Magit with tramp leaves temporary files in repository

[laudrup]

I confirm that...

• I searched the FAQ, issue tracker, discussions board, documentation, and wiki, and did not find an answer to my question.

• Any discussions with or conclusions derived from the use of LLMs will be omitted from my question.

What is your question?

When using magit with a tramp/ssh connection to a remote host, I get a lot of files with a pattern similar to:

#e47ad05cdf18bc34d69df0d782ea216e1c180392#.~;0f6e0f8538628bb10e9436831351f7564cea165b~

which seems to contain a copy of files with changes not yet commited. These files are still present even after commiting changes ending up cluttering the repository. It seems like I have to remove these files manually.

This is of course just a minor annoyance and I could limit it by adding those to my .gitgnore but that doesn't really solve the actual problem.

It has been a bit hard for me to try to find anything related to this issue as this doesn't seem to be related to where tramp stores temporary files (they are in /tmp as expected) and it's kind of hard to search for a pattern matching these files.

I also don't know if this is actually related to doom emacs but I haven't done any special configuration so this is just magit+tramp "out of the box" with doom emacs.

Any way to avoid having to clean up these files would be appreciated as well as pointers to where I might find more information.

Thanks a lot.

System information

https://gist.github.com/laudrup/33ea96dc60a335316967ca26d0956ba4

[AjaiKN]

I think this is a bug in Doom. I noticed it a while ago and fixed it in my private config, but I never got around to reporting it to Doom. Does adding the following to your config.el fix the issue?

;; in $DOOMDIR/config.el

(setq tramp-auto-save-directory "~/.cache/doom/tramp-autosave/")

(after! doom-editor
  ;; TODO: PR or issue
  (defadvice! doom-make-hashed-auto-save-file-name-a (fn)
    "Compress the auto-save file name so paths don't get too long."
    :around #'make-auto-save-file-name
    (let ((buffer-file-name
           (if (or
                ;; Don't do anything for non-file-visiting buffers. Names
                ;; generated for those are short enough already.
                (null buffer-file-name)
                ;; If an alternate handler exists for this path, bow out. Most of
                ;; them end up calling `make-auto-save-file-name' again anyway, so
                ;; we still achieve this advice's ultimate goal.
                (find-file-name-handler buffer-file-name
                                        'make-auto-save-file-name))
               buffer-file-name
             ;;CHANGED
             (concat (or (and (string-match-p "/tramp-autosave/" buffer-file-name)
                              (file-name-directory buffer-file-name))
                         "")
                     (sha1 buffer-file-name)))))
      (funcall fn))))

[laudrup]

I can confirm that this does indeed seem to fix the issue. Thanks a lot.

I haven't done a lot of testing but I'll let you know if I encounter some issues.

[hlissner]

The tramp defaults were moved to a new :emacs tramp module in doomemacs/core@71eae25. So tramp-backup-directory-alist and tramp-auto-save-directory were moved. If you weren't using the new module, then tramp is saving temp files to their Emacs default location: the current working directory.

The quick fix is to enable :emacs tramp.

Otherwise, a much simpler version of AjaKN's fix:

(setq tramp-auto-save-directory (concat doom-cache-dir "tramp-autosave/")
      tramp-backup-directory-alist backup-directory-alist)

In any case, I'll move these two variables back to Doom core soon so the module isn't required for these files.

[wchmb]

Could you see if this snippet fixes the issue?

It works
wow, that's obscure }:)

[wchmb]

forget my previous comment. It's still appearing
I tried with doomemacs/core@2c682d6

[laudrup]

Ah I see. Perhaps this is what is needed?

;;; add to $DOOMDIR/config.el
(setq auto-save-file-name-transforms
      `(("\\`/[^/]*:\\([^/]*/\\)*\\([^/]*\\)\\'"
         ,(concat auto-save-list-file-prefix "tramp-\\2") t)
        (".*" ,auto-save-list-file-prefix t)))

@laudrup Could you see if this snippet fixes the issue (without @AjaiKN's fix)?

Unfortunately that doesn't seem to fix the issue.

The fix from @AjaiKN still works though.

[hlissner]

Ah, forgot to post here. Yesterday, with the help of someone on Discord, I was able to reproduce the issue and discovered the cause of it. I pushed a fix a short while ago: doomemacs/core@8f31710

Update Doom and let me know if the issue persists after that.

[laudrup]

@hlissner

I can confirm that after upgrading doom to a release with your commit the issue is no longer present.

Thanks a lot for your work and help with this all of you.

[laudrup]

Fixed with doomemacs/core@8f31710

[hpfr]

Prefixing TRAMP auto save files goes all the way back to doomemacs/core@9bbdacc, but it’s not really necessary. You can check buffer-file-name, buffer-auto-save-file-name, and (secure-hash 'sha1 buffer-file-name) to confirm that the hash uses the full Emacs file name, including the TRAMP method and host, so editing /etc/fstab on any number hosts won’t auto save to the same place.

But setting tramp-auto-save-directory takes precedence over auto-save-file-name-transforms, so I’m pretty sure the special TRAMP transform is never used anyway.

You should be able to drop tramp-auto-save-directory and simplify to:

;; Write all auto-save files to the same directory as session auto-save
;; lists. Hash filenames to avoid any filesystem name length
;; limitations. ‘tramp-auto-save-directory’ bypasses the hash transform,
;; so leave it unset.
(setq auto-save-file-name-transforms `((".*" ,auto-save-list-file-prefix sha1)))

TRAMP autosave files won’t have a special prefix, but prefixing an opaque hash isn’t that useful anyway. The actual mappings from file names to autosave file names can be found in the autosave list files in the same auto-save-list-file-prefix directory.

[hlissner]

But setting tramp-auto-save-directory takes precedence over auto-save-file-name-transforms, so I’m pretty sure the special TRAMP transform is never used anyway.

tramp-auto-save-directory was dropped in doomemacs/core@8f31710 for that reason, in favor of the transform rule.

Prefixing TRAMP auto save files goes all the way back to doomemacs/core@9bbdacc, but it’s not really necessary.

Yeah, I was playing it safe with sha1's lack of collision resistance, but, in hindsight, the risk likely isn't real enough to warrant a separate rule.

[hlissner]

After thinking on it a bit, I landed on doomemacs/core@12e6027 — I added a filename prefix to the auto-save files, so they're recognizable to anyone inspecting those files outside of Emacs for whatever reason (e.g. in a critical data loss scenario). In which case, namespacing the tramp auto-save files makes a little more sense.

[hpfr]

tramp-auto-save-directory was dropped in doomemacs/doomemacs@8f31710 for that reason, in favor of the transform rule.

True! Must have got my wires crossed spelunking through the blame.

Yeah, I was playing it safe with sha1's lack of collision resistance, but, in hindsight, the risk likely isn't real enough to warrant a separate rule.

After thinking on it a bit, I landed on doomemacs/doomemacs@12e6027 — I added a filename prefix to the auto-save files, so they're recognizable to anyone inspecting those files outside of Emacs for whatever reason (e.g. in a critical data loss scenario). In which case, namespacing the tramp auto-save files makes a little more sense.

Sounds good.