Commit d374d0be authored by Andreas Brandl's avatar Andreas Brandl

Backwards-compat for migration specs.

The specs are based on a schema version that doesn't know about
`internal_ids` table. However, the actual code being execute relies on
it.
parent d4bb363f
......@@ -17,6 +17,8 @@ class InternalId < ActiveRecord::Base
validates :usage, presence: true
REQUIRED_SCHEMA_VERSION = 20180305095250
# Increments #last_value and saves the record
#
# The operation locks the record and gathers a `ROW SHARE` lock (in PostgreSQL).
......@@ -30,8 +32,22 @@ class InternalId < ActiveRecord::Base
class << self
def generate_next(subject, scope, usage, init)
# Shortcut if `internal_ids` table is not available (yet)
# This can be the case in other (unrelated) migration specs
return (init.call(subject) || 0) + 1 unless available?
InternalIdGenerator.new(subject, scope, usage, init).generate
end
def available?
@available_flag ||= ActiveRecord::Migrator.current_version >= REQUIRED_SCHEMA_VERSION # rubocop:disable Gitlab/PredicateMemoization
end
# Flushes cached information about schema
def reset_column_information
@available_flag = nil
super
end
end
class InternalIdGenerator
......@@ -49,12 +65,12 @@ class InternalId < ActiveRecord::Base
# subject: The instance we're generating an internal id for. Gets passed to init if called.
# scope: Attributes that define the scope for id generation.
# usage: Symbol to define the usage of the internal id, see InternalId.usages
# init: Block that gets called to initialize InternalId record if not yet present (optional)
# init: Block that gets called to initialize InternalId record if not present
attr_reader :subject, :scope, :init, :scope_attrs, :usage
def initialize(subject, scope, usage, init)
@subject = subject
@scope = scope
@init = init || ->(s) { 0 }
@init = init
@usage = usage
raise 'scope is not well-defined, need at least one column for scope (given: 0)' if scope.empty?
......
......@@ -12,9 +12,9 @@ describe InternalId do
end
describe '.generate_next' do
context 'in the absence of a record' do
subject { described_class.generate_next(issue, scope, usage, init) }
context 'in the absence of a record' do
it 'creates a record if not yet present' do
expect { subject }.to change { described_class.count }.from(0).to(1)
end
......@@ -47,6 +47,21 @@ describe InternalId do
normalized = seq.map { |i| i - seq.min }
expect(normalized).to eq((0..seq.size - 1).to_a)
end
context 'with an insufficient schema version' do
before do
described_class.reset_column_information
expect(ActiveRecord::Migrator).to receive(:current_version).and_return(InternalId::REQUIRED_SCHEMA_VERSION - 1)
end
let(:init) { double('block') }
it 'calculates next internal ids on the fly' do
val = rand(1..100)
expect(init).to receive(:call).with(issue).and_return(val)
expect(subject).to eq(val + 1)
end
end
end
describe '#increment_and_save!' do
......
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