Re^2: Is there an official regex for checking module names? (updated)

> I wouldn't consider the final one valid (even though it was accepted).

It was accepted as package name, ~~but as a module it would hit a wall,~~ ° since :: are translated to path delimiter /

    
  DB<83> use a::::b
Can't locate a//b.pm in @INC
[download]

I'm not sure if there are any file-systems with semantics for an unnamed directory between two '/', win at least gives me a hard time trying to create a directory with an empty string as name.

But I'm wondering if this might have some relevance as vulnerability, since I remember seeing sequences of // as special syntax for network resources.

update

°) It's possible on win at least, because it translates multiple / to no-ops, hence a//b is the same like a/b

so I created

C:\tmp\x\y>echo warn 'inside';1 >z.pm
[download]

started the debugger and ran

  DB<5> use lib '.'

  DB<6> use x::::y::::z
inside at x//y///z.pm line 1.
[download]

It also reveals a trick to force a recompile of a module by adding more :: to the path.

Like that Perl won't find it cached in %INC and try to require it again.

  DB<7> use x::::y::::z

  DB<8> use x::::y::::::z
inside at x//y///z.pm line 1.
 at x//y///z.pm line 1.
[download]

DISCLAIMER: Too lazy to test this with linux (shame on me) and the rest of perlport... (no amiga handy...)

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^3: Is there an official regex for checking module names? by choroba (Cardinal) on Feb 08, 2022 at 23:26 UTC
At least on Linux, for existing modules it works as if just one pair of colons was specified: `main::(-e:1): 1 DB<1> use Time::::Piece;` [download] But it loads the package that's declared in the file under its correct name: `DB<2> x Time::::Piece::localtime->ymd; Can't locate object method "ymd" via package "Time::::Piece::localtime +" (perhaps you forgot to load "Time::::Piece::localtime"?) at (eval 7 +)[/usr/lib/perl5/5.26.1/perl5db.pl:738] line 2. DB<3> x Time::Piece::localtime->ymd; 0 '2022-02-09'` [download] `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l] [select]
Re^4: Is there an official regex for checking module names? by LanX (Saint) on Feb 08, 2022 at 23:29 UTC
Our brains are in sync again, see my update for win... ;-) I'm wondering if there is an OS-agnostic rule to reduce `//` to `/` Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery}	[reply] [d/l] [select]
Re^5: Is there an official regex for checking module names? by ikegami (Patriarch) on Feb 09, 2022 at 00:31 UTC
Not leading ones for Windows. If you include the path portions of URLs, then it might not be safe there either.	[reply]
Re^3: Is there an official regex for checking module names? (updated) by ikegami (Patriarch) on Feb 09, 2022 at 00:27 UTC
I remember seeing sequences of // as special syntax for network resources. In Windows `//` aka `\\` is significant at the start of a path. `\\server\share` `\\localhost\c$` (`C:\`) `\\wsl` `\\server\pipe\name` `\\?\C:\foo` Long path more Too lazy to test this with `linux` `//` is the same as `/` there.	[reply] [d/l] [select]