[MaxGhenis]

This draft now sits on main at d60944e9e, which holds #1966 and #2002, so CI can test 28 open pull requests as one tree. Please don't merge it: I'll close it and delete the branch when the run finishes, and post the result here first.

I merged these in order, and the ones after "with" arrive inside the pull request they follow:

• Run the tests that need the dataset in their own CI shard #2893 Run the certified aggregate tests in one CI shard
• Place the UC and Pension Credit QYP terminal date from the birth date #2300 Place the UC and Pension Credit QYP terminal date from the birth date
• Name heads that are NaN at baseline in the counted-once check #2854 Name heads that are NaN at baseline in the counted-once check
• Charge no Plan 5 student loan repayment before 6 April 2026 #2864 Charge no Plan 5 student loan repayment before 6 April 2026
• Guard against random draws in the engine #2873 Guard against random draws in the engine
• Price real incomes to a fixed base year #2876 Price real incomes to a fixed base year
• Move the VAT survey coverage to 0.69 on Microcosm a6299504  #2634 Move the VAT survey coverage to 0.69 on Microcosm a6299504
• Bar income-related ESA at pensionable age and on Pension Credit #2807 Bar income-related ESA at pensionable age and on Pension Credit
• Document the State Pension's 52 weeks; test survey data to Income Tax #2818 Document the State Pension's 52 weeks; test survey data to Income Tax
• Start SDLT's 2014 to 2018 changes on their statutory dates #2837 Start SDLT's 2014 to 2018 changes on their statutory dates
• Pay the Scottish Carer Supplement for each Carer Support award week #2857 Pay the Scottish Carer Supplement for each Carer Support award week
• Pay carer benefits only for caring for a severely disabled person #2860 Pay carer benefits only for caring for a severely disabled person
• Count UC carer awards for severe disability and Scottish CTR premiums #2827 Count UC carer awards for severe disability and Scottish CTR premiums, at 835fab99c, its real merge of main
• Set reliefs and allowances against income for the least tax #2830 Set reliefs and allowances against income for the least tax
• Test PC, CB and CTC QYP exclusion of young Income Support recipients #2302 Test PC, CB and CTC QYP exclusion of young Income Support recipients, with Add CB and CTC qualifying young person routes for school leavers #2301
• Apply SI 2014/1230 reg 28 to the UC qualifying young person test #2845 Apply SI 2014/1230 reg 28 to the UC qualifying young person test
• Fix Scottish tax bands and test Marriage Allowance rates directly #2828 Fix Scottish tax bands and test Marriage Allowance rates directly, at ffa8651ff, its real merge of main
• Deduct only the tax Council Tax Reduction schemes allow #2834 Deduct only the tax Council Tax Reduction schemes allow
• Add overseas and other real estate to property wealth and capital #2688 Add overseas and other real estate to property wealth and capital, with Value means-tested capital less 10% sale expenses and secured debt #1969
• Count Carer's Allowance earnings-limit pence exactly #2543 Count Carer's Allowance earnings-limit pence exactly
• Count only supplied inputs that are still stored in their tier #2308 Count only supplied inputs that are still stored in their tier, with Give UK simulations a working subsample #2265
• Count enhanced PIP daily living and AFIP for the enhanced premium #2808 Count enhanced PIP daily living and AFIP for the enhanced premium
• Give benefit-unit members aged 16 or over a bedroom under LHA rules #2010 Give benefit-unit members aged 16 or over a bedroom under LHA rules, with Fix HB and national CTR non-dependant deductions #2007 and Charge non-dependant deductions within the claimant's benefit unit #2017

No single pull request's CI tests these combinations, and the merges here fix them:

• Count enhanced PIP daily living and AFIP for the enhanced premium #2808 and Give Scotland and Wales working-age CTR their own rules #1966 together left Count enhanced PIP daily living and AFIP for the enhanced premium #2808's Scottish list out of every Scottish working-age award, because Give Scotland and Wales working-age CTR their own rules #1966's route reads the legacy enhanced_disability_premium and is_enhanced_disabled_for_benefits, the flag Count enhanced PIP daily living and AFIP for the enhanced premium #2808 retires. The route now reads council_tax_reduction_enhanced_disability_premium and its condition, and four new cases cover it.
• Apply SI 2014/1230 reg 28 to the UC qualifying young person test #2845 ends UC status for a person entitled to Income Support (SI 2014/1230 regs 2(1) and 28), and Test PC, CB and CTC QYP exclusion of young Income Support recipients #2302's tests keep that status. I restated three YAML cases and two property files to Apply SI 2014/1230 reg 28 to the UC qualifying young person test #2845's reading.
• Add CB and CTC qualifying young person routes for school leavers #2301 ends Child Benefit on a young person's own income-related ESA (reg 8(2)(e)), so Case 13 in Apply SI 2014/1230 reg 28 to the UC qualifying young person test #2845's young person file loses £1,406.60 of income. On Give Scotland and Wales working-age CTR their own rules #1966's route the award rises to the full £1,800.
• Fix Scottish tax bands and test Marriage Allowance rates directly #2828 gives the Marriage Allowance as a Step 6 reduction, so I restated council_tax_reduction_tax_deduction.yaml and its property file from Deduct only the tax Council Tax Reduction schemes allow #2834. At pay of 43,661 the deduction rises from 8,542.56 to 8,555.16, and two more pounds of pay raise it by 252.79 in place of 265.39.
• Give Scotland and Wales working-age CTR their own rules #1966 takes Scottish working-age awards off Deduct only the tax Council Tax Reduction schemes allow #2834's deduction, so I restated the awards in four cases of that YAML file. The deduction figures stay, since they still feed council_tax_reduction_applicable_income.
• Model rent from boarders, lodgers and sub-tenants for the householder #2002 and Deduct only the tax Council Tax Reduction schemes allow #2834 both rewrite the CTR tax deduction. It now lives in council_tax_reduction_tax_deduction, and with a working-age UC award it leaves out the tax the rent would bear without earnings.
• Deduct only the tax Council Tax Reduction schemes allow #2834 adds that deduction to the held list in test_means_tests_see_the_loss_only_through_tax. Hypothesis seeds a derandomized test from its source, so the edit draws new examples, and Run CI on 18 approved PRs merged together (not for merging) #2886 drew a Scottish mixed-age couple on UC with an award of 711.32 with the loss and nil without it. SSI 2021/249 reg 51 adds each trade's profit or loss, and the route follows it through UC's earnings, so I changed the test and left the model. The no-loss run now holds uc_individual_earned_income and uc_individual_earned_income_before_mif as it holds the award, along with the trade's part of the tax and the Welsh route's council_tax_reduction_working_age_unearned_income_tax.
• Model rent from boarders, lodgers and sub-tenants for the householder #2002 moves the boarder and lodger test to the person, and Give benefit-unit members aged 16 or over a bedroom under LHA rules #2010 adds non-dependants inside a benefit unit, so I restated cases in boarders_and_lodgers_non_dependants.yaml on four readings:
  • An in-unit adult counts in their own family's UC claim if it makes one, and otherwise in the claim that counts the household's other non-dependants. UC Sch 4 para 9(2)(f) sets no order, so the model chooses this one.
  • A lodger bears their own adult son in full, as the householder does. HB reg 3(2)(e)(i) excludes only the person liable to pay, and I read reg 3(2)(d) as keeping lodger and householder out of reg 74(5)'s apportionment.
  • A family's Pension Credit exempts its claimant or partner and not an adult son (Sch 4 para 16(2)(b); HB reg 74(10)).
  • A member who pays the householder counts in none of the three in-unit flags.
• Fix HB and national CTR non-dependant deductions #2007 gives each national Council Tax Reduction scheme its own deduction scale, and a case in Model rent from boarders, lodgers and sub-tenants for the householder #2002's boarders_and_lodgers_non_dependants.yaml still stated the Housing Benefit scale. At 300 a week, the son's deduction falls from 3,346.20 to 569.40 a year: Scotland's band from 286 takes 10.95 a week.
• Fix HB and national CTR non-dependant deductions #2007 exempts an adult on their own family's Universal Credit with no earned income (SI 2012/2885 Sch 1 para 8(8)(c)), and the model reads no award inside another family's unit. So Model rent from boarders, lodgers and sub-tenants for the householder #2002's property that a non-paying adult counts the same in or out of the payer's unit now gives that adult's own family no claim.
• Count UC carer awards for severe disability and Scottish CTR premiums #2827's veteran tests state a model with no UC Sch 4 para 15 exemption, and Give benefit-unit members aged 16 or over a bedroom under LHA rules #2010 brings one, so a blind single renter's deductions come to nil. The tests now supply that exemption as false wherever they expect the 1,158.60.
• Apply SI 2014/1230 reg 28 to the UC qualifying young person test #2845's first-day education test reads housing_benefit_report_is_rate_rebate_only, so Give benefit-unit members aged 16 or over a bedroom under LHA rules #2010's cycle test now allows any housing_benefit_report variable.
• Add CB and CTC qualifying young person routes for school leavers #2301 makes a 16-year-old outside education a Child Benefit qualifying young person. For a family at the London cap, her Child Benefit lowers Universal Credit by 897 (17.25 a week), so invariant 6 in Give benefit-unit members aged 16 or over a bedroom under LHA rules #2010's bedroom tests now covers people aged 20 or over.
• Guard against random draws in the engine #2873's guard scans the whole package, and Give UK simulations a working subsample #2265 brings the seeded draw behind Simulation.subsample, so the guard failed on utils/subsample.py. I added that file to EXEMPT, since it draws only when a caller asks for a sample and no formula reads the draw. No other entry there allows a draw, so please check that this one reads right to you.

#1966 and #2834 leave two readings of the tax on pay in place. #2834 deducts the tax the pay adds, and #1966 takes the UC split, with earnings as the lowest slice, so the Child Benefit charge no longer reaches a Scottish working-age award. I kept both here, and the difference needs its own decision.

Each fix moves into the real merge of whichever pull request in its pair lands second. #2828's head already carries its fixes for #1966's route, main's Step 6 order test and the 2019 row of the pensioner tariff table, and #2010's head carries every #2010 fix here except the one that needs #2827.

The run at 76392628b lost eight Python jobs about four minutes in, at 15.4 to 15.7 GB, and Test 6/7 at minute 51. The shards that finished failed only on the clashes above, and Release 2/7 passed. #2893 keeps the certified file on one shard, and this head carries it, so this run shows whether that stops the early losses.

Reproducer: policyengine_uk/tests/test_price_base_year.py::test_reform_changes_the_base_year

🤖 Generated with Claude Code

[MaxGhenis]

Both runs finished at 15:38Z. Every test that finished passed except one, and seven of the fourteen Python shards stopped before their tests finished.

Shard	Code changes	Versioning updates
YAML	passed	passed
Python 1	1,973 passed, then the job hit the 90-minute limit	1,883 passed
Python 2	cancelled at the 90-minute limit	cancelled at the 90-minute limit
Python 3	2,042 passed	1,958 passed
Python 4	1,964 passed, then the job hit the 90-minute limit	1,866 passed
Python 5	runner lost after 45 minutes	runner lost after 46 minutes
Python 6	runner lost after 8 minutes	runner lost after 69 minutes
Python 7	1 failed, 2,042 passed	1 failed, then cancelled at the 90-minute limit

Shard 7 failed test_income_related_esa_passports_to_the_full_liability in both runs. Hypothesis drew a Scottish couple aged 32 and 52 on income-related ESA, and the award came to £211.40 of a £500 liability. On #2010 the model presumes the younger of two adults at least 20 years apart to be the elder's child, who can then be a non-dependant. This branch holds #2010 from before d16a2e89c, which gives the property's families explicit roles. #2010 and #2828 merge cleanly on that test file, and the merge keeps #2010's roles and #2828's new invariant.

I'm closing this draft and deleting its branch.