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# frozen_string_literal: true
require 'spec_helper'
RSpec.describe IssueRebalancingService do
let_it_be(:project, reload: true) { create(:project) }
let_it_be(:user) { project.creator }
let_it_be(:start) { RelativePositioning::START_POSITION }
let_it_be(:max_pos) { RelativePositioning::MAX_POSITION }
let_it_be(:min_pos) { RelativePositioning::MIN_POSITION }
let_it_be(:clump_size) { 300 }
let_it_be(:unclumped, reload: true) do
(1..clump_size).to_a.map do |i|
create(:issue, project: project, author: user, relative_position: start + (1024 * i))
end
end
let_it_be(:end_clump, reload: true) do
(1..clump_size).to_a.map do |i|
create(:issue, project: project, author: user, relative_position: max_pos - i)
end
end
let_it_be(:start_clump, reload: true) do
(1..clump_size).to_a.map do |i|
create(:issue, project: project, author: user, relative_position: min_pos + i)
end
end
before do
stub_feature_flags(issue_rebalancing_with_retry: false)
end
def issues_in_position_order
project.reload.issues.reorder(relative_position: :asc).to_a
end
shared_examples 'IssueRebalancingService shared examples' do
it 'rebalances a set of issues with clumps at the end and start' do
all_issues = start_clump + unclumped + end_clump.reverse
service = described_class.new(project.issues.first)
expect { service.execute }.not_to change { issues_in_position_order.map(&:id) }
all_issues.each(&:reset)
gaps = all_issues.take(all_issues.count - 1).zip(all_issues.drop(1)).map do |a, b|
b.relative_position - a.relative_position
end
expect(gaps).to all(be > RelativePositioning::MIN_GAP)
expect(all_issues.first.relative_position).to be > (RelativePositioning::MIN_POSITION * 0.9999)
expect(all_issues.last.relative_position).to be < (RelativePositioning::MAX_POSITION * 0.9999)
end
it 'is idempotent' do
service = described_class.new(project.issues.first)
expect do
service.execute
service.execute
end.not_to change { issues_in_position_order.map(&:id) }
end
it 'does nothing if the feature flag is disabled' do
stub_feature_flags(rebalance_issues: false)
issue = project.issues.first
issue.project
issue.project.group
old_pos = issue.relative_position
service = described_class.new(issue)
expect { service.execute }.not_to exceed_query_limit(0)
expect(old_pos).to eq(issue.reload.relative_position)
end
it 'acts if the flag is enabled for the project' do
issue = create(:issue, project: project, author: user, relative_position: max_pos)
stub_feature_flags(rebalance_issues: issue.project)
service = described_class.new(issue)
expect { service.execute }.to change { issue.reload.relative_position }
end
it 'acts if the flag is enabled for the group' do
issue = create(:issue, project: project, author: user, relative_position: max_pos)
project.update!(group: create(:group))
stub_feature_flags(rebalance_issues: issue.project.group)
service = described_class.new(issue)
expect { service.execute }.to change { issue.reload.relative_position }
end
it 'aborts if there are too many issues' do
issue = project.issues.first
base = double(count: 10_001)
allow(Issue).to receive(:relative_positioning_query_base).with(issue).and_return(base)
expect { described_class.new(issue).execute }.to raise_error(described_class::TooManyIssues)
end
end
shared_examples 'rebalancing is retried on statement timeout exceptions' do
subject { described_class.new(project.issues.first) }
it 'retries update statement' do
call_count = 0
allow(subject).to receive(:run_update_query) do
call_count += 1
if call_count < 13
raise(ActiveRecord::QueryCanceled)
else
call_count = 0 if call_count == 13 + 16 # 16 = 17 sub-batches - 1 call that succeeded as part of 5th batch
true
end
end
# call math:
# batches start at 100 and are split in half after every 3 retries if ActiveRecord::StatementTimeout exception is raised.
# We raise ActiveRecord::StatementTimeout exception for 13 calls:
# 1. 100 => 3 calls
# 2. 100/2=50 => 3 calls + 3 above = 6 calls, raise ActiveRecord::StatementTimeout
# 3. 50/2=25 => 3 calls + 6 above = 9 calls, raise ActiveRecord::StatementTimeout
# 4. 25/2=12 => 3 calls + 9 above = 12 calls, raise ActiveRecord::StatementTimeout
# 5. 12/2=6 => 1 call + 12 above = 13 calls, run successfully
#
# so out of 100 elements we created batches of 6 items => 100/6 = 17 sub-batches of 6 or less elements
#
# project.issues.count: 900 issues, so 9 batches of 100 => 9 * (13+16) = 261
expect(subject).to receive(:update_positions).exactly(261).times.and_call_original
subject.execute
end
end
context 'when issue_rebalancing_optimization feature flag is on' do
before do
stub_feature_flags(issue_rebalancing_optimization: true)
end
it_behaves_like 'IssueRebalancingService shared examples'
context 'when issue_rebalancing_with_retry feature flag is on' do
before do
stub_feature_flags(issue_rebalancing_with_retry: true)
end
it_behaves_like 'IssueRebalancingService shared examples'
it_behaves_like 'rebalancing is retried on statement timeout exceptions'
end
end
context 'when issue_rebalancing_optimization feature flag is off' do
before do
stub_feature_flags(issue_rebalancing_optimization: false)
end
it_behaves_like 'IssueRebalancingService shared examples'
context 'when issue_rebalancing_with_retry feature flag is on' do
before do
stub_feature_flags(issue_rebalancing_with_retry: true)
end
it_behaves_like 'IssueRebalancingService shared examples'
it_behaves_like 'rebalancing is retried on statement timeout exceptions'
end
end
end
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