPackageLoader.php
index 32118b113..aa6134735 100644
--- a/src/Composer/Package/Loader/RootPackageLoader.php
+++ b/src/Composer/Package/Loader/RootPackageLoader.php
@@ -81,8 +81,10 @@ class RootPackageLoader extends ArrayLoader
         if (!isset($config['version'])) {
             $commit = null;
 
-            // override with env var if available
-            if (getenv('COMPOSER_ROOT_VERSION')) {
+            if (isset($config['extra']['branch-version'])) {
+                $config['version'] = preg_replace('{(\.x)?(-dev)?$}', '.x-dev', $config['extra']['branch-version']);
+            } elseif (getenv('COMPOSER_ROOT_VERSION')) {
+                // override with env var if available
                 $config['version'] = getenv('COMPOSER_ROOT_VERSION');
             } else {
                 $versionData = $this->versionGuesser->guessVersion($config, $cwd ?: getcwd());
diff --git a/src/Composer/Repository/PathRepository.php b/src/Composer/Repository/PathRepository.php
index a0a6835b8..f9aa4aea0 100644
--- a/src/Composer/Repository/PathRepository.php
+++ b/src/Composer/Repository/PathRepository.php
@@ -165,6 +165,11 @@ class PathRepository extends ArrayRepository implements ConfigurableRepositoryIn
             );
             $package['transport-options'] = $this->options;
 
+            // use the branch-version as the package version if available
+            if (!isset($package['version']) && isset($package['extra']['branch-version'])) {
+                $package['version'] = preg_replace('{(\.x)?(-dev)?$}', '.x-dev', $package['extra']['branch-version']);
+            }
+
             // carry over the root package version if this path repo is in the same git repository as root package
             if (!isset($package['version']) && ($rootVersion = getenv('COMPOSER_ROOT_VERSION'))) {
                 if (
diff --git a/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php b/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php
index 858e95231..f22954a9a 100644
--- a/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php
+++ b/tests/Composer/Test/Package/Loader/RootPackageLoaderTest.php
@@ -201,4 +201,15 @@ class RootPackageLoaderTest extends TestCase
 
         $this->assertEquals("dev-latest-production", $package->getPrettyVersion());
     }
+
+    public function testLoadExtraBranchVersion()
+    {
+        $package = $this->loadPackage(array(
+            'extra' => array(
+                'branch-version' => '1.2',
+            ),
+        ));
+
+        $this->assertEquals('1.2.x-dev', $package->getPrettyVersion());
+    }
 }
diff --git a/tests/Composer/Test/Repository/Fixtures/path/with-branch-version/composer.json b/tests/Composer/Test/Repository/Fixtures/path/with-branch-version/composer.json
new file mode 100644
index 000000000..75545d5f9
--- /dev/null
+++ b/tests/Composer/Test/Repository/Fixtures/path/with-branch-version/composer.json
@@ -0,0 +1,6 @@
+{
+  "name": "test/path-branch-versioned",
+  "extra": {
+    "branch-version": "1.2"
+  }
+}
diff --git a/tests/Composer/Test/Repository/PathRepositoryTest.php b/tests/Composer/Test/Repository/PathRepositoryTest.php
index 159d8cc97..628c3320d 100644
--- a/tests/Composer/Test/Repository/PathRepositoryTest.php
+++ b/tests/Composer/Test/Repository/PathRepositoryTest.php
@@ -72,6 +72,23 @@ class PathRepositoryTest extends TestCase
         $this->assertNotEmpty($packageVersion);
     }
 
+    public function testLoadPackageFromFileSystemWithExtraBranchVersion()
+    {
+        $ioInterface = $this->getMockBuilder('Composer\IO\IOInterface')
+            ->getMock();
+
+        $config = new \Composer\Config();
+        $versionGuesser = null;
+
+        $repositoryUrl = implode(DIRECTORY_SEPARATOR, array(__DIR__, 'Fixtures', 'path', 'with-branch-version'));
+        $repository = new PathRepository(array('url' => $repositoryUrl), $ioInterface, $config);
+        $packages = $repository->getPackages();
+
+        $this->assertEquals(1, $repository->count());
+
+        $this->assertTrue($repository->hasPackage($this->getPackage('test/path-branch-versioned', '1.2.x-dev')));
+    }
+
     public function testLoadPackageFromFileSystemWithWildcard()
     {
         $ioInterface = $this->getMockBuilder('Composer\IO\IOInterface')
@@ -85,7 +102,7 @@ class PathRepositoryTest extends TestCase
         $packages = $repository->getPackages();
         $names = array();
 
-        $this->assertEquals(2, $repository->count());
+        $this->assertEquals(3, $repository->count());
 
         $package = $packages[0];
         $names[] = $package->getName();
@@ -93,8 +110,11 @@ class PathRepositoryTest extends TestCase
         $package = $packages[1];
         $names[] = $package->getName();
 
+        $package = $packages[2];
+        $names[] = $package->getName();
+
         sort($names);
-        $this->assertEquals(array('test/path-unversioned', 'test/path-versioned'), $names);
+        $this->assertEquals(array('test/path-branch-versioned', 'test/path-unversioned', 'test/path-versioned'), $names);
     }
 
     /**