Setting paper-input.value messes with minlength validation

[stivaliserna]

Description

Using polymer 2, if I have a paper-input with some validation:

              <paper-input value="{{x}}"
                            auto-validate
                            id="pass"
                            minlength="12"
                            required
                            type="password">
              </paper-input>

Works ok if users go and type into the input. Whoever, if I programatically change the input value, the validation is lost:

const input = element.shadowRoot.querySelector('#pass')

input.value = 'too-short'
input.validate() // => true

Expected outcome

input.validate() should be false, because value is shorter than minlength.

Actual outcome

input.validate() is true.

Steps to reproduce

1. Define a paper-input with some minlength attribute
2. Programatically set input's value to something shorter
3. Call .validate()

Browsers Affected

• [X] Chrome
• [X] Firefox
• [ ] Safari 9
• [ ] Safari 8
• [ ] Safari 7
• [ ] Edge
• [ ] IE 11
• [ ] IE 10