Change Unit.multiplier type from decimal to float

Remove remnants related to BigDecimal.

app/controllers/units_controller.rb

@@ -17,7 +17,7 @@ class UnitsController < ApplicationController
   end
 
   def create
-    @unit = current_user.units.new(unit_params)
+    @unit = current_user.units.new(params.expect(Unit::ATTRIBUTES))
     if @unit.save
       @before = @unit.successive
       flash.now[:notice] = t('.success', unit: @unit)
@@ -30,7 +30,7 @@ class UnitsController < ApplicationController
   end
 
   def update
-    if @unit.update(unit_params.except(:base_id))
+    if @unit.update(params.except(:base_id).expect(Unit::ATTRIBUTES))
       flash.now[:notice] = t('.success', unit: @unit)
     else
       render :edit
@@ -40,11 +40,11 @@ class UnitsController < ApplicationController
   # TODO: Avoid double table width change by first un-hiding table header,
   # then displaying index, e.g. by re-displaying header in index
   def rebase
-    permitted = params.require(:unit).permit(:base_id)
-    permitted.merge!(multiplier: 1) if permitted[:base_id].blank? && @unit.multiplier != 1
+    unit_params = params.expect(unit: :base_id)
+    unit_params.merge!(multiplier: 1.0) if unit_params[:base_id].blank?
 
     @previous_base = @unit.base
-    @unit.update!(permitted)
+    @unit.update!(unit_params)
 
     @before = @unit.successive
     if @unit.multiplier_previously_changed?
@@ -59,10 +59,6 @@ class UnitsController < ApplicationController
 
   private
 
-  def unit_params
-    params.require(:unit).permit(Unit::ATTRIBUTES)
-  end
-
   def find_unit
     @unit = current_user.units.find_by!(id: params[:id])
   end

app/helpers/application_helper.rb

@@ -103,15 +103,19 @@ module ApplicationHelper
     def number_field(method, options = {})
       attr_type = object.type_for_attribute(method)
       case attr_type.type
-      when :decimal
+      when :float, :double
         options[:value] = object.public_send(method)&.to_scientific
-        options[:step] ||= BigDecimal(10).power(-attr_type.scale)
-        options[:max] ||= BigDecimal(10).power(attr_type.precision - attr_type.scale) -
-          options[:step]
-        options[:min] = options[:min] == :step ? options[:step] : options[:min]
-        options[:min] ||= -options[:max]
-        options[:size] ||= attr_type.precision / 2
-      when :float
+        options[:step] ||= :any
+        options[:min] ||= Float::MIN_15
+        options[:max] ||= Float::MAX_15
+        # Longest possible number (written not using exponent):
+        #   sign (1), leading 0 (1), dot (1), exponent 0s (307), digits (15).
+        # This is only upper bound, which cannot guarantee the number won't fall
+        # out of range.
+        # TODO: add `[pattern]` to limit precision and (possibly) replace `[maxlength]`?
+        # NOTE: `[pattern]` is unavailable on `input[type=number]` and `[min]/[max]` is
+        # unavailable on `input[type=text]`.
+        options[:maxlength] ||= 3 + Float::MIN_10_EXP + Float::DIG
         options[:size] ||= 6
       end
       super

app/models/unit.rb

@@ -1,5 +1,5 @@
 class Unit < ApplicationRecord
-  ATTRIBUTES = [:symbol, :description, :multiplier, :base_id]
+  ATTRIBUTES = {unit: [:symbol, :description, :multiplier, :base_id]}
 
   belongs_to :user, optional: true
   belongs_to :base, optional: true, class_name: "Unit"
@@ -14,8 +14,8 @@ class Unit < ApplicationRecord
   validates :symbol, presence: true, uniqueness: {scope: :user_id},
     length: {maximum: type_for_attribute(:symbol).limit}
   validates :description, length: {maximum: type_for_attribute(:description).limit}
-  validates :multiplier, numericality: {equal_to: 1}, unless: :base
-  validates :multiplier, numericality: {greater_than: 0, precision: true, scale: true}, if: :base
+  validates :multiplier, numericality: {equal_to: 1.0}, unless: :base
+  validates :multiplier, numericality: {greater_than: 0.0}, if: :base
 
   scope :defaults, ->{ where(user: nil) }
   scope :defaults_diff, ->{
@@ -102,10 +102,10 @@ class Unit < ApplicationRecord
     user_id.nil?
   end
 
-  # Should only by invoked on Units returned from #defaults_diff which are #portable
+  # Should only by invoked on Units returned from #defaults_diff which are #portable.
   def port!(recipient)
     recipient_base = base && Unit.find_by!(symbol: base.symbol, user: recipient)
-    params = slice(ATTRIBUTES - [:symbol, :base_id])
+    params = slice(ATTRIBUTES[:unit] - [:symbol, :base_id])
     Unit.find_or_initialize_by(user: recipient, symbol: symbol)
       .update!(base: recipient_base, **params)
   end

app/views/units/_form.html.erb

@@ -9,7 +9,7 @@
       <%= form.text_area :description, cols: 30, rows: 1, escape: false %>
     </td>
     <td>
-      <%= form.number_field :multiplier, required: true, size: 10, min: :step if @unit.base_id? %>
+      <%= form.number_field :multiplier, required: true if @unit.base_id? %>
     </td>
 
     <td class="flex">

app/views/units/_unit.html.erb

@@ -11,7 +11,7 @@
       data: {turbo_stream: true} %>
   </td>
   <td><%= unit.description %></td>
-  <td class="ralign"><%= unit.multiplier.to_html %></td>
+  <td class="ralign"><%= unit.multiplier.to_html if unit.base_id? %></td>
 
   <% if current_user.at_least(:active) %>
     <td class="flex">

app/views/units/rebase.turbo_stream.erb

@@ -1,4 +1,4 @@
 <%= turbo_stream.remove @unit %>
 <%= turbo_stream.replace @previous_base if @previous_base %>
-<%= turbo_stream.replace @unit.base if @unit.base_id? && (@previous_base.id != @unit.base_id) %>
+<%= turbo_stream.replace @unit.base if @unit.base_id? && (@previous_base&.id != @unit.base_id) %>
 <%= @before ? turbo_stream.before(@before, @unit) : turbo_stream.append(:units, @unit) %>