Fix local storage caching issue

[ankush0545]

Summary

Fixes an issue in LocalStorage where existing files could remain stale due to caching behavior when writing data to the local datastore.

Changes

• Updated LocalStorage save logic to handle file writes more consistently.
• Improved behavior when files already exist.
• Ensured metadata and file contents remain synchronized after updates.

Testing

• Reproduced the issue locally.
• Verified that updated files are correctly reflected after writing.
• Ran existing tests and confirmed they pass.

Impact

This change improves reliability when using LocalStorage as a datastore backend and helps prevent stale cached data from being served.

[greptile-apps]

Greptile Summary

This PR modifies a single guard condition in LocalStorage.save_bytes with the intent of fixing stale cached data, but the change inverts the overwrite logic rather than correcting it.

• Inverted skip condition: removing not from if not overwrite and os.path.exists(full_path) causes overwrite=True calls to silently skip every existing file (never updating them) and overwrite=False calls to always overwrite existing files (ignoring the flag entirely).
• Correct original behavior: the original condition correctly skips writes only when the caller explicitly opts out of overwriting (overwrite=False) and the file already exists — reverting this change is the right course of action.

Confidence Score: 1/5

Not safe to merge — the change inverts the overwrite guard and will cause silent data-loss or incorrect skipping on every call to save_bytes where a file already exists.

The single changed line removes the not from the overwrite guard, which means any caller using overwrite=True (e.g. updating an artifact) will silently no-op on existing files, while any caller relying on the default overwrite=False to protect existing data will have those files silently replaced. Both failure modes are silent and affect core datastore write semantics.

metaflow/plugins/datastores/local_storage.py — the only changed file; the one-character edit to the overwrite guard inverts its behavior completely.

Important Files Changed

Filename	Overview
metaflow/plugins/datastores/local_storage.py	Removes not from the overwrite guard in save_bytes, inverting the skip logic so that existing files are never overwritten when overwrite=True and are always overwritten when overwrite=False.

_{Reviews (1): Last reviewed commit: "Fix local storage caching issue" | Re-trigger Greptile}

[greptile-apps]

The guard condition has been inverted, breaking the semantics of the overwrite parameter entirely. With this change, when overwrite=True (caller explicitly wants to replace an existing file) the function now skips the write and does nothing. Conversely, when overwrite=False (the default, meaning "don't replace existing files") the continue is never reached and every existing file gets silently overwritten. The base-class docstring in datastore_storage.py is clear: overwrite=False must leave existing objects untouched. Removing the not reverses both cases simultaneously.

Suggested change

	if overwrite and os.path.exists(full_path):
	continue
	if not overwrite and os.path.exists(full_path):
	continue

[talsperre]

Can you show how your reprodcuded the bug and how you fixed this?