Class: OnlineMigrations::DataMigrations::BackfillDoNotMergeOnElectricalSpecs

Inherits:
OnlineMigrations::DataMigration
  • Object
show all
Defined in:
lib/online_migrations/data_migrations/backfill_do_not_merge_on_electrical_specs.rb

Overview

Sets legacy_do_not_merge = true on every existing product_specifications
row whose token is in Models::ItemSpecificationHelper::PER_ITEM_SPEC_TOKENS
(watts, voltage, amps, ohms).

HISTORICAL — completed in production on 2026-05-07. Kept only so the
migration chain stays replayable; it describes a world that no longer
exists.

Background as it stood then:
Maintenance::ItemMaintenance#consolidate_specs ran nightly and
collapsed any rows whose (token, grouping, sku_regexp, method, text_blurb, units, image_id, formatter) tuple matched into a single
row — unless the merge opt-out was set. For tokens whose values
coincidentally match across unrelated SKUs (a 175W cable kit and a
175W towel warmer are not "the same spec"), that collapse silently
welded independent items into a shared row. Editing one then mutated
the others. create_or_set_spec_value set the flag for these tokens at
write time, and this migration backfilled it onto pre-existing rows.

Since #1856 the consolidator is gone, no application code writes
legacy_do_not_merge, and nothing reads it — this class and its two
siblings are the only remaining references.

See Also:

Constant Summary collapse

BATCH_SIZE = 
1_000
TOKENS = 
Models::ItemSpecificationHelper::PER_ITEM_SPEC_TOKENS.map(&:to_s).freeze

Delegated Instance Attributes collapse

Instance Method Summary collapse

Instance Method Details

#collection ⇒ ActiveRecord::Batches::BatchEnumerator

Yields batches of ProductSpecification rows that still need the
flag flipped.

Returns:

  • (ActiveRecord::Batches::BatchEnumerator)

Raises:

  • (ActiveRecord::ActiveRecordError) —

    on database error.



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# File 'lib/online_migrations/data_migrations/backfill_do_not_merge_on_electrical_specs.rb', line 39

def collection
  candidate_relation.in_batches(of: BATCH_SIZE)
end

#count ⇒ Integer

Number of rows that still need the flag flipped. Used by
online_migrations for progress reporting.

Returns:

  • (Integer)

Raises:

  • (ActiveRecord::ActiveRecordError) —

    on database error.



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# File 'lib/online_migrations/data_migrations/backfill_do_not_merge_on_electrical_specs.rb', line 60

delegate :count, to: :candidate_relation

#process(specs) ⇒ void

This method returns an undefined value.

Flips legacy_do_not_merge to true on every row in the batch via a single
update_all (no callbacks — this is a flag-only change).

Parameters:

Raises:

  • (ActiveRecord::ActiveRecordError) —

    propagated from update_all.



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# File 'lib/online_migrations/data_migrations/backfill_do_not_merge_on_electrical_specs.rb', line 50

def process(specs)
  specs.update_all(legacy_do_not_merge: true)
end