Only show MultiField alert if fields have errors

[mulhollandms]

I noticed that when using the 'bootstrap3' template pack, the MultiField layout object shows the alert box for errors regardless of whether there actually are any. Based on the 'layouts/multifield.html' template, it seems the only prerequisite for showing the alert is that "form_show_errors" is enabled.

This was just a quick patch to solve my problem without disabling form errors entirely so I'm sure it'll be worth another look-over before marking for review.

[codecov-io]

Codecov Report

Merging #980 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #980      +/-   ##
==========================================
+ Coverage   96.51%   96.52%   +<.01%     
==========================================
  Files          24       24              
  Lines        2729     2732       +3     
  Branches      241      241              
==========================================
+ Hits         2634     2637       +3     
  Misses         54       54              
  Partials       41       41

Impacted Files	Coverage Δ
crispy_forms/layout.py	96.29% <100%> (+0.05%)	⬆️

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[smithdc1]

hi @mulhollandms

Could I suggest a couple of other options to try fix this which don't need has_errors.

1. Change this line to {% if form_show_errors and field.errors %}
   

   django-crispy-forms/crispy_forms/templates/bootstrap3/layout/multifield.html

   Line 5 in 77f4ea7

   {% if form_show_errors %}

2. move <div class="alert alert-danger" role="alert"> within the for loop, probably after this line?
   

   django-crispy-forms/crispy_forms/templates/bootstrap3/layout/multifield.html

   Line 8 in 77f4ea7

   {% if field.errors %}

These seem to help, but I'm less familiar with bootstrap3

[mulhollandms]

@smithdc1 ,

Moving the alert div inside the for loop would mean that if multiple errors are present, each field with errors will have its own separate alert with a list of errors, which looks strange and doesn't seem to line up well with the documented use:

this renders all the fields wrapped in a div and when there are errors in the form submission, they are shown in a list instead of each one surrounding the field

updated example:

Also, yeah I was a little hesitant about just adding has_errors to MultiField but the only other attr that indicates whether this subset of fields has errors is the css_class. On that note, I also found that with multiple errors, the MultiField div ends up with class="ctrlHolder error error", which is due to this loop.

django-crispy-forms/crispy_forms/layout.py

Lines 315 to 318 in 77f4ea7

	if context['form_show_errors']:
	for field in map(lambda pointer: pointer[1], self.get_field_names()):
	if field in form.errors:
	self.css_class += " error"

Might be worth adding a break to get out of that loop once the error class is added