mpickering commented 9 years ago

When haskell-mode offers to add a language pragma or a cabal package dependency, emacs becomes unresponsive. C-g does not make emacs responsive. The only way to continue working with emacs is to kill the ghc process.

Emacs setting

In GNU Emacs 24.5.1 (x86_64-w64-mingw32) of 2015-04-12 on KAEL Windowing system distributor Microsoft Corp.', version 6.1.7601 Configured using: configure --prefix=/z/emacs --host=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --with-wide-int --with-jpeg --with-xpm --with-png --with-tiff --with-rsvg --with-xml2 --with-gnutls --with-sound=yes --with-file-notification=yes --without-dbus --without-imagemagick 'CFLAGS=-Ofast -fomit-frame-pointer -funroll-loops -g0 -pipe' 'LDFLAGS=-static-libgcc -static-libstdc++ -static -s -Wl,-s''

Important settings: value of $LANG: en_US.UTF-8 locale-coding-system: cp1252

Major mode: Haskell

Minor modes in effect: global-semanticdb-minor-mode: t global-semantic-idle-scheduler-mode: t semantic-mode: t diff-auto-refine-mode: t yas-minor-mode: t haskell-indentation-mode: t shell-dirtrack-mode: t interactive-haskell-mode: t flycheck-mode: t show-paren-mode: t global-hl-line-mode: t elscreen-persist-mode: t desktop-save-mode: t delete-selection-mode: t auto-insert-mode: t guru-global-mode: t guru-mode: t ido-everywhere: t display-time-mode: t tooltip-mode: t electric-indent-mode: t mouse-wheel-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t column-number-mode: t line-number-mode: t transient-mark-mode: t

Features: (pp shadow sort mail-extr emacsbug sendmail calculator semantic/edit semantic/tag-write jtags-extras jtags superword subword semantic/db-file data-debug cedet-files semantic/wisent/java-tags semantic/java semantic/decorate/include semantic/db-find semantic/db-ref semantic/decorate/mode semantic/decorate pulse semantic/doc semantic/wisent/javat-wy semantic/wisent semantic/wisent/wisent semantic/db-mode semantic/db eieio-base semantic/idle semantic/format ezimage semantic/tag-ls semantic/find semantic/ctxt semantic/util-modes semantic/util semantic semantic/tag semantic/lex semantic/fw mode-local cedet cc-langs browse-url autorevert filenotify log-edit message rfc822 mml mml-sec mm-decode mm-bodies mm-encode mail-parse rfc2231 rfc2047 rfc2045 ietf-drums mailabbrev gmm-utils mailheader pcvs-util add-log diff-mode vc-bzr vc-sccs vc-svn vc-cvs vc-rcs vc-dir ewoc vc vc-dispatcher autopair cl-macs smex hippie-exp misearch multi-isearch thingatpt vc-git java-snippets yasnippet haskell-indentation haskell-doc eldoc inf-haskell haskell-decl-scan imenu shell haskell haskell-completions haskell-load haskell-commands highlight-uses-mode haskell-modules haskell-sandbox haskell-repl haskell-debug haskell-interactive-mode haskell-presentation-mode haskell-collapse haskell-navigate-imports haskell-compile haskell-process haskell-session haskell-cabal haskell-utils url-util url-parse auth-source eieio byte-opt bytecomp byte-compile cl-extra haskell-font-lock pcase cconv eieio-core password-cache url-vars json flycheck help-mode subr-x dash ghc ghc-indent ghc-ins-mod ghc-command ghc-check ghc-doc ghc-info ghc-comp ghc-rewrite ghc-process ghc-func haskell-mode haskell-string haskell-sort-imports haskell-lexeme rx haskell-align-imports haskell-compat haskell-complete-module flymake etags compile dabbrev haskell-customize saveplace org-w3m org-irc org-info org-bibtex bibtex org-bbdb ob-plantuml ob-latex ob-haskell ob-C cc-mode cc-fonts cc-guess cc-menus cc-cmds cc-styles cc-align cc-engine cc-vars cc-defs paren gnus gnus-ems nnheader gnus-util mail-utils mm-util mail-prsvr wid-edit hl-line elscreen-persist revive desktop frameset delsel autoinsert cus-start cus-load ws-butler cl gv mule-util elscreen dired guru-mode edmacro kmacro cl-loaddefs cl-lib ido ox-latex ox-icalendar ox-html ox-ascii ox-publish ox org-element avl-tree org advice help-fns org-macro org-footnote org-pcomplete pcomplete org-list org-faces org-entities noutline outline easy-mmode org-version ob-emacs-lisp ob ob-tangle ob-ref ob-lob ob-table ob-exp org-src ob-keys ob-comint comint ansi-color ring ob-core ob-eval org-compat org-macs org-loaddefs find-func cal-menu calendar cal-loaddefs format-spec org-install boron-theme tex-site info easymenu package epg-config time time-date tooltip electric uniquify ediff-hook vc-hooks lisp-float-type mwheel dos-w32 ls-lisp w32-common-fns disp-table w32-win w32-vars tool-bar dnd fontset image regexp-opt fringe tabulated-list newcomment lisp-mode prog-mode register page menu-bar rfn-eshadow timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core frame cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese case-table epa-hook jka-cmpr-hook help simple abbrev minibuffer nadvice loaddefs button faces cus-face macroexp files text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote make-network-process w32notify w32 multi-tty emacs)

Memory information: ((conses 16 542652 80020) (symbols 56 47672 0) (miscs 48 1044 1302) (strings 32 111366 10681) (string-bytes 1 3560275) (vectors 16 52504) (vector-slots 8 1051076 12779) (floats 8 312 323) (intervals 56 11372 4138) (buffers 960 43))

gracjan commented 9 years ago

Thanks.

dysinger commented 9 years ago

I'm also experiencing this crash every single time on the latest melpa release.

I'm on Emacs 24 on Ubuntu 15.04

gracjan commented 9 years ago

This is very surprising, at least the LANGUAGE pragma. We use precomputed list of available extensions, so there should be no interaction with ghc at this point.

vejkse commented 9 years ago

I’m also using the latest melpa release with emacs 24.5.1 and I can bring a few precisions:

emacs recovers its responsiveness after hitting C-g 3 times (or, as said above, killing ghc, but this is unnecessary, at least in my case);
the answers (y/n) are not discarded, but inserted into the source code once emacs is responsive again;
it happens also when unnecessary imports are suggested for removal.

Edit: I investigated the question further and it seems that I found the culprit: when haskell-doc-mode is turned on, the problem is present, but disappears when it’s turned off. It’s not that simple, however: there is no problem the first time I’m proposed to remove an unnecessary import, even with haskell-doc-mode on [at least when I’ve done nothing else before].

rainbyte commented 8 years ago

Hi. We are experiencing this behavior with release 13.18, using Emacs 24.5.1 on Arch Linux.

Please let me know if I can provide you with any further information.

gracjan commented 8 years ago

@geraldus: Can you try to find out what is going on here?

geraldus commented 8 years ago

@gracjan there was some issues related to doc-mode in past if I'm not mistaken.

Apologize pals, I will be able to put my hands on this issue only in the middle of next week.

geraldus commented 8 years ago

@gracjan ok, one small notice:

This is very surprising, at least the LANGUAGE pragma. We use precomputed list of available extensions, so there should be no interaction with ghc at this point.

we are talking not about language pragma being inserted manually, Emacs hangs when offers to insert language pragma automatically or when offers to remove redundant imports (I believe this happens when starting/loading/reloading interactive process). If I'm not mistaken I had same issue with doc-mode long ago. I'll share my further investigations here.

geraldus commented 8 years ago

Ok, I was able to reproduce this:

turn on haskell-doc-mode
add some unused import, e.g. import Data.Char
load file in REPL haskell-process-load-file
when asked to remove redundant import answer y or c
Emacs hangs, triple C-g resumes normal functionality.

Answering n does not lead to hang.

geraldus commented 8 years ago

Ok, folks, I guess I've found the crux of the matter:

Firstly, when you move point at the beginning of import statement haskell-doc-mode shows you a tip import [qualified] modid [as modid] [impspec](which helpfulness is quite questionable).
Secondly, the hang occurs when read-event is called and waiting for keyboard event while haskell-doc-mode produces output to mini-buffer.

To see that everything is works you can increase haskell-doc-idle-delay value, make some changes to force suggestions to take place during next reloading and reload file into REPL, e.g. (setq haskell-doc-idle-delay 30) (for some unknown reason this variable is not customizable), this will give you 30 seconds to press y and import will be removed without hang.

I see only one solution at this moment: turn-off haskell-doc-mode if it is enabled and re-enable it if necessary at the end of execution when haskell-process-load-complete (or even better haskell-process-trigger-suggestions) is running.

haskell-doc-mode looks nice and helpful, but sometimes it is very annoying because all other messages are effectively disappears from mini-buffer when it turned on (though because of this I've discovered presentation mode in past). Maybe it will be better to pop up haskell-doc tips rather than echo them to mini-buffer, but I'm afraid such popups will bring a lot conflicts with other useful packages. Also, I think we need to take a closer look at current doc-mode source, I see a lot of hardcoded stuff there, potentially there are some pieces we can improve, other may be outdated.

By the way, tab-based indentation in haskell-load.el makes code completely unreadable in my Emacs setup. Also, there are a lot of huge function which is hard to follow. This module should be refactored and simplified.

gracjan commented 8 years ago

So haskell-process-load asks modal questions in minibuffer and minibuffer is overwritten?

Short term solution:

haskell-doc-mode needs to suspend showing anything while a modal question is running, that is while haskell-process-trigger-suggestions is running.

Long term solution:

haskell-process-load puts warning overlays in place of code where it can do fixes, fixes are triggered by a key combination.
haskell-doc-mode uses tooltips to show information.

Overall modal questions are bad UI/UX unless caused directly by interactive function or its keybinding.

geraldus commented 8 years ago

Agree, also I always miss the moment when REPL asks me to add/remove something and waiting till spot that question in mini-buffer.

haskell-doc-mode uses tooltips to show information

Do you mean mouse-over tooltips?

@gracjan can you create a well defined task for this? I could take care of this at the end of week if nobody will outrun me.

gracjan commented 8 years ago

I mean same mechanism as flycheck.

Actually I planned to use flycheck as overlay management layer, but current flycheck does not provide that functionality.

gracjan commented 8 years ago

Also see discussion in #754.

geraldus commented 8 years ago

Should we just use this as temporal workaround?

(defun haskell-process-trigger-suggestions-ad (orig-fun &rest args)
  (turn-off-haskell-doc)
  (apply orig-fun args)
  (turn-on-haskell-doc))

(advice-add 'haskell-process-trigger-suggestions
   :around #'haskell-process-trigger-suggestions-ad)

I still didn't catch what you mean by "tooltip"?

geraldus commented 8 years ago

Should be fixed now. Please reopen if still relevant.

anakreontas commented 8 years ago

Thank you.

gracjan commented 8 years ago

@geraldus, I've found much better way to fix this: http://emacs.stackexchange.com/a/20126/5213

Basically (not this-command) ensures that we are free to use minibuffer.

Can you please:

[ ] revert your changes (sorry about that)
[ ] use (not this-command) to safeguard output to minibuffer
[ ] use (not (minibufferp)) to prevent overwriting minibuffer while in minibuffer

Thanks.

geraldus commented 8 years ago

@gracjan hmm, it's ok, but I could delay with this for some time, very short in time now ):

gracjan commented 8 years ago

Or, do nothing about this one :) We will remove haskell-doc-mode soon enough :) Closing in fovor of #1138.

haskell / haskell-mode

haskell-mode becomes unresponsive when adding a language pragma #820

Emacs setting