Module name case typo silent failure

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

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Re: Module name case typo silent failure by Corion (Patriarch) on Sep 19, 2019 at 19:36 UTC
Perl modules/package names and the names of the files they are stored in don't need to match. And if no `import` method exists, use will not complain.	[reply] [d/l]
Re: Module name case typo silent failure by LanX (Saint) on Sep 19, 2019 at 20:09 UTC
It depends on the operating system or resp. file system. Your code creates a fatal error on Linux but (after adaption°) runs on Windows because the standard FS there is case-insensitive Linux: `perl -MTime::Hires=time -Wle 'print time' Can't locate Time/Hires.pm in @INC` [download] Windows: `C:\WINDOWS\system32>perl -MTime::Hires=time -Wle "print time" 1568923613` [download] `use` is a require + import at compile time `BEGIN { require Module; Module->import( LIST ); }` That is it does a `require` of `Time::HiRes` (case-insensitive finds `Hires.pm` ) but fails to call `Time::Hires->import()` (Perl is case-sensitive) Corion already explained that a missing `->import` method doesn't create an error, and the typo'ed Module = package = `Time::Hires` has no `->import` routine. One might argue that the non-existence of the package `Time::Hires` should raise an error, probably you should file an error with perlbug. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice} °) QUESTION: Where did you test that code???	[reply] [d/l] [select]
Re^2: Module name case typo silent failure by AnomalousMonk (Archbishop) on Sep 19, 2019 at 20:29 UTC
... file an error with perlbug. Having a case-preserving but case-insensitive file system is another wonderful feature of Windows. Perl tries to be OS-agnostic, but there's only so much a humble program can do. The fact that this problem has not been addressed so far suggests to me that it's very difficult or impossible to deal with in this particular OS. Can you think of a way? Give a man a fish: `<%-{-{-{-<`	[reply] [d/l]
Re^3: Module name case typo silent failure by LanX (Saint) on Sep 19, 2019 at 20:53 UTC
> Can you think of a way? IMHO the problem is at another place. It's OK that ->import() is not required to exist inside a package (or let's say I doubt that this can be changed in a backwards compatible way). But trying to call a method on a non-existing package could fail. I.e. `use` could check if the MODULE-name exists in the right capitalization after require.* But for reasons that I do not understand yet does require auto-vivify the misspelled package. `DB<7> require DaTa::DuMpEr DB<8> x grep {/dumper/i} %DaTa:: 0 'DuMpEr::' 1 DaTa::DuMpEr:: DB<9>` [download] Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice} ) or if it exists twice in different capitalizations.	[reply] [d/l]
Re^2: Module name case typo silent failure by LanX (Saint) on Sep 19, 2019 at 20:37 UTC
> One might argue that the non-existence of the package `Time::Hires` should raise an error, probably you should file an error with perlbug. not sure what is happening there, something creates the wrong namespace `%Time::Hires::` after a `require` `DB<1> x grep {/hires/i} %Time:: empty array DB<2> require Time::Hires DB<3> x grep {/hires/i} %Time:: 0 'HiRes::' 1 Time::HiRes:: 2 'Hires::' 3 Time::Hires:: DB<4>` [download] Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}	[reply] [d/l] [select]
Re^3: Module name case typo silent failure by Haarg (Priest) on Sep 19, 2019 at 22:53 UTC
The stash is created when parsing the require function. It doesn't even have to be run. This generally doesn't matter but can have an impact on things like indirect method calls. Existence of a stash isn't really a useful concept though. Too many things can lead to a stash existing, including loading a sub-package (loading `Blurf::Guff` would cause the `Blurf::` stash to exist).	[reply] [d/l] [select]
Re^4: Module name case typo silent failure by LanX (Saint) on Sep 19, 2019 at 23:04 UTC
Re^2: Module name case typo silent failure by Anonymous Monk on Sep 19, 2019 at 21:17 UTC
Where did you test that code??? perl -MConfig -le'print join" ",$],$^O,$Config{osvers}' 5.028000 darwin 17.5.0 Thank you for the thorough explanation.	[reply]
Re^3: Module name case typo silent failure by LanX (Saint) on Sep 19, 2019 at 21:31 UTC
> 5.028000 darwin 17.5.0 your FS must be case-insensitive then (?) > Thank you Your welcome! :) Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}	[reply]
Re^4: Module name case typo silent failure by Anonymous Monk on Sep 19, 2019 at 22:10 UTC
Re: Module name case typo silent failure by Anonymous Monk on Sep 20, 2019 at 09:13 UTC
use strict (upper or lower case) joke Acme::require::case https://rt.perl.org/Public/Bug/Display.html?id=22077 https://rt.perl.org/Public/Bug/Display.html?id=126167 https://perl5.git.perl.org/perl.git/commit/67ba812d5fe08169b8a39cdc1f4945c5e08f32e1?f=lib/strict.pm https://www.nntp.perl.org/group/perl.perl5.porters/2007/04/msg123299.html	[reply]
Re^2: Module name case typo silent failure by LanX (Saint) on Sep 20, 2019 at 11:47 UTC
Thanks! Particularly this link ... > Bug #22077 for perl5: Module Loading on Case-Insensitive File Systems ... the confusion between `Apache::Test` and `Apache::test` is indeed annoying. :( Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}	[reply] [d/l] [select]