Move declaration of DETECTOR_VERSION upstream

** Why are these changes being introduced:

We initially tried populating the detector_version value in the
Detection and Categorization records within those models themselves via
a before_create lifecycle hook. That proved unworkable because the app
ends up calling .find_by_or_create, and the "find" part of that pathway
has no relevant lifecycle hook to pick up the current value. This caused
a bug that would have prevented the anticipated creation of new records
when we bump the DETECTOR_VERSION env variable.

** Relevant ticket(s):

* https://mitlibraries.atlassian.net/browse/tco-90

** How does this address that need:

This abandons the attempt to populate detector_version via a lifecycle
hook, and moves that responsibility to the models which initiate the
creation of these records (where they are already defining the other
needed fields).

Because these values are now being defined upstream, the lifecycle hook
is no longer needed, so we remove it.

Removing this lifecycle hook causes some other tests to fail. Some of
those tests need to be updated to _also_ define detector_version, while
a test about that auto-population feature is just deleted as no longer
relevant.

** Document any side effects to this change:

No side effects other than our code is a little less sparse than I was
hoping for. Such is life.

app/models/categorization.rb

@@ -24,18 +24,6 @@ class Categorization < ApplicationRecord
   belongs_to :term
   belongs_to :category
 
-  # We use the before_create hook to prevent needing to override the initialize method, which Rails frowns upon.
-  before_create :set_defaults
-
   # These scopes allow for easy filtering of Categorization records by a single parameter.
   scope :current, -> { where(detector_version: ENV.fetch('DETECTOR_VERSION', 'unset')) }
-
-  private
-
-  # This looks up the current Detector Version from the environment, storing the value as part of the record which is
-  # about to be saved. This prevents the rest of the application from having to worry about this value, while also
-  # providing a mechanism to prevent duplicate records from being created.
-  def set_defaults
-    self.detector_version = ENV.fetch('DETECTOR_VERSION', 'unset')
-  end
 end

app/models/detection.rb

@@ -23,9 +23,6 @@ class Detection < ApplicationRecord
   belongs_to :term
   belongs_to :detector
 
-  # We use the before_create hook to prevent needing to override the initialize method, which Rails frowns upon.
-  before_create :set_defaults
-
   # These scopes allow for easy filtering of Detection records by a single parameter.
   scope :current, -> { where(detector_version: ENV.fetch('DETECTOR_VERSION', 'unset')) }
   scope :for_detector, ->(detector) { where(detector_id: detector.id) }
@@ -44,13 +41,4 @@ class Detection < ApplicationRecord
   def scores
     detector.detector_categories.map { |dc| { dc.category_id => dc.confidence } }
   end
-
-  private
-
-  # This looks up the current Detector Version from the environment, storing the value as part of the record which is
-  # about to be saved. This prevents the rest of the application from having to worry about this value, while also
-  # providing a mechanism to prevent duplicate records from being created.
-  def set_defaults
-    self.detector_version = ENV.fetch('DETECTOR_VERSION', 'unset')
-  end
 end

app/models/detector/journal.rb

@@ -59,7 +59,8 @@ def self.record(term)
 
       Detection.find_or_create_by(
         term:,
-        detector: Detector.where(name: 'Journal').first
+        detector: Detector.where(name: 'Journal').first,
+        detector_version: ENV.fetch('DETECTOR_VERSION', 'unset')
       )
 
       nil

app/models/detector/standard_identifiers.rb

@@ -30,7 +30,8 @@ def self.record(term)
       si.identifiers.each_key do |k|
         Detection.find_or_create_by(
           term:,
-          detector: Detector.where(name: k.to_s.upcase).first
+          detector: Detector.where(name: k.to_s.upcase).first,
+          detector_version: ENV.fetch('DETECTOR_VERSION', 'unset')
         )
       end
 

app/models/detector/suggested_resource.rb

@@ -117,7 +117,8 @@ def self.record(term)
 
       Detection.find_or_create_by(
         term:,
-        detector: Detector.where(name: 'SuggestedResource').first
+        detector: Detector.where(name: 'SuggestedResource').first,
+        detector_version: ENV.fetch('DETECTOR_VERSION', 'unset')
       )
 
       nil

app/models/term.rb

@@ -52,7 +52,8 @@ def calculate_categorizations
         Categorization.find_or_create_by(
           term: self,
           category: Category.where(id: cat).first,
-          confidence: calculate_confidence(vals)
+          confidence: calculate_confidence(vals),
+          detector_version: ENV.fetch('DETECTOR_VERSION', 'unset')
         )
       end
     end

test/models/categorization_test.rb

@@ -21,7 +21,8 @@ class CategorizationTest < ActiveSupport::TestCase
     sample = {
       term: terms('hi'),
       category: categories('transactional'),
-      confidence: 0.5
+      confidence: 0.5,
+      detector_version: '1'
     }
 
     Categorization.create!(sample)
@@ -47,7 +48,8 @@ class CategorizationTest < ActiveSupport::TestCase
     new_sample = {
       term: sample.term,
       category: sample.category,
-      confidence: sample.confidence
+      confidence: sample.confidence,
+      detector_version: sample.detector_version
     }
 
     # A purely duplicate record fails to save...
@@ -56,29 +58,10 @@ class CategorizationTest < ActiveSupport::TestCase
     end
 
     # ...but when we update the DETECTOR_VERSION env, now the same record does save.
-    new_version = 'updated'
-
-    assert_not_equal(ENV.fetch('DETECTOR_VERSION'), new_version)
-
-    ClimateControl.modify DETECTOR_VERSION: new_version do
-      Categorization.create!(new_sample)
-
-      assert_equal(initial_count + 1, Categorization.count)
-    end
-  end
-
-  test 'categorizations are assigned the current DETECTOR_VERSION value from env' do
-    new_categorization = {
-      term: terms('hi'),
-      category: categories('transactional'),
-      confidence: 0.96
-    }
-
-    Categorization.create!(new_categorization)
-
-    confirmation = Categorization.last
+    new_sample[:detector_version] = '2'
+    Categorization.create!(new_sample)
 
-    assert_equal(confirmation.detector_version, ENV.fetch('DETECTOR_VERSION'))
+    assert_equal(initial_count + 1, Categorization.count)
   end
 
   test 'categorization current scope filters on current env value' do

test/models/detection_test.rb

@@ -19,7 +19,8 @@ class DetectionTest < ActiveSupport::TestCase
 
     sample = {
       term: terms('hi'),
-      detector: detectors('doi')
+      detector: detectors('doi'),
+      detector_version: '1'
     }
 
     Detection.create!(sample)
@@ -44,7 +45,8 @@ class DetectionTest < ActiveSupport::TestCase
 
     new_sample = {
       term: sample.term,
-      detector: sample.detector
+      detector: sample.detector,
+      detector_version: '1'
     }
 
     # A purely duplicate record fails to save...
@@ -53,28 +55,10 @@ class DetectionTest < ActiveSupport::TestCase
     end
 
     # ...but when we update the DETECTOR_VERSION env, now the same record does save.
-    new_version = 'updated'
-
-    assert_not_equal(ENV.fetch('DETECTOR_VERSION'), new_version)
-
-    ClimateControl.modify DETECTOR_VERSION: new_version do
-      Detection.create!(new_sample)
-
-      assert_equal(initial_count + 1, Detection.count)
-    end
-  end
-
-  test 'detections are assigned the current DETECTOR_VERSION value from env' do
-    new_detection = {
-      term: terms('hi'),
-      detector: detectors('pmid')
-    }
-
-    Detection.create!(new_detection)
-
-    confirmation = Detection.last
+    new_sample[:detector_version] = '2'
+    Detection.create!(new_sample)
 
-    assert_equal(confirmation.detector_version, ENV.fetch('DETECTOR_VERSION'))
+    assert_equal(initial_count + 1, Detection.count)
   end
 
   test 'detector current scope filters on current env value' do