Update Black to 2026 Stable Style

[jperson1]

Update Black to 2026 Stable Style

What's the Big Idea?

Black is our primary Python linter. Every January, any breaking changes are included in the yearly stable release. See 26.1.0 here.

There is one rule change that affects a huge amount of our files. It always forces one blank line after import statements. We have historically always used two. So, there's a lot of one line changes here. Please see some of the discussion from the offending PR here, for a little more context on the why of this change.

TL;DR: Black focuses on consistency over malleability (and readability sometimes). They hadn't made a decision on the number of lines post-import, and now they have. So, here it is. I'm inclined to follow it, in the name of keeping all open-source (us) projects in line with each other.

This does lead many files to a strange-ish pattern. Imports -> One line -> Logger/assignment -> Two lines -> Function. Since functions are surrounded by two lines, this is consistent with the rules. It just looks weird after all this time, when the logger is closer to the imports instead of being quarantined on both sides.

Other Changes:

1. There's a multi-line string fix. This is not really impactful.
2. Left-hand multi-assignments have had their unnecessary parenthesis removed. That's a fun sentence to say.

PR Checklist: Submitter

• Link to an issue if possible. If there’s no issue, describe what your branch does. Even if there is an issue, a brief description in the PR is still useful.
• List any special steps reviewers have to follow to test the PR. For example, adding a local environment variable, creating a local test file, etc.
• For extra credit, submit a screen recording like this one.
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• Make sure you’ve accounted for any migrations. When you’re about to create the PR, bring up the application locally and then run git status | grep migrations. If there are any results, you probably need to add them to the branch for the PR. Your PR should have only one new migration file for each of the component apps, except in rare circumstances; you may need to delete some and re-run python manage.py makemigrations to reduce the number to one. (Also, unless in exceptional circumstances, your PR should not delete any migration files.)
• Make sure that whatever feature you’re adding has tests that cover the feature. This includes test coverage to make sure that the previous workflow still works, if applicable.
• Make sure the full-submission.cy.js Cypress test passes, if applicable.
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• Ensure that prior to merging, the working branch is up to date with main and the terraform plan is what you expect.

PR Checklist: Reviewer

• Pull the branch to your local environment and run make docker-clean; make docker-first-run && docker compose up; then run docker compose exec web /bin/bash -c "python manage.py test"
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The larger the PR, the stricter we should be about these points.

Pre Merge Checklist: Merger

• Ensure that prior to approving, the terraform plan is what we expect it to be. -/+ resource "null_resource" "cors_header" should be destroying and recreating its self and ~ resource "cloudfoundry_app" "clamav_api" might be updating its sha256 for the fac-file-scanner and fac-av-${ENV} by default.
• Ensure that the branch is up to date with main.
• Ensure that a terraform plan has been recently generated for the pull request.

[github-actions]

Terraform plan for meta

No changes. Your infrastructure matches the configuration.

No changes. Your infrastructure matches the configuration.

Terraform has compared your real infrastructure against your configuration
and found no differences, so no changes are needed.

✅ Plan applied in Deploy to Development and Meta Environments #1092

[github-actions]

Terraform plan for dev

Plan: 1 to add, 0 to change, 1 to destroy.

Terraform used the selected providers to generate the following execution
plan. Resource actions are indicated with the following symbols:
-/+ destroy and then create replacement

Terraform will perform the following actions:

  # module.dev.module.cors.null_resource.cors_header must be replaced
-/+ resource "null_resource" "cors_header" {
!~      id       = "*******************" -> (known after apply)
!~      triggers = { # forces replacement
!~          "always_run" = "2026-01-26T19:28:02Z" -> (known after apply)
        }
    }

Plan: 1 to add, 0 to change, 1 to destroy.

✅ Plan applied in Deploy to Development and Meta Environments #1092

[jperson1]

Everything seems to be in order. Undrafting.

[ccampbell-fearless]

LGTM

[phildominguez-gsa]

Looks fine, and I ran full-submission for fun

[github-actions]

Package	Line Rate	Branch Rate	Health
.	100%	100%	✔
api	98%	86%	✔
api.serializers	97%	88%	✔
api.views	91%	100%	✔
audit	95%	81%	✔
audit.cross_validation	97%	86%	✔
audit.fixtures	84%	50%	❌
audit.formlib	36%	0%	❌
audit.intakelib	89%	83%	➖
audit.intakelib.checks	92%	85%	✔
audit.intakelib.common	98%	82%	✔
audit.intakelib.transforms	100%	95%	✔
audit.management.commands	78%	17%	❌
audit.migrations	100%	100%	✔
audit.models	91%	68%	✔
audit.templatetags	100%	100%	✔
audit.views	72%	49%	❌
census_historical_migration	96%	65%	✔
census_historical_migration.migrations	100%	100%	✔
census_historical_migration.sac_general_lib	92%	84%	✔
census_historical_migration.transforms	95%	90%	✔
census_historical_migration.workbooklib	68%	69%	❌
config	78%	37%	❌
curation	98%	100%	✔
curation.curationlib	88%	72%	➖
curation.migrations	100%	100%	✔
dissemination	89%	70%	➖
dissemination.analytics	27%	0%	❌
dissemination.forms	80%	30%	❌
dissemination.migrations	97%	25%	✔
dissemination.models	100%	100%	✔
dissemination.report_generation	21%	0%	❌
dissemination.report_generation.excel	32%	0%	❌
dissemination.searchlib	62%	45%	❌
dissemination.templatetags	48%	0%	❌
dissemination.views	67%	44%	❌
djangooidc	53%	38%	❌
djangooidc.tests	100%	94%	✔
report_submission	100%	96%	✔
report_submission.migrations	100%	100%	✔
report_submission.templatetags	74%	100%	❌
report_submission.views	78%	61%	❌
support	94%	75%	✔
support.migrations	100%	100%	✔
support.models	90%	50%	➖
tools	98%	50%	✔
users	95%	86%	✔
users.fixtures	100%	83%	✔
users.management	100%	100%	✔
users.management.commands	100%	100%	✔
users.migrations	100%	100%	✔
Summary	88% (21837 / 24718)	69% (2681 / 3900)	➖

Minimum allowed line rate is 85%