When contribution to the code of someone else we are supposed to stick to the same layout that was used by the original author, but when you take over a module and start to maintain yourself you might feel more freedom to change the layout.

In this case the source code already had a mix of style, or at least a mix in the indentation. Some lines used tabs some used spaces. This make the code very hard to read an maintain.

It is far better to stick to a well defined layout that can be easily generated.

Hence we use Perl::Tidy to beautify the code

The Code-TidyAll distribution provides a command line script called tidyall that will use Perl::Tidy to change the layout of the code.

This tandem needs 2 configuration file.

The .perltidyrc file contains the instructions to Perl::Tidy that describes the layout of a Perl-file. We used the following file copied from the source code of the Perl Maven project.


# Break a line after opening/before closing token.

The tidyall command uses a separate file called .tidyallrc that describes which files need to be beautified.

select = {lib,t}/**/*.{pl,pm,t}
select = Makefile.PL
select = {mod2html,podtree2html,pods2html,perl2html}
argv = --profile=$ROOT/.perltidyrc

select = .gitignore

Once I installed Code::TidyAll and placed those files in the root directory of the project, I could run tidyall -a.

That created a directory called .tidyall.d/ where it stores cached versions of the files, and changed all the files that were matches by the select statements in the .tidyallrc file.

Then, I added .tidyall.d/ to the .gitignore file to avoid adding that subdirectory to the repository and ran tidyall -a again to make sure the .gitignore file is sorted.

Before commiting the files, I ran the test cycle again:

$ perl Makefile.PL
$ make
$ make test


Beauty contest or testing tidyness

It is not enough to run perltidy once. We have to make sure we keep the source code in the same level of tidyness. We can ensure that by adding a test file that will check if the code is tidy.

In order to run this test we have to make sure the machine has Code::TidyAll installed, but there is no good reason to run this on multiple machines. So it is probably better to write the test script in a way that will only run if Code::TidyAll is installed.

The t/95-tidyall.t with the following content is just like that:

use strict;
use warnings;

use Test::More;

## no critic
eval 'use Test::Code::TidyAll 0.20';
plan skip_all => "Test::Code::TidyAll 0.20 required to check if the code is clean." if $@;

It tries to load the Test::Code::TidyAll module, and skips the tests if it could not load the test module. We can now run make test and in addition to the regular tests, it will also check if the code is tidy.

What would be really good though is if this test also ran on Travis-CI.

No problem, we only have to tell Travis-CI to install the Test::Code::TidyAll module, before running the tests. We can do that by adding the following lines to .travis.yml

before_install: - cpanm --notest Test::Code::TidyAll

use strict;
use warnings;

use Test::More;

## no critic
eval 'use Test::Code::TidyAll 0.20';
plan skip_all => "Test::Code::TidyAll 0.20 required to check if the code is clean." if $@;

Then I commited the changes and went for a walk.

Travis failure

When I cam back and e-mail was already waiting for me, showing a failure on Travis.

Clicking though one of the reports I saw this failure:

t/95-tidyall.t .. could not load plugin class 'Code::TidyAll::Plugin::PerlTidy':
   Can't locate Perl/Tidy.pm in @INC (you may need to install the Perl::Tidy module)

This surprised me a bit. Apparently Test::Code::TidyAll does not automatically install Perl::Tidy. So I changed .travis.yml to install Perl::Tidy as well:

  - cpanm --notest Perl::Tidy
  - cpanm --notest Test::Code::TidyAll

and commtted it.

That fixed Travis.

Keep tidy

From now on, we will have to remember to run tidyall -a every time before committing a change. That way our code will always stay tidy. If we forget and we made a change that make the code untidy, (and we forget to run the tests) then once we push it out to GitHub, Travis will fail and will tell us about the lack of tidyness. Then we'll be able to run tidyall -a and make a new commit. This will also ensure that people who might want to contribute to our code will use the same layout.