Currently a deployment will only attempt to fetch and push code once. If the fetch fails, or FTP connection fails, or the FTP connection succeeds but the folder is inaccessible for whatever reason (NFS/SFS for example) deploy will give up and send a failed notification. If another user then commits some more code and this time its successful the code on your site is behind, and thats problematic.
My suggestion is to add a setting to retry x times before giving up, and if no successful deployment after x times lock the deployment as it obviously needs to be fixed.
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