strange constants.pm warning

misterperl has asked for the wisdom of the Perl Monks concerning the following question:

...using constants.pm 1.04, I keep hitting this in the else: "Constant name '$name' has unknown problems" , which can only happen if:

 if ($name =~ /^_?[^\W_0-9]\w*\z/ and !$forbidden{$name}) {
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is false. So, I set a break like this:

<DBG>b 52 $name !~ /^_?[^\W_0-9]\w*\z/
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and sure enough, it broke there. (My name is simple, DB_ERROR.) That's when things got weird, at the break, I tried:

<DBG>x $name =~ /^_?[^\W_0-9]\w*\z/
1
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  DB<4> x $name !~ /^_?[^\W_0-9]\w*\z/
0  ''
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..another mystery, how the HECK DID IT break there? I tried:

<DBG>b 52 ! $name =~ /^_?[^\W_0-9]\w*\z/
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which looks logically the same as <code> $name !~ /^_?^\W_0-9\w*\z/ <code> but, now more weirdness, it no longer breaks there.

My spyder sense tells me this is due to some pragma/debugger weirdness, since I'm breaking in the pragma. But the issue is there is nothing wrong with my use statement, yet it throws that unknown error warning, and I was trying to see why.

Wisdom please?

Comment on strange constants.pm warning Select or Download Code

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Re: strange constants.pm warning by Perlbotics (Archbishop) on Aug 30, 2021 at 17:57 UTC
How do you init `$name`? Like `use constant name => 42`? Then `if ( name =~ /^_?[^\W_0-9]\w*\z/ and !$forbidden{ name() }) {` [download] might work? Conststant creates a sub witht the given name that returns the value.	[reply] [d/l] [select]
Re^2: strange constants.pm warning by misterperl (Pilgrim) on Aug 30, 2021 at 18:02 UTC
`use constant DB_ERROR => "database error";` [download]	[reply] [d/l]
Re^2: strange constants.pm warning by misterperl (Pilgrim) on Aug 30, 2021 at 18:11 UTC
I haven't tried to see if the sub actually gets created- Im just trying to figure out why this valid statement throws this unknown warning message.. AND to find out why the debuger break where apparently it shouldn't..	[reply]
Re^3: strange constants.pm warning by Perlbotics (Archbishop) on Aug 30, 2021 at 18:34 UTC
Okay, misunderstanding. I thought this happens in your code but it is actually a line from the `import()` sub of constant. `} else { # Catch-all - what did I miss? If you get this err +or, # please let me know what your constant's name was +. # Write to <rootbeer@redcat.com>. Thanks! warnings::warn("Constant name '$name' has unknown +problems"); }` [download] Your example works here. Perhaps some non-printable characters have sneaked in to your text file or there is a clash (other module or within your code) that uses the same constant? What happens if you change DB_ERROR to MY_DB_ERROR? No better ideas ATM, sorry.	[reply] [d/l] [select]
Re^4: strange constants.pm warning by misterperl (Pilgrim) on Aug 31, 2021 at 18:16 UTC
Re^5: strange constants.pm warning by tobyink (Canon) on Sep 03, 2021 at 11:38 UTC
Re: strange constants.pm warning by misterperl (Pilgrim) on Sep 01, 2021 at 12:56 UTC
the sysadmin got us on v1.33 and no more warnings! TY for the comments guys. I'm still perplexed as to why the debugger broke on a false statement. Cheers!	[reply]
Re^2: strange constant.pm warning by hippo (Bishop) on Sep 01, 2021 at 13:42 UTC
the sysadmin got us on v1.33 I've just re-read your OP and noticed that you said you were using v1.04. That's more than 20 years old! It is rather impressive that you have been using it solidly for so long and only just now hit a problem. Anyway, glad the upgrade has fixed it for you. Perhaps maybe consider an audit of other key modules in use on your systems with a few to further upgrades? ;-) 🦛	[reply]
Re^3: strange constant.pm warning by misterperl (Pilgrim) on Sep 02, 2021 at 15:21 UTC
actually - not me, my client is. They keep cloning old boxes and we end up with stuff like this sometimes. Thanks for the observation I had no idea it was THAT old! I'd love to do a CPAN update on all but the client only allows them selectively.	[reply]
Re: strange constants.pm warning by Anonymous Monk on Aug 31, 2021 at 15:19 UTC
I take it from previous comments that you mean constant.pm, not `constants.pm`, which I can not find in Metacpan. According to `corelist`, `constant 1.04` shipped with Perl 5.7.3. Metacpan does not list this version even on Backpan. If this is right, wisdom may be hard to come by.	[reply] [d/l] [select]
Re^2: strange constants.pm warning by misterperl (Pilgrim) on Aug 31, 2021 at 18:03 UTC
yes my inattention to detail - constant.pm	[reply]
Re^3: strange constants.pm warning by misterperl (Pilgrim) on Aug 31, 2021 at 18:09 UTC
I did request that the node admin update the constant.pm module. That may also solve this. TYVM	[reply]


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