bug#60830: 30.0.50; The *Compilation* buffer does not recognize Lua errors

["Mattias Engdegård" <mattias.engdegard@gmail.com>]

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6 okt. 2023 kl. 18.49 skrev Stefan Monnier <monnier@iro.umontreal.ca>:

> How 'bout we only activate a handful of rules, and then use a "low
> priority background" search for matches to the non-active rules and when
> we find such a match we bring it to the users' attention that maybe they
> should enable that extra rule?

"It looks like you are compiling a Pascal program using a Sun compiler from 1989. Would you like me to parse the error messages for you?"

Even if we were to pull off the 'low priority background' part, it seems difficult to balance such a mechanism so that it's never annoying yet relevant when it needs to be.

In any case we would benefit from a better way to select rules. One problem is that packages (and users) go wild modifying both CERA and CERAA. Here is a patch that I'm not satisfied with but tries to make CERA easier to customise interactively.

Its main limitation is assuming that explicit rule specs precede symbols that refer to CERAA, which makes some kind of sense (new rules are added for a reason so they should take priority) but may not correspond to reality. Not sure what to do about that, but at least it's a start.


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diff --git a/lisp/progmodes/compile.el b/lisp/progmodes/compile.el
index 9e441dbfcf7..f683859a179 100644
--- a/lisp/progmodes/compile.el
+++ b/lisp/progmodes/compile.el
@@ -748,11 +748,32 @@ compilation-error-regexp-alist
 variable, the `compilation-transform-file-match-alist' variable
 is then consulted.  It allows further transformations of the
 matched file names, and weeding out false positives."
-  :type '(repeat (choice (symbol :tag "Predefined symbol")
-			 (sexp :tag "Error specification")))
+  :type '(list :tag "Rules"
+               (repeat :inline t
+                       :tag "Custom message rules"
+                       (list :tag "Rule specification"
+                             regexp
+                             (sexp :tag "File")
+                             (sexp :tag "Line")
+                             (sexp :tag "Column")
+                             (sexp :tag "Type")
+                             (sexp :tag "Hyperlink")
+                             (repeat :inline t
+                                     :tag "Highlights"
+                                     (list :tag "Highlight"
+                                           (natnum :tag "Submatch")
+                                           (sexp :tag "Face")))))
+               (set :inline t
+                    :tag "Predefined rules"
+                    :convert-widget compilation--predef-rules-widgets))
   :link `(file-link :tag "example file"
 		    ,(expand-file-name "compilation.txt" data-directory)))
 
+(defun compilation--predef-rules-widgets (widget)
+  (widget-put widget :args (mapcar (lambda (x) (list 'const (car x)))
+                                   compilation-error-regexp-alist-alist))
+  widget)
+
 (defvar compilation-error-case-fold-search nil
   "If non-nil, use case-insensitive matching of compilation errors.
 If nil, matching is case-sensitive.