Re: Experimental regexp check: repetition of empty-matching expression

[Mattias Engdegård]

13 apr. 2019 kl. 04.47 skrev Paul Eggert <address@hidden>:
> 
> I think it's useful, except that the last entry (in dabbrev.el) seems to be a 
> false alarm, as a regexp pattern is initially nil but is assigned something 
> else before use, and the trawler assumes it's nil.

Yes, I couldn't make up my mind about the best way to suppress that one. 
Ignoring repetitions of the empty string, like \(?:\)*, may be the answer.

> I installed the attached patch into master to fix the other issues as best I 
> could. Thanks.

That was quick work!

--- a/lisp/mail/mail-extr.el
+++ b/lisp/mail/mail-extr.el
@@ -383,7 +383,7 @@ mail-extr-initial-pattern
 ;; Matches telephone extensions.
 (defconst mail-extr-telephone-extension-pattern
   (purecopy
-   "\\(\\([Ee]xt\\|\\|[Tt]ph\\|[Tt]el\\|[Xx]\\).?\\)? *\\+?[0-9][- 0-9]+"))
+   "\\(\\([Ee]xt\\|[Tt]ph\\|[Tt]el\\|[Xx]\\).?\\)? *\\+?[0-9][- 0-9]+"))
                                             ^
Doesn't it look like the dot is meant to be escaped?
 
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -53,7 +53,7 @@ tramp-adb-method
   "When this method name is used, forward all calls to Android Debug Bridge.")
 
 (defcustom tramp-adb-prompt
-  
"^\\(?:[[:digit:]]*|?\\)?\\(?:[[:alnum:]\e;address@hidden:alnum:]]*[^#\\$]*\\)?[#\\$][[:space:]]"
+  
"^[[:digit:]]*|?\\(?:[[:alnum:]\e;address@hidden:alnum:]]*[^#\\$]*\\)?[#\\$][[:space:]]"
                   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
There is a second one a bit later in the same regexp.