lisp/emacs-lisp/elint.el

   1 ;;; elint.el --- Lint Emacs Lisp
   2
   3 ;; Copyright (C) 1997, 2001-2014 Free Software Foundation, Inc.
   4
   5 ;; Author: Peter Liljenberg <petli@lysator.liu.se>
   6 ;; Created: May 1997
   7 ;; Keywords: lisp
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software: you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation, either version 3 of the License, or
  14 ;; (at your option) any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  23
  24 ;;; Commentary:
  25
  26 ;; This is a linter for Emacs Lisp.  Currently, it mainly catches
  27 ;; misspellings and undefined variables, although it can also catch
  28 ;; function calls with the wrong number of arguments.
  29
  30 ;; To use, call elint-current-buffer or elint-defun to lint a buffer
  31 ;; or defun.  The first call runs `elint-initialize' to set up some
  32 ;; argument data, which may take a while.
  33
  34 ;; The linter will try to "include" any require'd libraries to find
  35 ;; the variables defined in those.  There is a fair amount of voodoo
  36 ;; involved in this, but it seems to work in normal situations.
  37
  38 ;;; To do:
  39
  40 ;; * Adding type checking. (Stop that sniggering!)
  41 ;; * Make eval-when-compile be sensitive to the difference between
  42 ;;   funcs and macros.
  43 ;; * Requires within function bodies.
  44 ;; * Handle defstruct.
  45 ;; * Prevent recursive requires.
  46
  47 ;;; Code:
  48
  49 (require 'help-fns)
  50
  51 (defgroup elint nil
  52   "Linting for Emacs Lisp."
  53   :prefix "elint-"
  54   :group 'maint)
  55
  56 (defcustom elint-log-buffer "*Elint*"
  57   "The buffer in which to log lint messages."
  58   :type 'string
  59   :safe 'stringp
  60   :group 'elint)
  61
  62 (defcustom elint-scan-preloaded t
  63   "Non-nil means to scan `preloaded-file-list' when initializing.
  64 Otherwise, just scan the DOC file for functions and variables.
  65 This is faster, but less accurate, since it misses undocumented features.
  66 This may result in spurious warnings about unknown functions, etc."
  67   :type 'boolean
  68   :safe 'booleanp
  69   :group 'elint
  70   :version "23.2")
  71
  72 (defcustom elint-ignored-warnings nil
  73   "If non-nil, a list of issue types that Elint should ignore.
  74 This is useful if Elint has trouble understanding your code and
  75 you need to suppress lots of spurious warnings.  The valid list elements
  76 are as follows, and suppress messages about the indicated features:
  77   undefined-functions - calls to unknown functions
  78   unbound-reference   - reference to unknown variables
  79   unbound-assignment  - assignment to unknown variables
  80   macro-expansions    - failure to expand macros
  81   empty-let           - let-bindings with empty variable lists"
  82   :type '(choice (const :tag "Don't suppress any warnings" nil)
  83                  (repeat :tag "List of issues to ignore"
  84                          (choice (const undefined-functions
  85                                         :tag "Calls to unknown functions")
  86                                  (const unbound-reference
  87                                         :tag "Reference to unknown variables")
  88                                  (const unbound-assignment
  89                                         :tag "Assignment to unknown variables")
  90                                  (const macro-expansion
  91                                         :tag "Failure to expand macros")
  92                                  (const empty-let
  93                                         :tag "Let-binding with empty varlist"))))
  94   :safe (lambda (value) (or (null value)
  95                             (and (listp value)
  96                                  (equal value
  97                                         (mapcar
  98                                          (lambda (e)
  99                                            (if (memq e
 100                                                      '(undefined-functions
 101                                                        unbound-reference
 102                                                        unbound-assignment
 103                                                        macro-expansion
 104                                                        empty-let))
 105                                                e))
 106                                          value)))))
 107   :version "23.2"
 108   :group 'elint)
 109
 110 (defcustom elint-directory-skip-re "\\(ldefs-boot\\|loaddefs\\)\\.el\\'"
 111   "If nil, a regexp matching files to skip when linting a directory."
 112   :type '(choice (const :tag "Lint all files" nil)
 113                  (regexp :tag "Regexp to skip"))
 114   :safe 'string-or-null-p
 115   :group 'elint
 116   :version "23.2")
 117
 118 ;;;
 119 ;;; Data
 120 ;;;
 121
 122 (defconst elint-standard-variables
 123   ;; Most of these are defined in C with no documentation.
 124   ;; FIXME I don't see why they shouldn't just get doc-strings.
 125   '(vc-mode local-write-file-hooks activate-menubar-hook buffer-name-history
 126             coding-system-history extended-command-history
 127             yes-or-no-p-history)
 128   "Standard variables, excluding `elint-builtin-variables'.
 129 These are variables that we cannot detect automatically for some reason.")
 130
 131 (defvar elint-builtin-variables nil
 132   "List of built-in variables.  Set by `elint-initialize'.
 133 This is actually all those documented in the DOC file, which includes
 134 built-in variables and those from dumped Lisp files.")
 135
 136 (defvar elint-autoloaded-variables nil
 137   "List of `loaddefs.el' variables.  Set by `elint-initialize'.")
 138
 139 (defvar elint-preloaded-env nil
 140   "Environment defined by the preloaded (dumped) Lisp files.
 141 Set by `elint-initialize', if `elint-scan-preloaded' is non-nil.")
 142
 143 (defconst elint-unknown-builtin-args
 144   ;; encode-time allows extra arguments for use with decode-time.
 145   ;; For some reason, some people seem to like to use them in other cases.
 146   '((encode-time second minute hour day month year &rest zone))
 147   "Those built-ins for which we can't find arguments, if any.")
 148
 149 (defvar elint-extra-errors '(file-locked file-supersession ftp-error)
 150   "Errors without `error-message' or `error-conditions' properties.")
 151
 152 (defconst elint-preloaded-skip-re
 153   (regexp-opt '("loaddefs.el" "loadup.el" "cus-start" "language/"
 154                 "eucjp-ms" "mule-conf" "/characters" "/charprop"
 155                 "cp51932"))
 156   "Regexp matching elements of `preloaded-file-list' to ignore.
 157 We ignore them because they contain no definitions of use to Elint.")
 158
 159 ;;;
 160 ;;; ADT: top-form
 161 ;;;
 162
 163 (defsubst elint-make-top-form (form pos)
 164   "Create a top form.
 165 FORM is the form, and POS is the point where it starts in the buffer."
 166   (cons form pos))
 167
 168 (defsubst elint-top-form-form (top-form)
 169   "Extract the form from a TOP-FORM."
 170   (car top-form))
 171
 172 (defsubst elint-top-form-pos (top-form)
 173   "Extract the position from a TOP-FORM."
 174   (cdr top-form))
 175
 176 ;;;
 177 ;;; ADT: env
 178 ;;;
 179
 180 (defsubst elint-make-env ()
 181   "Create an empty environment."
 182   (list (list nil) nil nil))
 183
 184 (defsubst elint-env-add-env (env newenv)
 185   "Augment ENV with NEWENV.
 186 None of them is modified, and the new env is returned."
 187   (list (append (car env) (car newenv))
 188         (append (cadr env) (cadr newenv))
 189         (append (car (cdr (cdr env))) (car (cdr (cdr newenv))))))
 190
 191 (defsubst elint-env-add-var (env var)
 192   "Augment ENV with the variable VAR.
 193 The new environment is returned, the old is unmodified."
 194   (cons (cons (list var) (car env)) (cdr env)))
 195
 196 (defsubst elint-env-add-global-var (env var)
 197   "Augment ENV with the variable VAR.
 198 ENV is modified so VAR is seen everywhere.
 199 ENV is returned."
 200   (nconc (car env) (list (list var)))
 201   env)
 202
 203 (defsubst elint-env-find-var (env var)
 204   "Non-nil if ENV contains the variable VAR.
 205 Actually, a list with VAR as a single element is returned."
 206   (assq var (car env)))
 207
 208 (defsubst elint-env-add-func (env func args)
 209   "Augment ENV with the function FUNC, which has the arguments ARGS.
 210 The new environment is returned, the old is unmodified."
 211   (list (car env)
 212         (cons (list func args) (cadr env))
 213         (car (cdr (cdr env)))))
 214
 215 (defsubst elint-env-find-func (env func)
 216   "Non-nil if ENV contains the function FUNC.
 217 Actually, a list of (FUNC ARGS) is returned."
 218   (assq func (cadr env)))
 219
 220 (defsubst elint-env-add-macro (env macro def)
 221   "Augment ENV with the macro named MACRO.
 222 DEF is the macro definition (a lambda expression or similar).
 223 The new environment is returned, the old is unmodified."
 224   (list (car env)
 225         (cadr env)
 226         (cons (cons macro def) (car (cdr (cdr env))))))
 227
 228 (defsubst elint-env-macro-env (env)
 229   "Return the macro environment of ENV.
 230 This environment can be passed to `macroexpand'."
 231   (car (cdr (cdr env))))
 232
 233 (defsubst elint-env-macrop (env macro)
 234   "Non-nil if ENV contains MACRO."
 235   (assq macro (elint-env-macro-env env)))
 236
 237 ;;;
 238 ;;; User interface
 239 ;;;
 240
 241 ;;;###autoload
 242 (defun elint-file (file)
 243   "Lint the file FILE."
 244   (interactive "fElint file: ")
 245   (setq file (expand-file-name file))
 246   (or elint-builtin-variables
 247       (elint-initialize))
 248   (let ((dir (file-name-directory file)))
 249     (let ((default-directory dir))
 250       (elint-display-log))
 251     (elint-set-mode-line t)
 252     (with-current-buffer elint-log-buffer
 253       (unless (string-equal default-directory dir)
 254         (elint-log-message (format "\f\nLeaving directory `%s'"
 255                                    default-directory) t)
 256         (elint-log-message (format "Entering directory `%s'" dir) t)
 257         (setq default-directory dir))))
 258   (let ((str (format "Linting file %s" file)))
 259     (message "%s..." str)
 260     (or noninteractive
 261         (elint-log-message (format "\f\n%s at %s" str (current-time-string)) t))
 262     ;; elint-current-buffer clears log.
 263     (with-temp-buffer
 264       (insert-file-contents file)
 265       (let ((buffer-file-name file)
 266             (max-lisp-eval-depth (max 1000 max-lisp-eval-depth)))
 267         (with-syntax-table emacs-lisp-mode-syntax-table
 268           (mapc 'elint-top-form (elint-update-env)))))
 269     (elint-set-mode-line)
 270     (message "%s...done" str)))
 271
 272 ;; cf byte-recompile-directory.
 273 ;;;###autoload
 274 (defun elint-directory (directory)
 275   "Lint all the .el files in DIRECTORY.
 276 A complicated directory may require a lot of memory."
 277   (interactive "DElint directory: ")
 278   (let ((elint-running t))
 279     (dolist (file (directory-files directory t))
 280       ;; Bytecomp has emacs-lisp-file-regexp.
 281       (when (and (string-match "\\.el\\'" file)
 282                  (file-readable-p file)
 283                  (not (auto-save-file-name-p file)))
 284         (if (string-match elint-directory-skip-re file)
 285             (message "Skipping file %s" file)
 286           (elint-file file)))))
 287   (elint-set-mode-line))
 288
 289 ;;;###autoload
 290 (defun elint-current-buffer ()
 291   "Lint the current buffer.
 292 If necessary, this first calls `elint-initialize'."
 293   (interactive)
 294   (or elint-builtin-variables
 295       (elint-initialize))
 296   (elint-clear-log (format "Linting %s" (or (buffer-file-name)
 297                                             (buffer-name))))
 298   (elint-display-log)
 299   (elint-set-mode-line t)
 300   (mapc 'elint-top-form (elint-update-env))
 301   ;; Tell the user we're finished.  This is terribly kludgy: we set
 302     ;; elint-top-form-logged so elint-log-message doesn't print the
 303     ;; ** top form ** header...
 304   (elint-set-mode-line)
 305   (elint-log-message "\nLinting finished.\n" t))
 306
 307
 308 ;;;###autoload
 309 (defun elint-defun ()
 310   "Lint the function at point.
 311 If necessary, this first calls `elint-initialize'."
 312   (interactive)
 313   (or elint-builtin-variables
 314       (elint-initialize))
 315   (save-excursion
 316     (or (beginning-of-defun) (error "Lint what?"))
 317     (let ((pos (point))
 318           (def (read (current-buffer))))
 319       (elint-display-log)
 320       (elint-update-env)
 321       (elint-top-form (elint-make-top-form def pos)))))
 322
 323 ;;;
 324 ;;; Top form functions
 325 ;;;
 326
 327 (defvar elint-buffer-env nil
 328   "The environment of an elisp buffer.
 329 Will be local in linted buffers.")
 330
 331 (defvar elint-buffer-forms nil
 332   "The top forms in a buffer.
 333 Will be local in linted buffers.")
 334
 335 (defvar elint-last-env-time nil
 336   "The last time the buffers env was updated.
 337 Is measured in buffer-modified-ticks and is local in linted buffers.")
 338
 339 ;; This is a minor optimization.  It is local to every buffer, and so
 340 ;; does not prevent recursive requires.  It does not list the requires
 341 ;; of requires.
 342 (defvar elint-features nil
 343   "List of all libraries this buffer has required, or that have been provided.")
 344
 345 (defun elint-update-env ()
 346   "Update the elint environment in the current buffer.
 347 Don't do anything if the buffer hasn't been changed since this
 348 function was called the last time.
 349 Returns the forms."
 350   (if (and (local-variable-p 'elint-buffer-env (current-buffer))
 351            (local-variable-p 'elint-buffer-forms (current-buffer))
 352            (local-variable-p 'elint-last-env-time (current-buffer))
 353            (= (buffer-modified-tick) elint-last-env-time))
 354       ;; Env is up to date
 355       elint-buffer-forms
 356     ;; Remake env
 357     (set (make-local-variable 'elint-buffer-forms) (elint-get-top-forms))
 358     (set (make-local-variable 'elint-features) nil)
 359     (set (make-local-variable 'elint-buffer-env)
 360          (elint-init-env elint-buffer-forms))
 361     (if elint-preloaded-env
 362         ;; FIXME: This doesn't do anything!  Should we setq the result to
 363         ;; elint-buffer-env?
 364         (elint-env-add-env elint-preloaded-env elint-buffer-env))
 365     (set (make-local-variable 'elint-last-env-time) (buffer-modified-tick))
 366     elint-buffer-forms))
 367
 368 (defun elint-get-top-forms ()
 369   "Collect all the top forms in the current buffer."
 370   (save-excursion
 371     (let (tops)
 372       (goto-char (point-min))
 373       (while (elint-find-next-top-form)
 374         (let ((elint-current-pos (point)))
 375           ;; non-list check could be here too. errors may be out of seq.
 376           ;; quoted check cannot be elsewhere, since quotes skipped.
 377           (if (looking-back "'")
 378               ;; Eg cust-print.el uses ' as a comment syntax.
 379               (elint-warning "Skipping quoted form `'%.20s...'"
 380                            (read (current-buffer)))
 381             (condition-case nil
 382                 (setq tops (cons
 383                             (elint-make-top-form (read (current-buffer))
 384                                                  elint-current-pos)
 385                             tops))
 386               (end-of-file
 387                (goto-char elint-current-pos)
 388                (error "Missing ')' in top form: %s"
 389                       (buffer-substring elint-current-pos
 390                                         (line-end-position))))))))
 391       (nreverse tops))))
 392
 393 (defun elint-find-next-top-form ()
 394   "Find the next top form from point.
 395 Return nil if there are no more forms, t otherwise."
 396   (parse-partial-sexp (point) (point-max) nil t)
 397   (not (eobp)))
 398
 399 (defvar elint-env)                      ; from elint-init-env
 400
 401 (defun elint-init-form (form)
 402   "Process FORM, adding to ELINT-ENV if recognized."
 403   (cond
 404    ;; Eg nnmaildir seems to use [] as a form of comment syntax.
 405    ((not (listp form))
 406     (elint-warning "Skipping non-list form `%s'" form))
 407    ;; Add defined variable
 408    ((memq (car form) '(defvar defconst defcustom))
 409     (setq elint-env (elint-env-add-var elint-env (cadr form))))
 410    ;; Add function
 411    ((memq (car form) '(defun defsubst))
 412     (setq elint-env (elint-env-add-func elint-env (cadr form) (nth 2 form))))
 413    ;; FIXME needs a handler to say second arg is not a variable when we come
 414    ;; to scan the form.
 415    ((eq (car form) 'define-derived-mode)
 416     (setq elint-env (elint-env-add-func elint-env (cadr form) ())
 417           elint-env (elint-env-add-var elint-env (cadr form))
 418           elint-env (elint-env-add-var elint-env
 419                                        (intern (format "%s-map" (cadr form))))))
 420    ((eq (car form) 'define-minor-mode)
 421     (setq elint-env (elint-env-add-func elint-env (cadr form) '(&optional arg))
 422           ;; FIXME mode map?
 423           elint-env (elint-env-add-var elint-env (cadr form))))
 424    ((and (eq (car form) 'easy-menu-define)
 425          (cadr form))
 426     (setq elint-env (elint-env-add-func elint-env (cadr form) '(event))
 427           elint-env (elint-env-add-var elint-env (cadr form))))
 428    ;; FIXME it would be nice to check the autoloads are correct.
 429    ((eq (car form) 'autoload)
 430     (setq elint-env (elint-env-add-func elint-env (cadr (cadr form)) 'unknown)))
 431    ((eq (car form) 'declare-function)
 432     (setq elint-env (elint-env-add-func
 433                elint-env (cadr form)
 434                (if (or (< (length form) 4)
 435                        (eq (nth 3 form) t)
 436                        (unless (stringp (nth 2 form))
 437                          (elint-error "Malformed declaration for `%s'"
 438                                       (cadr form))
 439                          t))
 440                    'unknown
 441                  (nth 3 form)))))
 442    ((and (eq (car form) 'defalias) (listp (nth 2 form)))
 443     ;; If the alias points to something already in the environment,
 444     ;; add the alias to the environment with the same arguments.
 445     ;; FIXME symbol-function, eg backquote.el?
 446     (let ((def (elint-env-find-func elint-env (cadr (nth 2 form)))))
 447       (setq elint-env (elint-env-add-func elint-env (cadr (cadr form))
 448                                     (if def (cadr def) 'unknown)))))
 449    ;; Add macro, both as a macro and as a function
 450    ((eq (car form) 'defmacro)
 451     (setq elint-env (elint-env-add-macro elint-env (cadr form)
 452                                    (cons 'lambda (cddr form)))
 453           elint-env (elint-env-add-func elint-env (cadr form) (nth 2 form))))
 454    ((and (eq (car form) 'put)
 455          (= 4 (length form))
 456          (eq (car-safe (cadr form)) 'quote)
 457          (equal (nth 2 form) '(quote error-conditions)))
 458     (set (make-local-variable 'elint-extra-errors)
 459          (cons (cadr (cadr form)) elint-extra-errors)))
 460    ((eq (car form) 'provide)
 461     (add-to-list 'elint-features (eval (cadr form))))
 462    ;; Import variable definitions
 463    ((memq (car form) '(require cc-require cc-require-when-compile))
 464     (let ((name (eval (cadr form)))
 465           (file (eval (nth 2 form)))
 466           (elint-doing-cl (bound-and-true-p elint-doing-cl)))
 467       (unless (memq name elint-features)
 468         (add-to-list 'elint-features name)
 469         ;; cl loads cl-macs in an opaque manner.
 470         ;; Since cl-macs requires cl, we can just process cl-macs.
 471         ;; FIXME: AFAIK, `cl' now behaves properly and does not need any
 472         ;; special treatment any more.  Can someone who understands this
 473         ;; code confirm?  --Stef
 474         (and (eq name 'cl) (not elint-doing-cl)
 475              ;; We need cl if elint-form is to be able to expand cl macros.
 476              (require 'cl)
 477              (setq name 'cl-macs
 478                    file nil
 479                    elint-doing-cl t)) ; blech
 480         (setq elint-env (elint-add-required-env elint-env name file))))))
 481   elint-env)
 482
 483 (defun elint-init-env (forms)
 484   "Initialize the environment from FORMS."
 485   (let ((elint-env (elint-make-env))
 486         form)
 487     (while forms
 488       (setq form (elint-top-form-form (car forms))
 489             forms (cdr forms))
 490       ;; FIXME eval-when-compile should be treated differently (macros).
 491       ;; Could bind something that makes elint-init-form only check
 492       ;; defmacros.
 493       (if (memq (car-safe form)
 494                 '(eval-and-compile eval-when-compile progn prog1 prog2
 495                                    with-no-warnings))
 496           (mapc 'elint-init-form (cdr form))
 497         (elint-init-form form)))
 498     elint-env))
 499
 500 (defun elint-add-required-env (env name file)
 501   "Augment ENV with the variables defined by feature NAME in FILE."
 502   (condition-case err
 503       (let* ((libname (if (stringp file)
 504                           file
 505                         (symbol-name name)))
 506
 507              ;; First try to find .el files, then the raw name
 508              (lib1 (locate-library (concat libname ".el") t))
 509              (lib (or lib1 (locate-library libname t))))
 510         ;; Clear the messages :-/
 511         ;; (Messes up the "Initializing elint..." message.)
 512 ;;;     (message nil)
 513         (if lib
 514             (with-current-buffer (find-file-noselect lib)
 515               ;; FIXME this doesn't use a temp buffer, because it
 516               ;; stores the result in buffer-local variables so that
 517               ;; it can be reused.
 518               (elint-update-env)
 519               (setq env (elint-env-add-env env elint-buffer-env)))
 520               ;;; (with-temp-buffer
 521               ;;;       (insert-file-contents lib)
 522               ;;;       (with-syntax-table emacs-lisp-mode-syntax-table
 523               ;;;         (elint-update-env))
 524               ;;;       (setq env (elint-env-add-env env elint-buffer-env))))
 525               ;;(message "Elint processed (require '%s)" name))
 526           (error "%s.el not found in load-path" libname)))
 527     (error
 528      (message "Can't get variables from require'd library %s: %s"
 529               name (error-message-string err))))
 530   env)
 531
 532 (defvar elint-top-form nil
 533   "The currently linted top form, or nil.")
 534
 535 (defvar elint-top-form-logged nil
 536   "The value t if the currently linted top form has been mentioned in the log buffer.")
 537
 538 (defun elint-top-form (form)
 539   "Lint a top FORM."
 540   (let ((elint-top-form form)
 541         (elint-top-form-logged nil)
 542         (elint-current-pos (elint-top-form-pos form)))
 543     (elint-form (elint-top-form-form form) elint-buffer-env)))
 544
 545 ;;;
 546 ;;; General form linting functions
 547 ;;;
 548
 549 (defconst elint-special-forms
 550   '((let . elint-check-let-form)
 551     (let* . elint-check-let-form)
 552     (setq . elint-check-setq-form)
 553     (quote . elint-check-quote-form)
 554     (function . elint-check-quote-form)
 555     (cond . elint-check-cond-form)
 556     (lambda . elint-check-defun-form)
 557     (function . elint-check-function-form)
 558     (setq-default . elint-check-setq-form)
 559     (defalias . elint-check-defalias-form)
 560     (defun . elint-check-defun-form)
 561     (defsubst . elint-check-defun-form)
 562     (defmacro . elint-check-defun-form)
 563     (defvar . elint-check-defvar-form)
 564     (defconst . elint-check-defvar-form)
 565     (defcustom . elint-check-defcustom-form)
 566     (macro . elint-check-macro-form)
 567     (condition-case . elint-check-condition-case-form)
 568     (if . elint-check-conditional-form)
 569     (when . elint-check-conditional-form)
 570     (unless . elint-check-conditional-form)
 571     (and . elint-check-conditional-form)
 572     (or . elint-check-conditional-form))
 573   "Functions to call when some special form should be linted.")
 574
 575 (defun elint-form (form env &optional nohandler)
 576   "Lint FORM in the environment ENV.
 577 Optional argument NOHANDLER non-nil means ignore `elint-special-forms'.
 578 Returns the environment created by the form."
 579   (cond
 580    ((consp form)
 581     (let ((func (cdr (assq (car form) elint-special-forms))))
 582       (if (and func (not nohandler))
 583           ;; Special form
 584           (funcall func form env)
 585
 586         (let* ((func (car form))
 587                (args (elint-get-args func env))
 588                (argsok t))
 589           (cond
 590            ((eq args 'undefined)
 591             (setq argsok nil)
 592             (or (memq 'undefined-functions elint-ignored-warnings)
 593                 (elint-error "Call to undefined function: %s" func)))
 594
 595            ((eq args 'unknown) nil)
 596
 597            (t (setq argsok (elint-match-args form args))))
 598
 599           ;; Is this a macro?
 600           (if (elint-env-macrop env func)
 601               ;; Macro defined in buffer, expand it
 602               (if argsok
 603                   ;; FIXME error if macro uses macro, eg bytecomp.el.
 604                   (condition-case nil
 605                       (elint-form
 606                        (macroexpand form (elint-env-macro-env env)) env)
 607                     (error
 608                      (or (memq 'macro-expansion elint-ignored-warnings)
 609                          (elint-error "Elint failed to expand macro: %s" func))
 610                      env))
 611                 env)
 612
 613             (let ((fcode (if (symbolp func)
 614                              (if (fboundp func)
 615                                  (indirect-function func))
 616                            func)))
 617               (if (and (listp fcode) (eq (car fcode) 'macro))
 618                   ;; Macro defined outside buffer
 619                   (if argsok
 620                       (elint-form (macroexpand form) env)
 621                     env)
 622                 ;; Function, lint its parameters
 623                 (elint-forms (cdr form) env))))))))
 624    ((symbolp form)
 625     ;; :foo variables are quoted
 626     (and (/= (aref (symbol-name form) 0) ?:)
 627          (not (memq 'unbound-reference elint-ignored-warnings))
 628          (elint-unbound-variable form env)
 629          (elint-warning "Reference to unbound symbol: %s" form))
 630     env)
 631
 632    (t env)))
 633
 634 (defun elint-forms (forms env)
 635   "Lint the FORMS, accumulating an environment, starting with ENV."
 636   ;; grumblegrumbletailrecursiongrumblegrumble
 637   (if (listp forms)
 638       (dolist (f forms env)
 639         (setq env (elint-form f env)))
 640     ;; Loop macro?
 641     (elint-error "Elint failed to parse form: %s" forms)
 642     env))
 643
 644 (defvar elint-bound-variable nil
 645   "Name of a temporarily bound symbol.")
 646
 647 (defun elint-unbound-variable (var env)
 648   "Return t if VAR is unbound in ENV."
 649   ;; #1063 suggests adding (symbol-file var) here, but I don't think
 650   ;; this is right, because it depends on what files you happen to have
 651   ;; loaded at the time, which might not be the same when the code runs.
 652   ;; It also suggests adding:
 653   ;; (numberp (get var 'variable-documentation))
 654   ;; (numberp (cdr-safe (get var 'variable-documentation)))
 655   ;; but this is not needed now elint-scan-doc-file exists.
 656   (not (or (memq var '(nil t))
 657            (eq var elint-bound-variable)
 658            (elint-env-find-var env var)
 659            (memq var elint-builtin-variables)
 660            (memq var elint-autoloaded-variables)
 661            (memq var elint-standard-variables))))
 662
 663 ;;;
 664 ;;; Function argument checking
 665 ;;;
 666
 667 (defun elint-match-args (arglist argpattern)
 668   "Match ARGLIST against ARGPATTERN."
 669   (let ((state 'all)
 670         (al (cdr arglist))
 671         (ap argpattern)
 672         (ok t))
 673     (while
 674         (cond
 675          ((and (null al) (null ap)) nil)
 676          ((eq (car ap) '&optional)
 677           (setq state 'optional)
 678           (setq ap (cdr ap))
 679           t)
 680          ((eq (car ap) '&rest)
 681           nil)
 682          ((or (and (eq state 'all) (or (null al) (null ap)))
 683               (and (eq state 'optional) (and al (null ap))))
 684           (elint-error "Wrong number of args: %s, %s" arglist argpattern)
 685           (setq ok nil)
 686           nil)
 687          ((and (eq state 'optional) (null al))
 688           nil)
 689          (t (setq al (cdr al)
 690                   ap (cdr ap))
 691             t)))
 692     ok))
 693
 694 (defvar elint-bound-function nil
 695   "Name of a temporarily bound function symbol.")
 696
 697 (defun elint-get-args (func env)
 698   "Find the args of FUNC in ENV.
 699 Returns `unknown' if we couldn't find arguments."
 700   (let ((f (elint-env-find-func env func)))
 701     (if f
 702         (cadr f)
 703       (if (symbolp func)
 704           (if (eq func elint-bound-function)
 705               'unknown
 706             (if (fboundp func)
 707                 (let ((fcode (indirect-function func)))
 708                   (if (subrp fcode)
 709                       ;; FIXME builtins with no args have args = nil.
 710                       (or (get func 'elint-args) 'unknown)
 711                     (elint-find-args-in-code fcode)))
 712               'undefined))
 713         (elint-find-args-in-code func)))))
 714
 715 (defun elint-find-args-in-code (code)
 716   "Extract the arguments from CODE.
 717 CODE can be a lambda expression, a macro, or byte-compiled code."
 718   (let ((args (help-function-arglist code)))
 719     (if (listp args) args 'unknown)))
 720
 721 ;;;
 722 ;;; Functions to check some special forms
 723 ;;;
 724
 725 (defun elint-check-cond-form (form env)
 726   "Lint a cond FORM in ENV."
 727   (dolist (f (cdr form))
 728     (if (consp f)
 729         (let ((test (car f)))
 730           (cond ((equal test '(featurep (quote xemacs))))
 731                 ((equal test '(not (featurep (quote emacs)))))
 732                 ;; FIXME (and (boundp 'foo)
 733                 ((and (eq (car-safe test) 'fboundp)
 734                       (= 2 (length test))
 735                       (eq (car-safe (cadr test)) 'quote))
 736                  (let ((elint-bound-function (cadr (cadr test))))
 737                    (elint-forms f env)))
 738                 ((and (eq (car-safe test) 'boundp)
 739                       (= 2 (length test))
 740                       (eq (car-safe (cadr test)) 'quote))
 741                  (let ((elint-bound-variable (cadr (cadr test))))
 742                    (elint-forms f env)))
 743                 (t (elint-forms f env))))
 744       (elint-error "cond clause should be a list: %s" f)))
 745   env)
 746
 747 (defun elint-check-defun-form (form env)
 748   "Lint a defun/defmacro/lambda FORM in ENV."
 749   (setq form (if (eq (car form) 'lambda) (cdr form) (cddr form)))
 750   (mapc (lambda (p)
 751           (or (memq p '(&optional &rest))
 752               (setq env (elint-env-add-var env p))))
 753         (car form))
 754   (elint-forms (cdr form) env))
 755
 756 (defun elint-check-defalias-form (form env)
 757   "Lint a defalias FORM in ENV."
 758   (let ((alias (cadr form))
 759         (target (nth 2 form)))
 760     (and (eq (car-safe alias) 'quote)
 761          (eq (car-safe target) 'quote)
 762          (eq (elint-get-args (cadr target) env) 'undefined)
 763          (elint-warning "Alias `%s' has unknown target `%s'"
 764                         (cadr alias) (cadr target))))
 765   (elint-form form env t))
 766
 767 (defun elint-check-let-form (form env)
 768   "Lint the let/let* FORM in ENV."
 769   (let ((varlist (cadr form)))
 770     (if (not varlist)
 771         (if (> (length form) 2)
 772             ;; An empty varlist is not really an error.  Eg some cl macros
 773             ;; can expand to such a form.
 774             (progn
 775               (or (memq 'empty-let elint-ignored-warnings)
 776                   (elint-warning "Empty varlist in let: %s" form))
 777               ;; Lint the body forms
 778               (elint-forms (cddr form) env))
 779           (elint-error "Malformed let: %s" form)
 780           env)
 781       ;; Check for (let (a (car b)) ...) type of error
 782       (if (and (= (length varlist) 2)
 783                (symbolp (car varlist))
 784                (listp (car (cdr varlist)))
 785                (fboundp (car (car (cdr varlist)))))
 786           (elint-warning "Suspect varlist: %s" form))
 787       ;; Add variables to environment, and check the init values
 788       (let ((newenv env))
 789         (mapc (lambda (s)
 790                 (cond
 791                  ((symbolp s)
 792                   (setq newenv (elint-env-add-var newenv s)))
 793                  ((and (consp s) (<= (length s) 2))
 794                   (elint-form (cadr s)
 795                               (if (eq (car form) 'let)
 796                                   env
 797                                 newenv))
 798                   (setq newenv
 799                         (elint-env-add-var newenv (car s))))
 800                  (t (elint-error
 801                      "Malformed `let' declaration: %s" s))))
 802               varlist)
 803
 804         ;; Lint the body forms
 805         (elint-forms (cddr form) newenv)))))
 806
 807 (defun elint-check-setq-form (form env)
 808   "Lint the setq FORM in ENV."
 809   (or (= (mod (length form) 2) 1)
 810       ;; (setq foo) is valid and equivalent to (setq foo nil).
 811       (elint-warning "Missing value in setq: %s" form))
 812   (let ((newenv env)
 813         sym val)
 814     (setq form (cdr form))
 815     (while form
 816       (setq sym (car form)
 817             val (car (cdr form))
 818             form (cdr (cdr form)))
 819       (if (symbolp sym)
 820           (and (not (memq 'unbound-assignment elint-ignored-warnings))
 821                (elint-unbound-variable sym newenv)
 822                (elint-warning "Setting previously unbound symbol: %s" sym))
 823         (elint-error "Setting non-symbol in setq: %s" sym))
 824       (elint-form val newenv)
 825       (if (symbolp sym)
 826           (setq newenv (elint-env-add-var newenv sym))))
 827     newenv))
 828
 829 (defun elint-check-defvar-form (form env)
 830   "Lint the defvar/defconst FORM in ENV."
 831   (if (or (= (length form) 2)
 832           (= (length form) 3)
 833           ;; Eg the defcalcmodevar macro can expand with a nil doc-string.
 834           (and (= (length form) 4) (string-or-null-p (nth 3 form))))
 835           (elint-env-add-global-var (elint-form (nth 2 form) env)
 836                              (car (cdr form)))
 837     (elint-error "Malformed variable declaration: %s" form)
 838     env))
 839
 840 (defun elint-check-defcustom-form (form env)
 841   "Lint the defcustom FORM in ENV."
 842   (if (and (> (length form) 3)
 843            ;; even no. of keyword/value args ?
 844            (zerop (logand (length form) 1)))
 845       (elint-env-add-global-var (elint-form (nth 2 form) env)
 846                                 (car (cdr form)))
 847     (elint-error "Malformed variable declaration: %s" form)
 848     env))
 849
 850 (defun elint-check-function-form (form env)
 851   "Lint the function FORM in ENV."
 852   (let ((func (car (cdr-safe form))))
 853     (cond
 854      ((symbolp func)
 855       (or (elint-env-find-func env func)
 856           ;; FIXME potentially bogus, since it uses the current
 857           ;; environment rather than a clean one.
 858           (fboundp func)
 859           (elint-warning "Reference to undefined function: %s" form))
 860       env)
 861      ((and (consp func) (memq (car func) '(lambda macro)))
 862       (elint-form func env))
 863      ((stringp func) env)
 864      (t (elint-error "Not a function object: %s" form)
 865         env))))
 866
 867 (defun elint-check-quote-form (form env)
 868   "Lint the quote FORM in ENV."
 869   env)
 870
 871 (defun elint-check-macro-form (form env)
 872   "Check the macro FORM in ENV."
 873   (elint-check-function-form (list (car form) (cdr form)) env))
 874
 875 (defun elint-check-condition-case-form (form env)
 876   "Check the `condition-case' FORM in ENV."
 877   (let ((resenv env))
 878     (if (< (length form) 3)
 879         (elint-error "Malformed condition-case: %s" form)
 880       (or (symbolp (cadr form))
 881           (elint-warning "First parameter should be a symbol: %s" form))
 882       (setq resenv (elint-form (nth 2 form) env))
 883       (let ((newenv (elint-env-add-var env (cadr form)))
 884             errlist)
 885         (dolist (err (nthcdr 3 form))
 886           (setq errlist (car err))
 887           (mapc (lambda (s)
 888                   (or (get s 'error-conditions)
 889                       (get s 'error-message)
 890                       (memq s elint-extra-errors)
 891                       (elint-warning
 892                        "Not an error symbol in error handler: %s" s)))
 893                 (cond
 894                  ((symbolp errlist) (list errlist))
 895                  ((listp errlist) errlist)
 896                  (t (elint-error "Bad error list in error handler: %s"
 897                                  errlist)
 898                     nil)))
 899           (elint-forms (cdr err) newenv))))
 900     resenv))
 901
 902 ;; For the featurep parts, an alternative is to have
 903 ;; elint-get-top-forms skip the irrelevant branches.
 904 (defun elint-check-conditional-form (form env)
 905   "Check the when/unless/and/or FORM in ENV.
 906 Does basic handling of `featurep' tests."
 907   (let ((func (car form))
 908         (test (cadr form))
 909         sym)
 910     ;; Misses things like (and t (featurep 'xemacs))
 911     ;; Check byte-compile-maybe-guarded.
 912     (cond ((and (memq func '(when and))
 913                 (eq (car-safe test) 'boundp)
 914                 (= 2 (length test))
 915                 (eq (car-safe (cadr test)) 'quote))
 916            ;; Cf elint-check-let-form, which modifies the whole ENV.
 917            (let ((elint-bound-variable (cadr (cadr test))))
 918              (elint-form form env t)))
 919           ((and (memq func '(when and))
 920                 (eq (car-safe test) 'fboundp)
 921                 (= 2 (length test))
 922                 (eq (car-safe (cadr test)) 'quote))
 923            (let ((elint-bound-function (cadr (cadr test))))
 924              (elint-form form env t)))
 925           ;; Let's not worry about (if (not (boundp...
 926           ((and (eq func 'if)
 927                 (eq (car-safe test) 'boundp)
 928                 (= 2 (length test))
 929                 (eq (car-safe (cadr test)) 'quote))
 930            (let ((elint-bound-variable (cadr (cadr test))))
 931              (elint-form (nth 2 form) env))
 932            (dolist (f (nthcdr 3 form))
 933              (elint-form f env)))
 934           ((and (eq func 'if)
 935                 (eq (car-safe test) 'fboundp)
 936                 (= 2 (length test))
 937                 (eq (car-safe (cadr test)) 'quote))
 938            (let ((elint-bound-function (cadr (cadr test))))
 939              (elint-form (nth 2 form) env))
 940            (dolist (f (nthcdr 3 form))
 941              (elint-form f env)))
 942           ((and (memq func '(when and)) ; skip all
 943                 (or (null test)
 944                     (member test '((featurep (quote xemacs))
 945                                    (not (featurep (quote emacs)))))
 946                     (and (eq (car-safe test) 'and)
 947                          (equal (car-safe (cdr test))
 948                                 '(featurep (quote xemacs)))))))
 949           ((and (memq func '(unless or))
 950                 (equal test '(featurep (quote emacs)))))
 951           ((and (eq func 'if)
 952                 (or (null test)       ; eg custom-browse-insert-prefix
 953                     (member test '((featurep (quote xemacs))
 954                                    (not (featurep (quote emacs)))))
 955                     (and (eq (car-safe test) 'and)
 956                          (equal (car-safe (cdr test))
 957                                 '(featurep (quote xemacs))))))
 958            (dolist (f (nthcdr 3 form))
 959              (elint-form f env)))       ; lint the else branch
 960           ((and (eq func 'if)
 961                 (equal test '(featurep (quote emacs))))
 962            (elint-form (nth 2 form) env)) ; lint the if branch
 963           ;; Process conditional as normal, without handler.
 964           (t
 965            (elint-form form env t))))
 966   env)
 967
 968 ;;;
 969 ;;; Message functions
 970 ;;;
 971
 972 (defvar elint-current-pos)       ; dynamically bound in elint-top-form
 973
 974 (defun elint-log (type string args)
 975   (elint-log-message (format "%s:%d:%s: %s"
 976                              (let ((f (buffer-file-name)))
 977                                (if f
 978                                    (file-name-nondirectory f)
 979                                  (buffer-name)))
 980                              (if (boundp 'elint-current-pos)
 981                                  (save-excursion
 982                                    (goto-char elint-current-pos)
 983                                    (1+ (count-lines (point-min)
 984                                                     (line-beginning-position))))
 985                                0)       ; unknown position
 986                              type
 987                              (apply 'format string args))))
 988
 989 (defun elint-error (string &rest args)
 990   "Report a linting error.
 991 STRING and ARGS are thrown on `format' to get the message."
 992   (elint-log "Error" string args))
 993
 994 (defun elint-warning (string &rest args)
 995   "Report a linting warning.
 996 See `elint-error'."
 997   (elint-log "Warning" string args))
 998
 999 (defun elint-output (string)
1000   "Print or insert STRING, depending on value of `noninteractive'."
1001   (if noninteractive
1002       (message "%s" string)
1003     (insert string "\n")))
1004
1005 (defun elint-log-message (errstr &optional top)
1006   "Insert ERRSTR last in the lint log buffer.
1007 Optional argument TOP non-nil means pretend `elint-top-form-logged' is non-nil."
1008   (with-current-buffer (elint-get-log-buffer)
1009     (goto-char (point-max))
1010     (let ((inhibit-read-only t))
1011       (or (bolp) (newline))
1012       ;; Do we have to say where we are?
1013       (unless (or elint-top-form-logged top)
1014         (let* ((form (elint-top-form-form elint-top-form))
1015                (top (car form)))
1016           (elint-output (cond
1017                          ((memq top '(defun defsubst))
1018                           (format "\nIn function %s:" (cadr form)))
1019                          ((eq top 'defmacro)
1020                           (format "\nIn macro %s:" (cadr form)))
1021                          ((memq top '(defvar defconst))
1022                           (format "\nIn variable %s:" (cadr form)))
1023                          (t "\nIn top level expression:"))))
1024         (setq elint-top-form-logged t))
1025       (elint-output errstr))))
1026
1027 (defun elint-clear-log (&optional header)
1028   "Clear the lint log buffer.
1029 Insert HEADER followed by a blank line if non-nil."
1030   (let ((dir default-directory))
1031     (with-current-buffer (elint-get-log-buffer)
1032       (setq default-directory dir)
1033       (let ((inhibit-read-only t))
1034         (erase-buffer)
1035         (if header (insert header "\n"))))))
1036
1037 (defun elint-display-log ()
1038   "Display the lint log buffer."
1039   (let ((pop-up-windows t))
1040     (display-buffer (elint-get-log-buffer))
1041     (sit-for 0)))
1042
1043 (defvar elint-running)
1044
1045 (defun elint-set-mode-line (&optional on)
1046   "Set the mode-line-process of the Elint log buffer."
1047   (with-current-buffer (elint-get-log-buffer)
1048     (and (eq major-mode 'compilation-mode)
1049          (setq mode-line-process
1050                (list (if (or on (bound-and-true-p elint-running))
1051                          (propertize ":run" 'face 'compilation-warning)
1052                        (propertize ":finished" 'face 'compilation-info)))))))
1053
1054 (defun elint-get-log-buffer ()
1055   "Return a log buffer for elint."
1056   (or (get-buffer elint-log-buffer)
1057       (with-current-buffer (get-buffer-create elint-log-buffer)
1058         (or (eq major-mode 'compilation-mode)
1059             (compilation-mode))
1060         (setq buffer-undo-list t)
1061         (current-buffer))))
1062
1063 ;;;
1064 ;;; Initializing code
1065 ;;;
1066
1067 (defun elint-put-function-args (func args)
1068   "Mark function FUNC as having argument list ARGS."
1069   (and (symbolp func)
1070        args
1071        (not (eq args 'unknown))
1072        (put func 'elint-args args)))
1073
1074 ;;;###autoload
1075 (defun elint-initialize (&optional reinit)
1076   "Initialize elint.
1077 If elint is already initialized, this does nothing, unless
1078 optional prefix argument REINIT is non-nil."
1079   (interactive "P")
1080   (if (and elint-builtin-variables (not reinit))
1081       (message "Elint is already initialized")
1082     (message "Initializing elint...")
1083     (setq elint-builtin-variables (elint-scan-doc-file)
1084           elint-autoloaded-variables (elint-find-autoloaded-variables))
1085     (mapc (lambda (x) (elint-put-function-args (car x) (cdr x)))
1086           (elint-find-builtin-args))
1087     (if elint-unknown-builtin-args
1088         (mapc (lambda (x) (elint-put-function-args (car x) (cdr x)))
1089               elint-unknown-builtin-args))
1090     (when elint-scan-preloaded
1091       (dolist (lib preloaded-file-list)
1092         ;; Skip files that contain nothing of use to us.
1093         (unless (string-match elint-preloaded-skip-re lib)
1094           (setq elint-preloaded-env
1095                 (elint-add-required-env elint-preloaded-env nil lib)))))
1096     (message "Initializing elint...done")))
1097
1098
1099 ;; This includes all the built-in and dumped things with documentation.
1100 (defun elint-scan-doc-file ()
1101   "Scan the DOC file for function and variables.
1102 Marks the function with their arguments, and returns a list of variables."
1103   ;; Cribbed from help-fns.el.
1104   (let ((docbuf " *DOC*")
1105         vars sym args)
1106     (save-excursion
1107       (if (get-buffer docbuf)
1108           (progn
1109             (set-buffer docbuf)
1110             (goto-char (point-min)))
1111         (set-buffer (get-buffer-create docbuf))
1112         (insert-file-contents-literally
1113          (expand-file-name internal-doc-file-name doc-directory)))
1114       (while (re-search-forward "\x1f\\([VF]\\)" nil t)
1115         (when (setq sym (intern-soft (buffer-substring (point)
1116                                                        (line-end-position))))
1117           (if (string-equal (match-string 1) "V")
1118               ;; Excludes platform-specific stuff not relevant to the
1119               ;; running platform.
1120               (if (boundp sym) (setq vars (cons sym vars)))
1121             ;; Function.
1122             (when (fboundp sym)
1123               (when (re-search-forward "\\(^(fn.*)\\)?\x1f" nil t)
1124                 (backward-char 1)
1125                 ;; FIXME distinguish no args from not found.
1126                 (and (setq args (match-string 1))
1127                      (setq args
1128                            (ignore-errors
1129                              (read
1130                               (replace-regexp-in-string "^(fn ?" "(" args))))
1131                      (elint-put-function-args sym args))))))))
1132     vars))
1133
1134 (defun elint-find-autoloaded-variables ()
1135   "Return a list of all autoloaded variables."
1136   (let (var vars)
1137     (with-temp-buffer
1138       (insert-file-contents (locate-library "loaddefs.el"))
1139       (while (re-search-forward "^(defvar \\([[:alnum:]_-]+\\)" nil t)
1140         (and (setq var (intern-soft (match-string 1)))
1141              (boundp var)
1142              (setq vars (cons var vars)))))
1143     vars))
1144
1145 (defun elint-find-builtins ()
1146   "Return a list of all built-in functions."
1147   (let (subrs)
1148     (mapatoms (lambda (s) (and (subrp (symbol-function s))
1149                           (push s subrs))))
1150     subrs))
1151
1152 (defun elint-find-builtin-args (&optional list)
1153   "Return a list of the built-in functions and their arguments.
1154 If LIST is nil, call `elint-find-builtins' to get a list of all built-in
1155 functions, otherwise use LIST.
1156
1157 Each function is represented by a cons cell:
1158 \(function-symbol . args)
1159 If no documentation could be found args will be `unknown'."
1160   (mapcar (lambda (f)
1161             (let ((doc (documentation f t)))
1162               (or (and doc
1163                        (string-match "\n\n(fn\\(.*)\\)\\'" doc)
1164                        (ignore-errors
1165                         ;; "BODY...)" -> "&rest BODY)".
1166                         (read (replace-regexp-in-string
1167                                "\\([^ ]+\\)\\.\\.\\.)\\'" "&rest \\1)"
1168                                (format "(%s %s" f (match-string 1 doc)) t))))
1169                   (cons f 'unknown))))
1170           (or list (elint-find-builtins))))
1171
1172 (provide 'elint)
1173
1174 ;;; elint.el ends here