Add perlcritic to Travis with gentle severity

[jknphy]

In order to add perlcritic to Travis (run succesfully make perlcritic in our ci) and start to introduce some new policies we need:

• First, apply default policy (empty means --severity gentle or --severity 5 according documentation) and modify tests accordingly. This are potential modification in files needed to successful pass a default call to make perlcritic.
  I had to exclude for the moment policy ProhibitStringyEval as I could not resolve v1 and v2 simply replacing them with { } due to in turn makes `make test' failing on importing modules.
• Second, include HashKeyQuote perlcritic policy(one of the not used existing policies in the original makefile) and modify files accordingly.
• Third, do the same for the other existing policy ConsistentQuoteLikeWords.
• Finally, add new policy Perl::Critic::Policy::ControlStructures::ProhibitDeepNests and use a configuration .perlcriticrc and setup max_nests where does not fail (fixing one level)
• Besides as an enhancement git grep is not producing any visual data except for the unnecessary user intervention so I added the option to be silent. Also I realized that we should not check os-autoinst as it is a different repo.

Previous steps are reflected in different commits in case something potentially could go south.

Related ticket

https://progress.opensuse.org/issues/44165

[okurz]

I wonder with what change we lost perlcritic checks to be executed against each PR in the past …

[jknphy]

There is a call to perlcritic in target test-merge in Makefile and it fulfills its purpose in user's local env but I don't see we run this in Travis. My best guess is that the list of changed files given by
git diff --name-only FETCH_HEAD `git merge-base FETCH_HEAD master` is not returning anything and it does in local env.
According with Travis docs "we build the merge between the source branch and the upstream branch". That could be a possible reason why it is not tracking the differences between both branches. I've no idea if this worked in the past as it is hard to track travis logs from a lot of time ago.

[rwx788]

LGTM. Do you have any example of the output if such check fails? As we don't want to confuse people.

[okurz]

@coolo do you have an idea regarding #6294 (review) and #6294 (comment) ?

[coolo]

this is 2 years old - it's not too unlikely travis changed something in between :)

[jknphy]

@rwx788 for example if we would activate policy [BuiltinFunctions::ProhibitStringyEval] in .perlcriticrc removing the leading - user would get this output:

make perlcritic                                  
PERL5LIB=tools/lib/perlcritic:$PERL5LIB perlcritic --quiet --gentle --exclude=os-autoinst ./tests ./products ./lib
lib/main_common.pm: Expression form of "eval" at line 262, column 5.  See page 161 of PBP.  (Severity: 5)
lib/main_common.pm: Expression form of "eval" at line 265, column 9.  See page 161 of PBP.  (Severity: 5)
make: *** [Makefile:93: perlcritic] Error 2

With a quick google search of the kind perlcritic Expression form of "eval" should lead him/her to specific policy doc in CPAN

[okurz]

@kraih WDYT?

[kraih]

@okurz My plan for openQA and os-autoinst is to use Perl::Critic::Freenode with severity 4 (--stern). If that makes sense for this repo i'm not sure yet, a first scan looks like this.

[okurz]

@kraih I see. I plan to extend the perl critic checks later and mentioned your comment in https://progress.opensuse.org/issues/44075#note-2