@code{erc-modules}.
+@anchor{Module Loading}
+@subheading Module Loading
+@cindex module loading
+
+ERC loads internal modules in alphabetical order and third-party
+modules as they appear in @code{erc-modules}. When defining your own
+module, take care to ensure ERC can find it. An easy way to do that
+is by mimicking the example in the doc string for
+@code{define-erc-module}. For historical reasons, ERC also falls back
+to @code{require}ing features. For example, if some module
+@code{<mymod>} in @code{erc-modules} lacks a corresponding
+@code{erc-<mymod>-mode} command, ERC will attempt to load the library
+@code{erc-<mymod>} prior to connecting. If this fails, ERC signals an
+error. Users wanting to define modules in an init files should
+@code{(provide 'erc-<my-mod>)} somewhere to placate ERC. Dynamically
+generating modules on the fly is not supported.
+
+Sometimes, packages attempt to autoload a module's definition instead
+of its minor-mode command, which breaks the link between the library
+and the module. This means that enabling the mode by invoking its
+command toggle isn't enough to load its defining library. Such
+packages should instead only supply autoload cookies featuring an
+explicit @code{autoload} form for their module's minor-mode command.
+As mentioned above, packages can also usually avoid autoload cookies
+entirely so long as their module's prefixed name matches that of its
+defining library and the latter's provided feature.
+
+Packages have also been seen to specify unnecessary top-level
+@code{eval-after-load} forms, which end up being ineffective in most
+cases. Another unfortunate practice is mutating @code{erc-modules}
+itself in an autoloaded form. Doing this tricks Customize into
+displaying the widget for @code{erc-modules} incorrectly, with
+built-in modules moved from the predefined checklist to the
+user-provided free-form area.
+
@c PRE5_4: Document every option of every module in its own subnode
;; each item is in the format '(old . new)
(delete-dups (mapcar #'erc--normalize-module-symbol mods)))
+(defun erc--sort-modules (modules)
+ "Return a copy of MODULES, deduped and led by sorted built-ins."
+ (let (built-in third-party)
+ (dolist (mod modules)
+ (setq mod (erc--normalize-module-symbol mod))
+ (cl-pushnew mod (if (get mod 'erc--module) built-in third-party)))
+ `(,@(sort built-in #'string-lessp) ,@(nreverse third-party))))
+
(defcustom erc-modules '( autojoin button completion fill imenu irccontrols
list match menu move-to-prompt netsplit
networks noncommands readonly ring stamp track)
(when (symbol-value f)
(funcall f 0))
(kill-local-variable f)))))))))
- (let (built-in third-party)
- (dolist (v val)
- (setq v (erc--normalize-module-symbol v))
- (if (get v 'erc--module)
- (push v built-in)
- (push v third-party)))
- ;; Calling `set-default-toplevel-value' complicates testing
- (set sym (append (sort built-in #'string-lessp)
- (nreverse third-party))))
+ ;; Calling `set-default-toplevel-value' complicates testing.
+ (set sym (erc--sort-modules val))
;; this test is for the case where erc hasn't been loaded yet
+ ;; FIXME explain how this ^ can occur or remove comment.
(when (fboundp 'erc-update-modules)
(unless erc--inside-mode-toggle-p
(erc-update-modules))))
(defun erc-update-modules ()
"Enable minor mode for every module in `erc-modules'.
Except ignore all local modules, which were introduced in ERC 5.5."
- (erc--update-modules)
+ (erc--update-modules erc-modules)
nil)
+(defvar erc--aberrant-modules nil
+ "Modules suspected of being improperly loaded.")
+
+(defun erc--warn-about-aberrant-modules ()
+ (when (and erc--aberrant-modules (not erc--target))
+ (erc-button--display-error-notice-with-keys-and-warn
+ "The following modules exhibited strange loading behavior: "
+ (mapconcat (lambda (s) (format "`%s'" s)) erc--aberrant-modules ", ")
+ ". Please contact ERC with \\[erc-bug] if you believe this to be untrue."
+ " See Info:\"(erc) Module Loading\" for more.")
+ (setq erc--aberrant-modules nil)))
+
(defun erc--find-mode (sym)
(setq sym (erc--normalize-module-symbol sym))
- (if-let* ((mode (intern-soft (concat "erc-" (symbol-name sym) "-mode")))
- ((or (boundp mode)
- (and (fboundp mode)
- (autoload-do-load (symbol-function mode) mode)))))
+ (if-let ((mode (intern-soft (concat "erc-" (symbol-name sym) "-mode")))
+ ((and (fboundp mode)
+ (autoload-do-load (symbol-function mode) mode)))
+ ((or (get sym 'erc--module)
+ (symbol-file mode)
+ (ignore (cl-pushnew sym erc--aberrant-modules)))))
mode
(and (require (or (get sym 'erc--feature)
(intern (concat "erc-" (symbol-name sym))))
(fboundp mode)
mode)))
-(defun erc--update-modules ()
+(defun erc--update-modules (modules)
(let (local-modes)
- (dolist (module erc-modules local-modes)
+ (dolist (module modules local-modes)
(if-let ((mode (erc--find-mode module)))
(if (custom-variable-p mode)
(funcall mode 1)
confidently call (erc-foo-mode 1) without having to learn
anything about the dependency's implementation.")
-(defvar erc--setup-buffer-hook nil
+(defvar erc--setup-buffer-hook '(erc--warn-about-aberrant-modules)
"Internal hook for module setup involving windows and frames.")
(defvar erc--display-context nil
(setq old-point (point))
(setq delayed-modules
(erc--merge-local-modes (let ((erc--updating-modules-p t))
- (erc--update-modules))
+ (erc--update-modules
+ (erc--sort-modules erc-modules)))
(or erc--server-reconnecting
erc--target-priors)))
(should (eq (erc--find-group 'smiley nil) 'erc))
(should (eq (erc--find-group 'unmorse nil) 'erc)))
-(ert-deftest erc--update-modules ()
- (let (calls
- erc-modules
- erc-kill-channel-hook erc-kill-server-hook erc-kill-buffer-hook)
+(ert-deftest erc--sort-modules ()
+ (should (equal (erc--sort-modules '(networks foo fill bar fill stamp bar))
+ ;; Third-party mods appear in original order.
+ '(fill networks stamp foo bar))))
+
+(defun erc-tests--update-modules (fn)
+ (let* ((calls nil)
+ (custom-modes nil)
+ (on-load nil)
+
+ (get-calls (lambda () (prog1 (nreverse calls) (setq calls nil))))
+
+ (add-onload (lambda (m k v)
+ (put (intern m) 'erc--feature k)
+ (push (cons k (lambda () (funcall v m))) on-load)))
- ;; This `lbaz' module is unknown, so ERC looks for it via the
- ;; symbol proerty `erc--feature' and, failing that, by
- ;; `require'ing its "erc-" prefixed symbol.
- (should-not (intern-soft "erc-lbaz-mode"))
+ (mk-cmd (lambda (module)
+ (let ((mode (intern (format "erc-%s-mode" module))))
+ (fset mode (lambda (n) (push (cons mode n) calls))))))
+
+ (mk-builtin (lambda (module-string)
+ (let ((s (intern module-string)))
+ (put s 'erc--module s))))
+
+ (mk-global (lambda (module)
+ (push (intern (format "erc-%s-mode" module))
+ custom-modes))))
(cl-letf (((symbol-function 'require)
(lambda (s &rest _)
- (when (eq s 'erc--lbaz-feature)
- (fset (intern "erc-lbaz-mode") ; local module
- (lambda (n) (push (cons 'lbaz n) calls))))
- (push s calls)))
-
- ;; Local modules
- ((symbol-function 'erc-lbar-mode)
- (lambda (n) (push (cons 'lbar n) calls)))
- ((get 'lbaz 'erc--feature) 'erc--lbaz-feature)
-
- ;; Global modules
- ((symbol-function 'erc-gfoo-mode)
- (lambda (n) (push (cons 'gfoo n) calls)))
- ((get 'erc-gfoo-mode 'standard-value) 'ignore)
+ ;; Simulate library being loaded, things defined.
+ (when-let ((h (alist-get s on-load))) (funcall h))
+ (push (cons 'req s) calls)))
+
+ ;; Spoof global module detection.
+ ((symbol-function 'custom-variable-p)
+ (lambda (v) (memq v custom-modes))))
+
+ (funcall fn get-calls add-onload mk-cmd mk-builtin mk-global))
+ (should-not erc--aberrant-modules)))
+
+(ert-deftest erc--update-modules/unknown ()
+ (erc-tests--update-modules
+
+ (lambda (get-calls _ mk-cmd _ mk-global)
+
+ (ert-info ("Baseline")
+ (let* ((erc-modules '(foo))
+ (obarray (obarray-make))
+ (err (should-error (erc--update-modules erc-modules))))
+ (should (equal (cadr err) "`foo' is not a known ERC module"))
+ (should (equal (funcall get-calls)
+ `((req . ,(intern-soft "erc-foo")))))))
+
+ ;; Module's mode command exists but lacks an associated file.
+ (ert-info ("Bad autoload flagged as suspect")
+ (should-not erc--aberrant-modules)
+ (let* ((erc--aberrant-modules nil)
+ (obarray (obarray-make))
+ (erc-modules (list (intern "foo"))))
+
+ ;; Create a mode activation command.
+ (funcall mk-cmd "foo")
+
+ ;; Make the mode var global.
+ (funcall mk-global "foo")
+
+ ;; No local modules to return.
+ (should-not (erc--update-modules erc-modules))
+ (should (equal (mapcar #'prin1-to-string erc--aberrant-modules)
+ '("foo")))
+ ;; ERC requires the library via prefixed module name.
+ (should (equal (mapcar #'prin1-to-string (funcall get-calls))
+ `("(req . erc-foo)" "(erc-foo-mode . 1)"))))))))
+
+;; A local module (here, `lo2') lacks a mode toggle, so ERC tries to
+;; load its defining library, first via the symbol property
+;; `erc--feature', and then via an "erc-" prefixed symbol.
+(ert-deftest erc--update-modules/local ()
+ (erc-tests--update-modules
+
+ (lambda (get-calls add-onload mk-cmd mk-builtin mk-global)
+
+ (let* ((obarray (obarray-make 20))
+ (erc-modules (mapcar #'intern '("glo" "lo1" "lo2"))))
+
+ ;; Create a global and a local module.
+ (mapc mk-cmd '("glo" "lo1"))
+ (mapc mk-builtin '("glo" "lo1"))
+ (funcall mk-global "glo")
+ (funcall add-onload "lo2" 'explicit-feature-lib mk-cmd)
+
+ ;; Returns local modules.
+ (should (equal (mapcar #'symbol-name (erc--update-modules erc-modules))
+ '("erc-lo2-mode" "erc-lo1-mode")))
+
+ ;; Requiring `erc-lo2' defines `erc-lo2-mode'.
+ (should (equal (mapcar #'prin1-to-string (funcall get-calls))
+ `("(erc-glo-mode . 1)"
+ "(req . explicit-feature-lib)")))))))
+
+(ert-deftest erc--update-modules/realistic ()
+ (let ((calls nil)
+ ;; Module `pcomplete' "resolves" to `completion'.
+ (erc-modules '(pcomplete autojoin networks)))
+ (cl-letf (((symbol-function 'require)
+ (lambda (s &rest _) (push (cons 'req s) calls)))
+
+ ;; Spoof global module detection.
+ ((symbol-function 'custom-variable-p)
+ (lambda (v)
+ (memq v '(erc-autojoin-mode erc-networks-mode
+ erc-completion-mode))))
+ ;; Mock and spy real builtins.
((symbol-function 'erc-autojoin-mode)
(lambda (n) (push (cons 'autojoin n) calls)))
- ((get 'erc-autojoin-mode 'standard-value) 'ignore)
((symbol-function 'erc-networks-mode)
(lambda (n) (push (cons 'networks n) calls)))
- ((get 'erc-networks-mode 'standard-value) 'ignore)
((symbol-function 'erc-completion-mode)
- (lambda (n) (push (cons 'completion n) calls)))
- ((get 'erc-completion-mode 'standard-value) 'ignore))
-
- (ert-info ("Unknown module")
- (setq erc-modules '(lfoo))
- (should-error (erc--update-modules))
- (should (equal (pop calls) 'erc-lfoo))
- (should-not calls))
+ (lambda (n) (push (cons 'completion n) calls))))
- (ert-info ("Local modules")
- (setq erc-modules '(gfoo lbar lbaz))
- ;; Don't expose the mode here
- (should (equal (mapcar #'symbol-name (erc--update-modules))
- '("erc-lbaz-mode" "erc-lbar-mode")))
- ;; Lbaz required because unknown.
- (should (equal (nreverse calls) '((gfoo . 1) erc--lbaz-feature)))
- (fmakunbound (intern "erc-lbaz-mode"))
- (unintern (intern "erc-lbaz-mode") obarray)
- (setq calls nil))
-
- (ert-info ("Global modules") ; `pcomplete' resolved to `completion'
- (setq erc-modules '(pcomplete autojoin networks))
- (should-not (erc--update-modules)) ; no locals
- (should (equal (nreverse calls)
- '((completion . 1) (autojoin . 1) (networks . 1))))
- (setq calls nil)))))
+ (should-not (erc--update-modules erc-modules)) ; no locals
+ (should (equal (nreverse calls)
+ '((completion . 1) (autojoin . 1) (networks . 1)))))))
(ert-deftest erc--merge-local-modes ()
(cl-letf (((get 'erc-b-mode 'erc-module) 'b)
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