super-save 0.5: Modernized and Better Than Ever

It’s been a while since the last super-save release. The last time I wrote about it was back in 2018, when I boldly proclaimed: It seems that now super-save is beyond perfect, so don’t expect the next release any time soon! Famous last words. There was a 0.4 release in 2023 (adding a predicate system, buffer exclusions, silent saving, and trailing whitespace cleanup), but I never got around to writing about it. The package has been rock solid for years and I just didn’t pay it much attention – it quietly did its job, which is kind of the whole point of an auto-save package. A Bit of History The idea behind super-save goes all the way back to a blog post I wrote in 2012 about auto-saving buffers on buffer and window switches. I had been using IntelliJ IDEA for Java development and loved that it would save your files automatically whenever the editor lost focus. No manual C-x C-s, no thinking about it. I wanted the same behavior in Emacs. Back then, the implementation was crude – defadvice on switch-to-buffer, other-window, and the windmove commands. That code lived in Emacs Prelude for a few years before I extracted it into a standalone package in 2015. super-save was born. What Prompted This Release Yesterday I stumbled upon buffer-guardian.el, a package with very similar goals to super-save. Its README has a comparison with super-save that highlighted some valid points – mainly that super-save was still relying on advising specific commands for buffer-switch detection, while newer Emacs hooks like window-buffer-change-functions and window-selection-change-functions could do the job more reliably. The thing is, those hooks didn’t exist when super-save was created, and I didn’t rush to adopt them while Emacs 27 was still new and I wanted to support older Emacsen. But it’s 2026 now – Emacs 27.1 is ancient history. Time to modernize! What’s New in 0.5 This is the biggest super-save release in years! Here are the highlights: Modern buffer/window switch detection Buffer and window switches are now detected via window-buffer-change-functions and window-selection-change-functions, controlled by the new super-save-when-buffer-switched option (enabled by default). This catches all buffer switches – keyboard commands, mouse clicks, custom functions – unlike the old approach of advising individual (yet central) commands. Modern focus handling Frame focus loss is now detected via after-focus-change-function instead of the obsolete focus-out-hook, controlled by super-save-when-focus-lost (also enabled by default). Soft-deprecated trigger system With the new hooks in place, both super-save-triggers and super-save-hook-triggers now default to nil. You can still use them for edge cases, but for the vast majority of users, the built-in hooks cover everything. org-src and edit-indirect support super-save now knows how to save org-src edit buffers (via org-edit-src-save) and edit-indirect buffers (via edit-indirect--commit). Both are enabled by default and controlled by super-save-handle-org-src and super-save-handle-edit-indirect. Safer predicates Two new default predicates prevent data loss: verify-visited-file-modtime avoids overwriting files modified outside Emacs, and a directory existence check prevents errors when a file’s parent directory has been removed. Predicate evaluation is also wrapped in condition-case now, so a broken custom predicate logs a warning instead of silently disabling all auto-saving. Emacs 27.1 required This allowed cleaning up the code and relying on modern APIs. Upgrading For most users, upgrading is seamless – the new defaults just work. If you had a custom super-save-triggers list for buffer-switching commands, you can probably remove it entirely: ;; Before: manually listing every command that switches buffers (setq super-save-triggers '(switch-to-buffer other-window windmove-up windmove-down windmove-left windmove-right next-buffer previous-buffer)) ;; After: the window-system hooks catch all of these automatically ;; Just delete the above and use the defaults! If you need to add triggers for commands that don’t involve a buffer switch (like ace-window), super-save-triggers is still available for that. A clean 0.5 setup looks something like this: (use-package super-save :ensure t :config ;; Save buffers automatically when Emacs is idle (setq super-save-auto-save-when-idle t) ;; Don't display "Wrote file..." messages in the echo area (setq super-save-silent t) ;; Disable the built-in auto-save (backup files) since super-save handles it (setq auto-save-default nil) (super-save-mode +1)) It’s also worth noting that Emacs 26.1 introduced auto-save-visited-mode, which saves file-visiting buffers to their actual files after an idle delay. This overlaps with super-save-auto-save-when-idle, so if you prefer using the built-in for idle saves, you can combine the two: (use-package super-save :ensure t :config ;; Don't display "Wrote file..." messages in the echo area (setq super-save-silent t) ;; Disable the built-in auto-save (backup files) (setq auto-save-default nil) (super-save-mode +1)) ;; Let the built-in auto-save-visited-mode handle idle saves (auto-save-visited-mode +1) Burst-Driven Development Strikes Again Most of my Emacs packages are a fine example of what I like to call burst-driven development – long periods of stability punctuated by short intense bursts of activity. I hadn’t touched super-save in years, then spent a few hours modernizing the internals, adding a test suite, improving the documentation, and cutting a release. It was fun to revisit the package after all this time and bring it up to 2026 standards. If you’ve been using super-save, update to 0.5 and enjoy the improvements. If you haven’t tried it yet – give it a shot. Your poor fingers might thanks for you this, as pressing C-x C-s non-stop is hard work! That’s all I have for you today. Keep hacking!

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