fix: accept nil values when validating URLs

[iloveitaly]

without this, it's impossible to allow nil values.

nil constraints should be set elsewhere and be allowed in this library from my pov.

[codecov]

Codecov Report

Merging #150 (68995a5) into main (8c57df9) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main      #150   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           23        23           
  Lines          189       190    +1     
=========================================
+ Hits           189       190    +1     

Files Changed	Coverage Δ
lib/url.ex	100.00% <100.00%> (ø)

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[nelsonic]

Hi @iloveitaly 👋
Could you please clarify the use case for a nil value being OK? 💭

[iloveitaly]

Not all fields on my model are required. In this case, a nil value could be passed and converted into a NULL on the DB side. Essentially, I want to leave a field blank.

[nelsonic]

Hmm ... this feels like something that can be checked in the changeset/2 function
or defined declaratively in the schema ...
I'm not against merging/publishing this change necessarily,
I'm just curious if this can be achieved without allowing nil (NULL) values for URLs because nil isn't a valid URL ... 💭

[iloveitaly]

@nelsonic do you know what I need to add to:

schema "things" do
  field :url, Fields.Url
end

so a null/nil value is accepteed?

[iloveitaly]

@nelsonic friendly ping here!