comment on

Welcome to the Monastery.

"I tried setting PERL5LIB and use lib pragma ... but din't help." [sic]

You don't show exactly what you did: here's some pointers.

PERL5LIB needs to be set before you call your scripts and made available to them (e.g. via export).
use lib should be used before use DateTime; be careful of relative paths.
Check that @INC has the path you set: consider doing so in a CHECK or INIT block.
Are you running in "taint mode"? See -T and -t in perlrun. See perlsec and, in particular, the "Taint mode and @INC" section.
Are you using the warnings pragma?

"I would like to know how Perl gurus/monks solve and contribute to CPAN Module."

My basic process would be as follows. I'll reference the current DateTime module; however, this would be what I'd generally use for any module. You may have different methods for achieving each step — I'm certainly not trying to recommend you use different tools — but the order of steps should be much the same. And, of course, the commands I've used are just examples.

Set up a work area.

$ cd /some/base/work/dir
$ mkdir DateTime
$ cd DateTime
[download]

Get the currrent distribution.

$ wget http://search.cpan.org/CPAN/authors/id/D/DR/DROLSKY/DateTime-1.
+41.tar.gz
$ tar zxvf DateTime-1.41.tar.gz > DateTime-1.41.INSTALL 2>&1
$ view DateTime-1.41.INSTALL  # Check there's no errors
$ cd DateTime-1.41
[download]

Read any relevant documentation.

$ view README  # That's "README.md" for this distro
$ view INSTALL
[download]

Modify the module code.
```
$ cd lib
$ vi DateTime.pm
[download]
```
Write new test(s).
```
$ cd ../t
$ vi new_test.t
[download]
```

Create Makefile, build and test.

$ cd ..
$ perl Makefile.PL
$ make
$ make test
[download]

Repeat the last three steps until the code does what you want and the tests all pass.
```
$ make realclean
$ # ... repeat commands already shown ...
[download]
```

— Ken

In reply to Re: How do I write a new sub in a git cloned CPAN module and test it by bypassing the Original Module by kcott
in thread How do I write a new sub in a git cloned CPAN module and test it bypassing the Original Module by yysachinyy

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