Handle metrical and boolean attribute types as variant axis (#106)

[lruozzi9]

Fixes #106

Changes proposed in this pull request:

• Handle metrical and boolean attribute types as variant axle

@webgriffe/wg-devs what do you think about this PR ?

[lruozzi9]

@mmenozzi @LucaGallinari gentle reminder 😀.

[azambon]

Qui c'è un potenziale problemino: si permette il carattere _ all'interno dei singoli frammenti, e lo si usa anche come separatore.
In pratica, se qualcuno passa due $pieces che valgono, ad esempio 'a_b' e 'c', questi verrebbero compattati nel codice 'a_b_c'. Però si otterrebbe lo stesso codice anche con i $pieces 'a' e 'b_c'.

Per evitare questo bisognerebbe usare un separatore che non può comparire anche all'interno dei singoli pieces

[fabianaromagnoli]

I'm afraid we can't because option codes can only be letters, numbers, dashes and underscores. Anyway I think this is a very unlikely case that we can safely ignore.

[fabianaromagnoli]

Or... maybe we should simplify it: considering that this issue was raised by the introduction of metric attributes, and that the only characters that we need to exclude are characters that appear in numeric values, that's to say dots and maybe commas, wouldn't it be better to make a simple str_replace to remove only dots and commas? What do you think @LucaGallinari and @azambon ?

[mmenozzi]

We should also be sure to not introduce a BC break by changing the logic the production option value code is generated.

[lruozzi9]

We should also be sure to not introduce a BC break by changing the logic the production option value code is generated.

Actually only the select attribute type is supported by the ProductOptionValueHandler and in Akeneooption code may contain only letters, numbers and underscores. So this change should not cause any BC in the previous code generation.

[LucaGallinari]

The only BC could be on the "slugification" of the option value code for select attribute, cause boolean and metric values were not supported.

For select attributes, before we did:

$fullValueCode = $optionCode . '_' . $partialValueCode;

where $partialValueCode is the code of the value. Given that $optionCode and $partialValueCode are two codes, they could not (and actually cannot) contains dots and points.
Now we do:

$slugifiedPieces = array_map(static function (string $word): string {
    return str_replace(['.', ','], '', $word);
}, $pieces);

return implode('_', $slugifiedPieces);

where $pieces "contains" $optionCode and $partialValueCode, and the new str_replace is idempotent for select attributes cause, as said before, the two codes cannot contain dots and points. Thus, the result is the same before and now (this is "softly" asserted in some phpspec tests that checks the generated code for select attribute, here and here)