03477: Problem with 'autosave' option and different mame versions

ID	Category [?]	Severity [?]	Reproducibility	Date Submitted	Last Update
03477	Misc.	Feature	Always	Oct 19, 2009, 19:28	Oct 19, 2009, 23:28

Tester	sz72	View Status	Public	Platform	MAME (Official Binary)
Assigned To		Resolution	Open	OS	Windows XP (32-bit)
Status [?]	Acknowledged			Driver
Version	0.134	Fixed in Version		Build	Normal
		Fixed in Git Commit		Github Pull Request #

Summary	03477: Problem with 'autosave' option and different mame versions
Description	When you set the option to automatically load/save states, if the savestate for the game was created by a different version of mame, an error message is shown and the game starts from the beginning. However, when you exit mame the savestate is overwritten with a new one and the old data is lost. This is not nice if you made an error and started the wrong version. If the autosave option is enabled but the state cannot be loaded, then nothing should be saved at exit.
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No.05035 Tafoid Administrator Oct 19, 2009, 20:18	Save States are not guaranteed to work from version to version as I'm sure you are quite aware. Most people backup any sensitive files which they deem important and don't want to lose, including these saves. I'm not sure how easy or hard it would be to do version checking on saves - I've seen saves work for several versions and also as little as one U version. Having MAME do this checking for you might not be a bad idea - so I'll pass it along for the Devs to consider.
No.05036 sz72 Tester Oct 19, 2009, 22:21	The problem is not about version checking. The problem is that since mame knows that the save state cannot be loaded (otherwise it would not show the error message on the screen) it should not overwrite it if autosave is enabled.
No.05037 Tafoid Administrator Oct 19, 2009, 23:28	The problem is that MAME doesn't know that any given save state is compatible or not. It's assumed that it is and attempts to load the current save or autosave regardless of version. If the game you are playing has had any type of changes - it's likely the data saved from one version to another will not be what the current MAME would expect and tells you that you are unable to load the save. That's my understanding of the save function, anyway.