only run when no errors in __exit__, cleaned README.md

Author: jasonkena

README.md

@@ -1,11 +1,11 @@
 # MagicPickle
-`magicpickle` allows you to transfer pickled representations of objects between local and remote instances of scripts, providing a near-seamless way of write code which both accesses data stored remotely and visualizes it locally. This avoids the need to:
+`magicpickle` allows you to transfer pickled representations of objects between local and remote instances of scripts, providing a near-seamless way to write code which both accesses data stored remotely and visualizes it locally. This avoids the need to:
 - store, load, and sync intermediate data representations between local and remote machines
 - use X11 forwarding/VNC with noticable latency
 
 Internally, `magicpickle` uses `joblib` to pickle and unpickle objects, and `magic-wormhole` to transfer the pickled data between local and remote instances of a script.
 
-Note that `magicpickle` assumes that each `mp.save` is associated with a single `mp.load` in the same script (assumes that both local and remote instances have the same control flow).
+Note that `magicpickle` assumes that each `mp.save` is associated with a _single_ `mp.load` in the same script; it assumes that both local and remote instances have the same control flow.
 
 ## Installation
 ```pip install magicpickle```

magicpickle/magicpickle.py

@@ -77,7 +77,8 @@ def __enter__(self):
         return self
 
     def __exit__(self, exc_type, exc_value, traceback):
-        if not self.is_local:
+        # only run when no errors
+        if exc_type is None and self.is_remote:
             joblib.dump(self.store, self.store_path, compress=self.compress)
             command = f"wormhole send {self.store_path}"
             subprocess.run(command.split(), check=True)
@@ -90,5 +91,5 @@ def load(self):
         return self.store.pop(0)
 
     def save(self, obj):
-        assert not self.is_local, "Cannot save in local mode"
+        assert self.is_remote, "Cannot save in local mode"
         self.store.append(obj)

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "magicpickle"
-version = "0.0.2"
+version = "0.0.3"
 description = "A wrapper around magic-wormhole and joblib to send pickled objects across the internet."
 readme = "README.md"
 license = {file = "LICENSE"}