fix: rescue docarray in setup (#4203)

setup.py

@@ -74,11 +74,32 @@ def add_ac(k, v):
         pass
 
 
+def rescue_docarray():
+    """Upgrading from 2.x to 3.x is broken (https://github.com/jina-ai/jina/issues/4194)
+    This function checks if docarray is broken and if so attempts to rescue it
+    """
+    try:
+        import docarray as docarray
+
+        __docarray_version__ = docarray.__version__
+
+    except AttributeError:
+        # Being here means docarray is not installed correctly, attempt to reinstall it
+        # as recommended by pip https://pip.pypa.io/en/latest/user_guide/#using-pip-from-your-program
+        import subprocess
+
+        subprocess.check_call(
+            [sys.executable, '-m', 'pip', 'uninstall', '--yes', 'docarray']
+        )
+        subprocess.check_call([sys.executable, '-m', 'pip', 'install', 'docarray'])
+
+
 class PostDevelopCommand(develop):
     """Post-installation for development mode."""
 
     def run(self):
         develop.run(self)
+        rescue_docarray()
         register_ac()
 
 
@@ -87,6 +108,7 @@ class PostInstallCommand(install):
 
     def run(self):
         install.run(self)
+        rescue_docarray()
         register_ac()