X-Git-Url: https://code.delx.au/gnu-emacs-elpa/blobdiff_plain/233abf8df3d0750692f5edea2a0f1fb4b7746a29..addec68b2d8490523dfffd04be8997d8b1840303:/packages/bug-hunter/bug-hunter.el diff --git a/packages/bug-hunter/bug-hunter.el b/packages/bug-hunter/bug-hunter.el new file mode 100644 index 000000000..bd6c06da3 --- /dev/null +++ b/packages/bug-hunter/bug-hunter.el @@ -0,0 +1,424 @@ +;;; bug-hunter.el --- Hunt down errors in elisp files -*- lexical-binding: t; -*- + +;; Copyright (C) 2015 Free Software Foundation, Inc. + +;; Author: Artur Malabarba +;; URL: http://github.com/Bruce-Connor/elisp-bug-hunter +;; Version: 0.1 +;; Keywords: lisp +;; Package-Requires: ((seq "1.3") (cl-lib "0.5")) + +;; This program is free software; you can redistribute it and/or modify +;; it under the terms of the GNU General Public License as published by +;; the Free Software Foundation, either version 3 of the License, or +;; (at your option) any later version. +;; +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +;; GNU General Public License for more details. +;; +;; You should have received a copy of the GNU General Public License +;; along with this program. If not, see . + +;;; Commentary: +;; `bug-hunter' is an Emacs library that finds the source of an error or +;; unexpected behavior inside an elisp configuration file (tipically +;; `init.el' or `.emacs'). +;; +;; +;; Usage Examples +;; ============== +;; +;; If your Emacs init file signals an error during startup, but you don’t +;; know why, simply issue +;; ,---- +;; | M-x bug-hunter-init-file RET RET +;; `---- +;; and `bug-hunter' will find it for you. +;; +;; If Emacs starts up without errors but something is not working as it +;; should, invoke the same command, but give it in an assertion. +;; Essentially, if you can write a snippet that detects the issue and +;; returns non-nil, just provide this snippet as the assertion and the +;; Bug Hunter will do a bisection search for you. +;; +;; For example, let’s say there’s something in your init file that’s +;; loading the `cl' library, and you don’t want that. You /know/ you’re +;; not loading it yourself, but how can you figure out which external +;; package is responsible for this outrage? +;; +;; ,---- +;; | M-x bug-hunter-init-file RET (featurep 'cl) RET +;; `---- +;; +;; *That’s it!* You’ll be given a nice buffer reporting the results: +;; +;; - Are you getting obscure errors when trying to open /“.tex”/ files? +;; Don’t despair! Just use `(find-file "dummy.tex")' as the assertion. +;; - Did `ox-html' stop working due to some arcane misconfiguration? Just +;; write an assertion that does an export and checks the result. +;; - Does some random command suddenly bind itself to `C-j' and you can’t +;; figure out why? `(eq (key-binding "\n") 'unwanted-command)' is the +;; assertion for you! +;; +;; Finally, you can also use `bug-hunter-file' to hunt in other files. +;; + +;; Installation +;; ============ +;; +;; Bug Hunter will be on Gelpa shortly. For now, do the following: +;; 1. Open the `bug-hunter.el` file. +;; 2. Issue `M-x package-install-from-buffer`. + + +;;; Code: +(require 'seq) +(require 'cl-lib) + +(defvar bug-hunter--assertion-reminder + "Remember, the assertion must be an expression that returns +non-nil in your current (problematic) Emacs state, AND that +returns nil on a clean Emacs instance." + "Printed to the user if they provide a bad assertion.") + +(defvar bug-hunter--current-head nil + "Current list of expressions under scrutiny. Used for user feedback. +Used if the user aborts before bisection ends.") + +(defvar bug-hunter--i 0 + "Current step of the bisection. Used for user feedback.") +(defvar bug-hunter--estimate 0 + "Estimate on how many steps the bisection can take. Used for user feedback. +This is the base 2 log of the number of expressions in the +file.") + +(defvar bug-hunter--current-file nil + "File currently being debugged.") + +(defun bug-hunter--read-buffer () + "Return all sexps after point as a list." + (let (out line col) + (or (condition-case er + ;; Looks hacky, but comes from `byte-compile-from-buffer'. + (while (progn (while (progn (skip-chars-forward " \t\n\^l") + (looking-at ";")) + (forward-line 1)) + (not (eobp))) + (setq line (line-number-at-pos (point))) + (setq col (current-column)) + (push (list (read (current-buffer)) line col) + out) + nil) + (end-of-file `(bug-caught (end-of-file) ,line ,col)) + (invalid-read-syntax `(bug-caught ,er ,line ,col)) + (error (error "Ran into an error we don't understand, please file a bug report: %S" er))) + (nreverse out)))) + +(defun bug-hunter--read-contents (file) + "Return all sexps in FILE as a list." + (with-temp-buffer + (insert-file-contents file) + (goto-char (point-min)) + (bug-hunter--read-buffer))) + + +;;; Reporting functions +(defun bug-hunter--report-print (&rest r) + "Print information on the \"*Bug-Hunter Report*\" buffer. +R is passed to `format' and inserted." + (with-current-buffer (get-buffer-create "*Bug-Hunter Report*") + (goto-char (point-max)) + (let ((inhibit-read-only t)) + (insert "\n" (apply #'format r))))) + +(defun bug-hunter--report (&rest r) + "Report arbitrary information. +R is passed to `bug-hunter--report-print'." + (declare (indent 1)) + (apply #'bug-hunter--report-print r) + (apply #'message r)) + +(defun bug-hunter--report-user-error (&rest r) + "Report the user has done something wrong. +R is passed to `bug-hunter--report-print'." + (declare (indent 1)) + (apply #'bug-hunter--report-print r) + (bug-hunter--report-print "\xc") + (apply #'user-error r)) + +(defvar compilation-error-regexp-alist) +(defun bug-hunter--init-report-buffer () + "Create and prepare the \"*Bug-Hunter Report*\" buffer." + (or (get-buffer "*Bug-Hunter Report*") + (with-current-buffer (get-buffer-create "*Bug-Hunter Report*") + (compilation-mode "Bug Hunt") + (set (make-local-variable 'compilation-error-regexp-alist) + '(comma)) + (current-buffer)))) + +(defun bug-hunter--pretty-format (value padding) + "Return a VALUE as a string with PADDING spaces on the left." + (with-temp-buffer + (pp value (current-buffer)) + (goto-char (point-min)) + (let ((pad (make-string padding ?\s))) + (while (not (eobp)) + (insert pad) + (forward-line 1))) + (buffer-string))) + +(defun bug-hunter--report-error (error line column &optional expression) + "Print on report buffer information about ERROR. +LINE and COLUMN are the coordinates where EXPRESSION started in +the file." + (when line + (bug-hunter--report "%S, line %s pos %s:" + bug-hunter--current-file line column)) + (bug-hunter--report " %s" + (cl-case (car error) + (end-of-file + "There's a missing closing parenthesis, the expression on this line never ends.") + (invalid-read-syntax + (let ((char (cadr error))) + (if (member char '("]" ")")) + (concat "There's an extra " char + " on this position. There's probably a missing " + (if (string= char ")") "(" "[") + " before that.") + (concat "There's a " char + " on this position, and that is not valid elisp syntax.")))) + (user-aborted + (let* ((print-level 2) + (print-length 15) + (forms (cadr error)) + (size (length forms))) + (concat "User aborted while testing the following expressions:\n" + (mapconcat (lambda (x) (bug-hunter--pretty-format x 4)) + (if (< size 16) forms (seq-take forms 7)) + "") + (when (> size 16) + (format "\n ... %s omitted expressions ...\n\n" + (- size 14))) + (when (> size 16) + (mapconcat (lambda (x) (bug-hunter--pretty-format x 4)) + (seq-drop forms (- size 7)) ""))))) + (assertion-triggered + (concat "The assertion returned the following value here:\n" + (bug-hunter--pretty-format (cadr error) 4))) + (t (format "The following error was signaled here:\n %S" + error)))) + (when expression + (bug-hunter--report " Caused by the following expression:\n%s" + (bug-hunter--pretty-format expression 4))) + (bug-hunter--report "\xc") + `[,error ,line ,column ,expression]) + + +;;; Execution functions +(defun bug-hunter--run-form (form) + "Run FORM with \"emacs -Q\" and return the result." + (let ((out-buf (generate-new-buffer "*Bug-Hunter Command*")) + (exec (file-truename (expand-file-name invocation-name + invocation-directory))) + (file-name (make-temp-file "bug-hunter"))) + (unwind-protect + (let ((print-length nil) + (print-level nil)) + (with-temp-file file-name + (print (list 'prin1 form) (current-buffer))) + (call-process exec nil out-buf nil + "-Q" "--batch" "-l" + (shell-quote-argument file-name)) + (with-current-buffer out-buf + (goto-char (point-max)) + (forward-sexp -1) + (prog1 (read (current-buffer)) + (kill-buffer (current-buffer))))) + (delete-file file-name)))) + +(defun bug-hunter--run-and-test (forms assertion) + "Execute FORMS in the background and test ASSERTION. +See `bug-hunter' for a description on the ASSERTION." + (bug-hunter--run-form + `(condition-case er + (let ((server-name (make-temp-file "bug-hunter-temp-server-file"))) + (delete-file server-name) + ,@forms + (run-hooks 'after-init-hook) + ,assertion) + (error (cons 'bug-caught er))))) + + + +;;; The actual bisection +(defun bug-hunter--split (l) + "Split list L in two lists of same size." + (seq-partition l (ceiling (/ (length l) 2.0)))) + +(defun bug-hunter--bisect (assertion safe head &optional tail) + "Implementation used by `bug-hunter--bisect-start'. +ASSERTION is received by `bug-hunter--bisect-start'. +SAFE is a list of forms confirmed to not match the ASSERTION, +HEAD is a list of forms to be tested now, and TAIL is a list +which will be inspected if HEAD doesn't match ASSERTION." + (cond + ((not tail) + (vector (length safe) + ;; Sometimes we already ran this, sometimes not. So it's + ;; easier to just run it anyway to get the return value. + (bug-hunter--run-and-test (append safe head) assertion))) + ((and (message "Testing: %s/%s" + (cl-incf bug-hunter--i) + bug-hunter--estimate) + (setq bug-hunter--current-head head) + (bug-hunter--run-and-test (append safe head) assertion)) + (apply #'bug-hunter--bisect + assertion + safe + (bug-hunter--split head))) + (t (apply #'bug-hunter--bisect + assertion + (append safe head) + (bug-hunter--split tail))))) + +(defun bug-hunter--bisect-start (forms assertion) + "Run a bisection search on list of FORMS using ASSERTION. +Returns a vector [n value], where n is the position of the first +element in FORMS which trigger ASSERTION, and value is the +ASSERTION's return value. + +If ASSERTION is nil, n is the position of the first form to +signal an error and value is (bug-caught . ERROR-SIGNALED)." + (let ((bug-hunter--i 0) + (bug-hunter--estimate (ceiling (log (length forms) 2))) + (bug-hunter--current-head nil)) + (condition-case-unless-debug nil + (apply #'bug-hunter--bisect assertion nil (bug-hunter--split forms)) + (quit `[nil (bug-caught user-aborted ,bug-hunter--current-head)])))) + + +;;; Main functions +(defun bug-hunter-hunt (rich-forms assertion) + "Bisect RICH-FORMS using ASSERTION. +RICH-FORMS is a list with elements of the form: (EXPR LINE COL) + EXPR is an elisp expression. LINE and COL are the coordinates + in `bug-hunter--current-file' where the expression starts. +It is expected that one of EXPR is either throwing an error or +causing some undesirable effect (which triggers ASSERTION). + +ASSERTION is either nil or an expression. + If nil, EXPRs are bisected until we find the first one that + throws errors. + If it is an expression, EXPRs are bisected by testing + ASSERTION. It should return nil if all is fine (e.g. if used + with \"emacs -Q\"), and should return non-nil when a problem + is detected. + +Bug hunter will refuse to hunt if (i) an error is signaled or the +assertion is triggered while running emacs -Q, or (ii) no errors +are signaled and the assertion is not triggered after all EXPRs +are evaluated." + (pop-to-buffer (bug-hunter--init-report-buffer)) + (let ((expressions (unless (eq (car-safe rich-forms) 'bug-caught) + (mapcar #'car rich-forms)))) + (cond + ((not expressions) + (apply #'bug-hunter--report-error (cdr rich-forms)) + (apply #'vector (cdr rich-forms))) + + ;; Make sure there's a bug to hunt. + ((progn (bug-hunter--report "Doing some initial tests...") + (not (bug-hunter--run-and-test expressions assertion))) + (bug-hunter--report-user-error "Test failed.\n%s\n%s" + (if assertion + (concat "The assertion returned nil after loading the entire file.\n" + bug-hunter--assertion-reminder) + "No errors signaled after loading the entire file. If you're +looking for something that's not an error, you need to provide an +assertion. See this link for some examples: + https://github.com/Bruce-Connor/elisp-bug-hunter") + (or assertion ""))) + + ;; Make sure we're in a forest, not a volcano. + ((bug-hunter--run-and-test nil assertion) + (bug-hunter--report-user-error "Test failed.\n%s\n%s" + (if assertion + (concat "Assertion returned non-nil even on emacs -Q:" + bug-hunter--assertion-reminder) + "Detected a signaled error even on emacs -Q. I'm sorry, but there +is something seriously wrong with your Emacs installation. +There's nothing more I can do here.") + (or assertion ""))) + + (t + ;; Perform the actual hunt. + (bug-hunter--report "Initial tests done. Hunting for the cause...") + (let* ((result (bug-hunter--bisect-start expressions assertion))) + (if (not result) + (bug-hunter--report-user-error "No problem was found, despite our initial tests.\n%s" + "I have no idea what's going on.") + (let* ((pos (elt result 0)) + (ret (elt result 1)) + (linecol (when pos (cdr (elt rich-forms pos)))) + (expression (when pos (elt expressions pos)))) + (if (eq (car-safe ret) 'bug-caught) + (bug-hunter--report-error + (cdr ret) (car linecol) (cadr linecol) expression) + (bug-hunter--report-error + (list 'assertion-triggered ret) + (car linecol) (cadr linecol) expression))))))))) + +(defun bug-hunter--read-from-minibuffer () + "Read a list of expressions from the minibuffer. +Wraps them in a progn if necessary." + (require 'simple) + (let ((exprs + (with-temp-buffer + ;; Copied from `read--expression'. + (let ((minibuffer-completing-symbol t)) + (minibuffer-with-setup-hook + (lambda () + ;; FIXME: call emacs-lisp-mode? + (add-function :before-until (local 'eldoc-documentation-function) + #'elisp-eldoc-documentation-function) + (add-hook 'completion-at-point-functions + #'elisp-completion-at-point nil t) + (run-hooks 'eval-expression-minibuffer-setup-hook)) + (insert + (read-from-minibuffer + "Expression that returns nil if all is well (optional): " + nil read-expression-map nil 'read-expression-history)))) + (goto-char (point-min)) + (mapcar #'car (bug-hunter--read-buffer))))) + (if (cdr exprs) + (cons #'progn exprs) + (car exprs)))) + +;;;###autoload +(defun bug-hunter-file (file &optional assertion) + "Bisect FILE while testing ASSERTION. +All sexps in FILE are read and passed to `bug-hunter-hunt' as a +list. See `bug-hunter-hunt' for how to use assertion." + (interactive + (list + (read-file-name "File to bisect: " + (file-name-directory (or (buffer-file-name) "./")) + nil t + (file-name-nondirectory (or (buffer-file-name) "./"))) + (bug-hunter--read-from-minibuffer))) + (let ((bug-hunter--current-file file)) + (bug-hunter-hunt (bug-hunter--read-contents file) assertion))) + +;;;###autoload +(defun bug-hunter-init-file (&optional assertion) + "Test ASSERTION throughout `user-init-file'. +All sexps inside `user-init-file' are read and passed to +`bug-hunter-hunt' as a list. See `bug-hunter-hunt' for how to use +assertion." + (interactive (list (bug-hunter--read-from-minibuffer))) + (bug-hunter-file user-init-file assertion)) + +(provide 'bug-hunter) +;;; bug-hunter.el ends here