Forcing save of help buffer at exit or magit

[ErikNatanael]

Not right away, but a while into editing a rust project with rustic, whenever I try to open magit or close the program emacs requests that I save a file containing help buffer examples e.g.

let x = 1.0f32;
let y = 2.0f32;

assert_eq!(x.max(y), y);

or

let mut v = vec![1, 2, 3];
assert_eq!(v.remove(1), 2);
assert_eq!(v, [1, 3]);

I don't think I ever see these examples in emacs. The default file name for this file is markdown-code-fontification:rustic-mode.

There seems to be no way to avoid saving this file and still move on with magit/exiting. I haven't found exactly what triggers this behaviour yet and I don't know how to go about debugging it. Is there something I can run in emacs to get a log that might show what's going on?

[njsmith]

!!! I'm not alone! This just suddenly started happening to me a few hours ago, and it's been driving me up the wall. Except, in my case, I wasn't prompted for a default file name, so it was even more mysterious. (Probably ido hid the default?) I finally ran (display-buffer (list-buffers-noselect nil (buffer-list))) to get a list of hidden buffers, and then found markdown-code-fontification:rustic-mode in that list. (Notice the leading space, which makes it a hidden buffer.) And then that led me here.

These buffers appear to be created by markdown-mode, rather than rustic directly, as part of its code for fontifying fenced code blocks inside markdown files:

https://github.com/jrblevin/markdown-mode/blob/58f2d22526ac1e4abd4ee1afff8624d2dd3123d3/markdown-mode.el#L8702

So I guess the questions are:

• Why is something going around fontifying markdown files in the background while we're editing rust code?

  The code in these files appears to be taken from the official rust docs. E.g., here's your first example: https://doc.rust-lang.org/std/primitive.f32.html#method.max

  So it must be somehow related to rustic or lsp-mode's doc browsing functionality? Though I tried disabling all that via (setq lsp-eldoc-hook nil) (setq lsp-ui-doc-enable nil), and that didn't change anything.

• Why are we getting prompted to save these buffers that are supposed to be invisible scratch buffers?

Using toggle-debug-on-quit, I was able to get a backtrace at the prompt to save the file:

Debugger entered--Lisp error: (quit)
  read-from-minibuffer("File to save in: ~/learn-rust/ovi/src/vocab/" nil (keymap (24 keymap (4 . ignore) (2 . ignore)) keymap (27 keymap (108 . ido-toggle-literal)) (23 . ido-copy-current-file-name) (15 . ido-copy-current-word) (11 . ido-delete-file-at-head) keymap (3 keymap (19 lambda nil (interactive) (ido-initiate-auto-merge (current-buffer)))) (27 keymap (115 . ido-merge-work-directories) (112 . ido-prev-work-directory) (15 . ido-next-work-file) (111 . ido-prev-work-file) (110 . ido-next-work-directory) (109 . ido-make-directory) (107 . ido-forget-work-directory) (102 . ido-wide-find-file-or-pop-dir) (118 . ido-push-dir-first) (98 . ido-push-dir) (100 . ido-wide-find-dir-or-delete-dir)) (12 . ido-reread-directory) (C-backspace . ido-up-directory) (remap keymap (backward-kill-word . ido-delete-backward-word-updir) (delete-backward-char . ido-delete-backward-updir)) (127 . ido-delete-backward-updir) (backspace . ido-delete-backward-updir) (M-down . ido-next-work-directory) (M-up . ido-prev-work-directory) (up . ido-prev-match-dir) (down . ido-next-match-dir) (24 keymap (4 . ido-enter-dired) (6 . ido-fallback-command) (2 . ido-enter-switch-buffer)) keymap (4 . ido-magic-delete-char) (6 . ido-magic-forward-char) (2 . ido-magic-backward-char) (63 . ido-completion-help) (left . ido-prev-match) (right . ido-next-match) (0 . ido-restrict-to-matches) (27 keymap (32 . ido-take-first-match)) (67108896 . ido-restrict-to-matches) (26 . ido-undo-merge-work-directory) (20 . ido-toggle-regexp) (67108908 . ido-prev-match) (67108910 . ido-next-match) (19 . ido-next-match) (18 . ido-prev-match) (16 . ido-toggle-prefix) (13 . ido-exit-minibuffer) (10 . ido-select-text) (32 . ido-complete-space) (9 . ido-complete) (5 . ido-edit-input) (3 . ido-toggle-case) (1 . ido-toggle-ignore) keymap (menu-bar keymap (minibuf "Minibuf" keymap (previous menu-item "Previous History Item" previous-history-element :help "Put previous minibuffer history element in the min...") (next menu-item "Next History Item" next-history-element :help "Put next minibuffer history element in the minibuf...") (isearch-backward menu-item "Isearch History Backward" isearch-backward :help "Incrementally search minibuffer history backward") (isearch-forward menu-item "Isearch History Forward" isearch-forward :help "Incrementally search minibuffer history forward") (return menu-item "Enter" exit-minibuffer :key-sequence "\15" :help "Terminate input and exit minibuffer") (quit menu-item "Quit" abort-recursive-edit :help "Abort input and exit minibuffer") "Minibuf")) (13 . exit-minibuffer) (10 . exit-minibuffer) (7 . abort-minibuffers) (C-tab . file-cache-minibuffer-complete) ...) nil ido-file-history)
  #f(compiled-function (item prompt hist &optional default require-match initial) "Perform the `ido-read-buffer' and `ido-read-file-name' functions.\nReturn the name of a buffer or file selected.\nPROMPT is the prompt to give to the user.\nDEFAULT if given is the default item to start with.\nIf REQUIRE-MATCH is non-nil, an existing file must be selected.\nIf INITIAL is non-nil, it specifies the initial input string." #<bytecode 0x1780b0db440a03e7>)(file "File to save in: " ido-file-history "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil)
  ad-Advice-ido-read-internal(#f(compiled-function (item prompt hist &optional default require-match initial) "Perform the `ido-read-buffer' and `ido-read-file-name' functions.\nReturn the name of a buffer or file selected.\nPROMPT is the prompt to give to the user.\nDEFAULT if given is the default item to start with.\nIf REQUIRE-MATCH is non-nil, an existing file must be selected.\nIf INITIAL is non-nil, it specifies the initial input string." #<bytecode 0x1780b0db440a03e7>) file "File to save in: " ido-file-history "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil)
  apply(ad-Advice-ido-read-internal #f(compiled-function (item prompt hist &optional default require-match initial) "Perform the `ido-read-buffer' and `ido-read-file-name' functions.\nReturn the name of a buffer or file selected.\nPROMPT is the prompt to give to the user.\nDEFAULT if given is the default item to start with.\nIf REQUIRE-MATCH is non-nil, an existing file must be selected.\nIf INITIAL is non-nil, it specifies the initial input string." #<bytecode 0x1780b0db440a03e7>) (file "File to save in: " ido-file-history "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil))
  ido-read-internal(file "File to save in: " ido-file-history "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil)
  ido-read-file-name("File to save in: " nil "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil nil)
  apply(ido-read-file-name ("File to save in: " nil "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil nil))
  #f(advice-wrapper :override read-file-name-default ido-read-file-name)("File to save in: " nil "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-..." nil nil nil)
  read-file-name("File to save in: " nil "/home/njs/learn-rust/ovi/src/vocab/ markdown-code-...")
  basic-save-buffer(nil)
  save-buffer()
  #f(compiled-function (&optional arg pred) "Save some modified file-visiting buffers.  Asks user about each one.\nYou can answer `y' or SPC to save, `n' or DEL not to save, `C-r'\nto look at the buffer in question with `view-buffer' before\ndeciding, `d' to view the differences using\n`diff-buffer-with-file', `!' to save the buffer and all remaining\nbuffers without any further querying, `.' to save only the\ncurrent buffer and skip the remaining ones and `q' or RET to exit\nthe function without saving any more buffers.  `C-h' displays a\nhelp message describing these options.\n\nThis command first saves any buffers where `buffer-save-without-query' is\nnon-nil, without asking.\n\nOptional argument ARG (interactively, prefix argument) non-nil means save\nall with no questions.\nOptional second argument PRED determines which buffers are considered:\nIf PRED is nil, all the file-visiting buffers are considered.\nIf PRED is t, then certain non-file buffers will also be considered.\nIf PRED is a zero-argument function, it indicates for each buffer whether\nto consider it or not when called with that buffer current.\nPRED defaults to the value of `save-some-buffers-default-predicate'.\n\nSee `save-some-buffers-action-alist' if you want to\nchange the additional actions you can take on files." (interactive "P") #<bytecode 0x11071be8f23a04c0>)(nil #f(compiled-function () #<bytecode -0x11f0642bc6f2fcd2>))
  apply(#f(compiled-function (&optional arg pred) "Save some modified file-visiting buffers.  Asks user about each one.\nYou can answer `y' or SPC to save, `n' or DEL not to save, `C-r'\nto look at the buffer in question with `view-buffer' before\ndeciding, `d' to view the differences using\n`diff-buffer-with-file', `!' to save the buffer and all remaining\nbuffers without any further querying, `.' to save only the\ncurrent buffer and skip the remaining ones and `q' or RET to exit\nthe function without saving any more buffers.  `C-h' displays a\nhelp message describing these options.\n\nThis command first saves any buffers where `buffer-save-without-query' is\nnon-nil, without asking.\n\nOptional argument ARG (interactively, prefix argument) non-nil means save\nall with no questions.\nOptional second argument PRED determines which buffers are considered:\nIf PRED is nil, all the file-visiting buffers are considered.\nIf PRED is t, then certain non-file buffers will also be considered.\nIf PRED is a zero-argument function, it indicates for each buffer whether\nto consider it or not when called with that buffer current.\nPRED defaults to the value of `save-some-buffers-default-predicate'.\n\nSee `save-some-buffers-action-alist' if you want to\nchange the additional actions you can take on files." (interactive "P") #<bytecode 0x11071be8f23a04c0>) (nil #f(compiled-function () #<bytecode -0x11f0642bc6f2fcd2>)))
  rustic-save-some-buffers-advice(#f(compiled-function (&optional arg pred) "Save some modified file-visiting buffers.  Asks user about each one.\nYou can answer `y' or SPC to save, `n' or DEL not to save, `C-r'\nto look at the buffer in question with `view-buffer' before\ndeciding, `d' to view the differences using\n`diff-buffer-with-file', `!' to save the buffer and all remaining\nbuffers without any further querying, `.' to save only the\ncurrent buffer and skip the remaining ones and `q' or RET to exit\nthe function without saving any more buffers.  `C-h' displays a\nhelp message describing these options.\n\nThis command first saves any buffers where `buffer-save-without-query' is\nnon-nil, without asking.\n\nOptional argument ARG (interactively, prefix argument) non-nil means save\nall with no questions.\nOptional second argument PRED determines which buffers are considered:\nIf PRED is nil, all the file-visiting buffers are considered.\nIf PRED is t, then certain non-file buffers will also be considered.\nIf PRED is a zero-argument function, it indicates for each buffer whether\nto consider it or not when called with that buffer current.\nPRED defaults to the value of `save-some-buffers-default-predicate'.\n\nSee `save-some-buffers-action-alist' if you want to\nchange the additional actions you can take on files." (interactive "P") #<bytecode 0x11071be8f23a04c0>) nil #f(compiled-function () #<bytecode -0x11f0642bc6f2fcd2>))
  apply(rustic-save-some-buffers-advice #f(compiled-function (&optional arg pred) "Save some modified file-visiting buffers.  Asks user about each one.\nYou can answer `y' or SPC to save, `n' or DEL not to save, `C-r'\nto look at the buffer in question with `view-buffer' before\ndeciding, `d' to view the differences using\n`diff-buffer-with-file', `!' to save the buffer and all remaining\nbuffers without any further querying, `.' to save only the\ncurrent buffer and skip the remaining ones and `q' or RET to exit\nthe function without saving any more buffers.  `C-h' displays a\nhelp message describing these options.\n\nThis command first saves any buffers where `buffer-save-without-query' is\nnon-nil, without asking.\n\nOptional argument ARG (interactively, prefix argument) non-nil means save\nall with no questions.\nOptional second argument PRED determines which buffers are considered:\nIf PRED is nil, all the file-visiting buffers are considered.\nIf PRED is t, then certain non-file buffers will also be considered.\nIf PRED is a zero-argument function, it indicates for each buffer whether\nto consider it or not when called with that buffer current.\nPRED defaults to the value of `save-some-buffers-default-predicate'.\n\nSee `save-some-buffers-action-alist' if you want to\nchange the additional actions you can take on files." (interactive "P") #<bytecode 0x11071be8f23a04c0>) (nil #f(compiled-function () #<bytecode -0x11f0642bc6f2fcd2>)))
  save-some-buffers(nil #f(compiled-function () #<bytecode -0x11f0642bc6f2fcd2>))
  magit-save-repository-buffers(nil)
  magit-maybe-save-repository-buffers()
  run-hooks(magit-pre-call-git-hook)
  magit-call-git("update-index" "--add" "--remove" "--ignore-skip-worktree-entries" "--" ("src/vocab/requirement.rs"))
  magit-wip-commit-worktree("refs/heads/master" ("src/vocab/requirement.rs") "autosave src/vocab/requirement.rs after save")
  magit-wip-commit-buffer-file()
  run-hooks(after-save-hook)
  basic-save-buffer(t)
  save-buffer(1)
  funcall-interactively(save-buffer 1)
  #<subr call-interactively>(save-buffer nil nil)
  apply(#<subr call-interactively> save-buffer (nil nil))
  call-interactively@ido-cr+-record-current-command(#<subr call-interactively> save-buffer nil nil)
  apply(call-interactively@ido-cr+-record-current-command #<subr call-interactively> (save-buffer nil nil))
  call-interactively(save-buffer nil nil)
  command-execute(save-buffer)

So it looks like the magit connection is that magit-save-repository-buffers is calling save-some-buffers, which triggers rustic's save-some-buffers advice, and then calls save-buffer on the markdown-code-fontification:rustic-mode buffer.

Oddities: magit-save-repository-buffers is only supposed to try to save buffers that are visiting files, which the weird markdown buffer isn't. Also, the rustic advice might be a red herring -- it looks like it's just:

(defun rustic-save-some-buffers-advice (orig-fun &rest args)
  (let ((rustic-format-trigger nil)
        (rustic-format-on-save nil))
    (apply orig-fun args)))

and I don't see how that would cause save-buffer to be triggered on a buffer that it shouldn't be.

I guess the next steps would be to somehow figure out who's creating the markdown buffer, and to trace through magit-save-repository-buffers to figure out why it's prompting about a buffer that isn't visiting a file.

[njsmith]

Ah ha, using debug-on-entry I figured out what's making those markdown buffers:

Debugger entered--entering a function:
* markdown-fontify-code-block-natively(nil 157 344)
  markdown-fontify-code-blocks-generic(markdown-match-gfm-code-blocks 347)
  markdown-fontify-gfm-code-blocks(347)
  font-lock-fontify-keywords-region(1 347 nil)
  font-lock-default-fontify-region(1 347 nil)
  font-lock-fontify-region(1 347)
  #f(compiled-function (beg end) #<bytecode -0x19eb5bcfb35cf707>)(1 347)
  font-lock-ensure()
  lsp--fontlock-with-mode("Creates an iterator from a value.\n\nSee the [module..." lsp--render-markdown)
  lsp--render-string("Creates an iterator from a value.\n\nSee the [module..." "markdown")
  lsp--render-element(#<hash-table equal 2/2 0x1594914bdd03>)
  lsp--signature->message(#<hash-table equal 2/2 0x1594914bdc57>)
  lsp--handle-signature-update(#<hash-table equal 2/2 0x1594914bdc57>)
  #f(compiled-function (result) #<bytecode 0x1696e84cc287387f>)(#<hash-table equal 2/2 0x1594914bdc57>)
  #f(compiled-function (result) #<bytecode -0x7e3646432b1be68>)(#<hash-table equal 2/2 0x1594914bdc57>)
  lsp--parser-on-message(#<hash-table equal 3/3 0x1594914bdc01> #s(lsp--workspace :ewoc nil :server-capabilities #<hash-table equal 23/23 0x15948fed7ddf> :registered-server-capabilities (#s(lsp--registered-capability :id "workspace/didChangeWatchedFiles" :method "workspace/didChangeWatchedFiles" :options #<hash-table equal 1/1 0x1594904a9d85>) #s(lsp--registered-capability :id "workspace/didChangeWatchedFiles" :method "workspace/didChangeWatchedFiles" :options #<hash-table equal 1/1 0x159490288443>) #s(lsp--registered-capability :id "workspace/didChangeWatchedFiles" :method "workspace/didChangeWatchedFiles" :options #<hash-table equal 1/1 0x15949047b6d9>) #s(lsp--registered-capability :id "workspace/didChangeWatchedFiles" :method "workspace/didChangeWatchedFiles" :options #<hash-table equal 1/1 0x15949047bc55>)) :root "/home/njs/learn-rust/ovi" :client #s(lsp--client :language-id nil :add-on? nil :new-connection (:connect #f(compiled-function (filter sentinel name environment-fn) #<bytecode -0x1db8dbc7593a38c2>) :test\? #f(compiled-function () #<bytecode -0x1dd7b18ab8bb5dfb>)) :ignore-regexps nil :ignore-messages nil :notification-handlers #<hash-table equal 1/65 0x15948fa7fa57> :request-handlers #<hash-table equal 0/65 0x15948fe82107> :response-handlers #<hash-table eql 106/145 0x15948fe9d08f> :prefix-function nil :uri-handlers #<hash-table equal 0/65 0x1594900b2207> :action-handlers #<hash-table equal 3/65 0x15949008e093> :major-modes (rust-mode rustic-mode) :activation-fn nil :priority 1 :server-id rust-analyzer :multi-root nil :initialization-options lsp-rust-analyzer--make-init-options :semantic-tokens-faces-overrides nil :custom-capabilities ((experimental (snippetTextEdit . t))) :library-folders-fn #f(compiled-function (workspace) #<bytecode -0x47e8177f0d718f8>) :before-file-open-fn nil :initialized-fn nil :remote? nil :completion-in-comments? nil :path->uri-fn nil :uri->path-fn nil :environment-fn nil :after-open-fn #f(compiled-function () #<bytecode 0x1fc996be6a4d>) :async-request-handlers #<hash-table equal 0/65 0x15948fa54bed> :download-server-fn #f(compiled-function (client callback error-callback update\?) #<bytecode 0x1730d1e8428199a3>) :download-in-progress? nil :buffers nil) :host-root nil :proc #<process rust-analyzer> :cmd-proc #<process rust-analyzer> :buffers (#<buffer requirement.rs>) :semantic-tokens-faces nil :semantic-tokens-modifier-faces nil :extra-client-capabilities nil :status initialized :metadata #<hash-table equal 0/65 0x15948f93e4d5> :watches #<hash-table equal 0/65 0x15948f95d629> :workspace-folders nil :last-id 0 :status-string nil :shutdown-action nil :diagnostics #<hash-table equal 1/65 0x15948f963677> :work-done-tokens #<hash-table equal 0/65 0x15948f97cf27>))
  #f(compiled-function (proc input) #<bytecode 0x4dce07ca3570b28>)(#<process rust-analyzer> "Content-Length: 611\15\n\15\n{\"jsonrpc\":\"2.0\",\"id\":1313,...")

[njsmith]

...OK I think I might have figured out what's happening. But I still don't know whose bug it is!

• In save-some-buffers, it first saves all buffers where buffer-save-without-query is enabled, without checking if they're visiting a file, and without checking the "predicate" that you can pass it to restrict to a certain set of files (as e.g. magit does, when trying to automatically save all files in your current git workspace)
• lsp-mode for some reason is creating hidden markdown buffers based on text send from rust-analyzer
• markdown-mode is extracting bits of those markdown buffers and creating hidden rustic buffers
• I have buffer-save-without-query set to t in rustic buffers, as recommended by the top google hit for setting up rust + emacs. (But in fact I enabled it from prog-mode-hook, because this is nice everywhere; the only connection to rust is that I didn't know about it until I found that post.)

And I confirmed this analysis by manually switching to the hidden markdown-code-fontification buffer and toggling buffer-save-without-query on and off; when it was on then save-some-buffers gave the prompt to save it, and when it was off, it didn't.

So first... the one package that doesn't appear in this list is rustic. So maybe this bug is on the wrong repo? Not sure.

It's very surprising that save-some-buffers will try to save buffers that aren't visiting any file, and don't match the predicate. That seems like a bug in emacs upstream?

In the mean time, setting buffer-save-without-query to t in non-file-visiting-buffers is probably a bad idea! Maybe we should nudge @rksm to update that blog post?

I've just updated my hook to do:

    (if buffer-file-name
        (setq-local buffer-save-without-query t))

and that seems to be working so far.

[rksm]

@njsmith Good point and good workaround, will update the guide accordingly until this has been fixed. Thank you!

[cgfork]

m

[brotzeit]

Sorry for the delay. It seems we currently "save some buffers" twice. First with regular save-some-buffers with formatting disabled and then we run rustic-save-some-buffers when starting compilation/formatting.

rustic-save-some-buffers does check if a buffer belongs to the current rust project.

Can you do me a favor and give this a try

modified   rustic-rustfmt.el
@@ -347,7 +347,8 @@ non-nil."
 (defun rustic-save-some-buffers-advice (orig-fun &rest args)
   (let ((rustic-format-trigger nil)
         (rustic-format-on-save nil))
-    (apply orig-fun args)))
+    (unless (eq major-mode 'rustic-mode)
+      (apply orig-fun args))))
 
 (advice-add 'save-some-buffers :around
             #'rustic-save-some-buffers-advice)

[brotzeit]

I just realized this won't work. Let me think about it =)

[brotzeit]

I've just updated my hook to do:

(if buffer-file-name
    (setq-local buffer-save-without-query t))

and that seems to be working so far.

If this is true, rustic can't be the reason for this issue.

We do the same in rustic-save-some-buffers

  (let ((buffers (cl-remove-if-not
                  #'buffer-file-name
                  (if (fboundp rustic-list-project-buffers-function)
                      (funcall rustic-list-project-buffers-function)
                    (buffer-list))))

Regarding

Oddities: magit-save-repository-buffers is only supposed to try to save buffers that are visiting files, which the weird markdown buffer isn't. Also, the rustic advice might be a red herring -- it looks like it's just:

(defun rustic-save-some-buffers-advice (orig-fun &rest args)
(let ((rustic-format-trigger nil)
(rustic-format-on-save nil))
(apply orig-fun args)))

and I don't see how that would cause save-buffer to be triggered on a buffer that it shouldn't be.

@njsmith is right, this advice just turns off formatting when calling save-some-buffers.

Usually I keep issues like this open for others, but in this case I want to avoid confusions because I'm nearly 100% sure this is not a rustic issue.

[granitrocky]

I know this issue is closed, but to anyone who finds this bug in the future, I have an open PR over at markdown-mode that fixes this.