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Re: Auto-generated backup files: are they useful?


I'm +1 on removing the backup files completely. I can see how they might
have been useful in the past given the save behavior, but I think the
recent changes to that have made them obsolete. I am also someone who puts
all my projects into a git repo, so I have always found them annoying and
never even used them.

Also, did we ever even have anything like an auto-recover mechanism for
them (where if the main file failed loading it would fallback to the
backup)? I can't recall... (which probably means I never used it if we have


On Mon, Jun 29, 2020 at 8:24 PM Jon Evans <jon@xxxxxxxxxxxxx> wrote:

> Currently, KiCad automatically creates backups of schematic and PCB
> files when you save a file.
> The logic for these backups is basically: if a file already exists
> with the same name as what we are saving, copy that file to a new file
> and give it the "-bak" suffix on the file extension.
> These backups are stored next to the original file in the current
> KiCad codebase.  This understandably creates clutter that some people
> don't like (myself included) so in the project-settings branch that is
> about ready to be merged, I changed this behavior to place all these
> backups in a special backups folder for the project.
> This proved to have some complications around the handling of files
> outside the project path (which it's possible to have with
> hierarchical schematic sheets) so I need to do something else.
> After some thought, I am pretty convinced that the right thing to do
> is just *remove this backup feature entirely*.  Here's why:
> 1) It's not a very good backup:  It just stores the state from the
> last time you hit "save".  If you hit save again, your backup is blown
> up.  So, it's really like a "undo" function, but on disk, and with
> only one level of undo.
> 2) Recently I changed how we save schematic and board files to fix
> some unrelated issues people were seeing with cloud backup services.
> Before this change, if KiCad crashed or had some other serious error
> while saving a file, the file would be lost (because we used to delete
> the old file and then write a new one in its place).  After this
> change, we write the new file to a temporary location, and only if
> that write succeeds do we copy it on top of the old file.  I think
> this vulnerability to generating corrupt files if we crash was one of
> the reasons for this backup file system, and that reason is now gone.
> 3) Because it's not a very good backup, I worry that the fact that
> "bak" files exist might cause some users to have a false sense of
> security and not use a true backup system (like a version control
> system, or some other mechanism that actually backs up files
> periodically).  I want to remove this false sense of security so that
> it is more clear that users should back up their files in some way if
> they care about the work.
> In other words, I don't think this feature actually gives enough value
> to make it worth the clutter in the project folder and/or the
> development effort to make it work well with less clutter.
> So, I'd like to hear from others on this: anyone disagree?
> Thanks,
> Jon
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