NumberField: setting min enables validation for step

[pekam]

Steps to reproduce:

1. Create a simple <vaadin-number-field> without any attributes/properties
2. Set the value to 1.5 (notice that the field is valid)
3. Set min=0 for the field

Expected outcome: the field is still valid

Actual outcome: the field becomes invalid

When the step is not explicitly set by user, it's used just for the plus and minus buttons, but not for validation. Setting the step property enables the step-based validation, but it's unexpected that setting a min-constraint does the same.

These lines reveal the issue:

vaadin-text-field/src/vaadin-number-field.html

Lines 345 to 347 in 7599194

	if (this.min !== undefined || this.max !== undefined || this.step !== 1) {
	this.invalid = !this.inputElement.checkValidity();
	}

I suggest that instead of asking the native input element to validate the field, add the trivial implementation of min/max-validation here. Only if the step has changed, validate via the native input.

Another problem is that setting step=1 doesn't trigger the step-based validation, but step="1" does. This logic should be based on whether user has set the property, not based on its absolute value.

[pekam]

I suggest that instead of asking the native input element to validate the field, add the trivial implementation of min/max-validation here. Only if the step has changed, validate via the native input.

Another way to fix this: set this.inputElement.step = 'any' when setting the initial this.step = 1. When user overrides the step, propagate it to inputElement as usual.
See: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/input/number#step