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The publishability gate caught internal tooling names and developer paths but nothing site-specific, so roughly sixty leaks reached the wiki: the site name in ten documents, real fleet hostnames in the collector and GE-Enforce examples, an internal database name through the whole import guide, imaging-share paths, and a maintainer's username as the Deciders line of every ADR and inside a generated curl example. None of it is a security matter on an air-gapped fleet. It matters because these pages are read by engineers at other plants, and a document that names one site throughout reads as that site's notes rather than a product's documentation - which is exactly what it then gets treated as. Examples now use neutral hostnames, the site is "the reference site" where the distinction carries meaning, and ADRs are decided by "ShopDB maintainers". The gate carries all of these patterns, so the next one fails a build. Two documents leave docs/ because they were never written for an outside reader. PROJECT-REVIEW.md is an internal health memo pinned to a commit from July, whose headline finding (an untracked playbook) has since been fixed - it is history, and git holds it. PILOT-DEPLOY.md is one site's own cutover runbook, complete with a "re-measure before publishing" placeholder; it moves next to the loader it belongs to, in scripts/site_imports/wjf/. ADR-015 is AMENDED rather than rewritten. Its enforcement section still said report-only and its backlog still listed hardcodes that are now cleared, which left the record contradicting itself. The amendment says what changed and why the report-only period ended; the original text stays, because what the decision looked like when it was taken is the part worth keeping. Also corrects llms.txt's response envelope, which had errors at the top level and pagination at meta.total. Both are nested one deeper, so anything written against that description read undefined on every error it tried to handle.
124 lines
6.3 KiB
Markdown
124 lines
6.3 KiB
Markdown
# ADR-008: Plugin migration ownership (per-plugin chains from the cutover)
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- **Status:** ACCEPTED
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- **Date:** 2026-07-10
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- **Deciders:** ShopDB maintainers
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- **Supersedes:** the "Migration strategy (resolved)" section of ADR-004
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## Context
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ADR-004 resolved a Phase 7B footgun by folding every bundled plugin's tables
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into the single core Alembic chain (migration `7c04_fold_plugin_schema`), and
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later core migrations (`7d04`..`7d16`) kept adding plugin schema directly to the
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core chain. At the time this was the safe choice: bundled-plugin baselines and
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the core baseline had both been creating the same tables, so
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`flask plugin upgrade-all` would collide with `flask db upgrade`.
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That resolution left the per-plugin Alembic engine
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(`shopdb/plugins/migrations.py`, `shopdb/plugins/alembic_template.py`, the
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`alembic_version_<plugin>` version tables, and `flask plugin upgrade-all`) fully
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built but unused for the bundled plugins. The framework is the product (per the
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project's charter); a plugin that cannot own its own schema is not really a
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plugin. Sister sites that adopt or fork a plugin need its schema history to
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travel with the plugin, not be entangled in the host's core chain. Keeping every
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future plugin table change in the core chain also means the core chain grows
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without bound and a plugin can never be cleanly removed.
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The blocker ADR-004 worried about (double table creation) only exists while a
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plugin's own migration tries to CREATE tables the core chain already created.
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That is avoidable: history is immutable, so the tables already built by the core
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chain stay owned by the core chain; only NEW schema needs a new home.
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## Decision
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Ownership splits at a fixed cutover, the current core-chain head.
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1. **Core chain owns history through its head.** The core Alembic chain
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(baseline `68b3947ae14f` .. head `7d16_directoryemployees`) remains
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authoritative for every table that exists at the cutover, including the
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bundled-plugin tables it created. Those migrations are immutable and are not
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rewritten. `flask db upgrade` continues to reproduce the full schema.
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2. **Plugin chains own plugin schema going forward.** From the cutover forward,
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any change to a plugin's schema lands as
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`plugins/<name>/migrations/versions/000N_*.py` in that plugin's own chain,
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never in the core chain. The core chain is reserved for core tables.
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3. **Every table-owning bundled plugin gets a `0001` anchor.** Each such plugin
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carries a migration chain whose first revision is a stamp-only no-op:
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`upgrade()` does nothing because the core chain already created the tables.
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The anchor exists so the plugin chain has a base that
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`flask plugin upgrade-all` can stamp into the per-plugin version table
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`alembic_version_<plugin>`. Blueprint-only plugins that own no tables get no
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chain.
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4. **Deploy and upgrade sequence.** A deploy runs `flask db upgrade`
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(core chain, creates everything through the head) then
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`flask plugin upgrade-all` (stamps every plugin anchor and applies any later
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per-plugin migrations). The same two commands upgrade an existing install;
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both are idempotent. The registry (`instance/plugins.json`) tracks each
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plugin's applied revisions in `migrations_applied`.
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5. **Table-ownership registry.** `PLUGIN_TABLE_OWNERS` in
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`shopdb/plugins/alembic_template.py` is the explicit map of which tables each
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plugin owns; it is kept in sync with the plugins' `__tablename__` declarations
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and pinned by `tests/test_plugin_migrations.py`.
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External (out-of-tree) plugins per ADR-003 already shipped their own chains;
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this ADR brings the bundled plugins onto the same model, so there is one rule
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for all plugins.
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## Consequences
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### Positive
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- A plugin's schema history travels with the plugin. Adopting or forking sites
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get the plugin's migrations, not a slice of someone else's core chain.
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- The core chain stops accreting plugin schema; it stays about core tables.
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- A plugin can be evolved (or, with its own downgrade, removed) independently.
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- The long-built per-plugin Alembic engine is finally exercised on every deploy,
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so it cannot silently rot.
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### Negative / cost
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- Two migrate commands per deploy instead of one. Documented in `docs/DEPLOY.md`
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and `docs/UPGRADE.md`; both are idempotent so the cost is one extra safe call.
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- A plugin author must now put new tables in the plugin chain and register them
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in `PLUGIN_TABLE_OWNERS`, rather than autogenerating into the core chain. The
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`flask plugin new` guidance and this ADR spell that out.
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- The cutover is a discontinuity: tables created before it are core-owned,
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tables created after it are plugin-owned. The line is the core-chain head at
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this ADR's date, recorded here so it is unambiguous.
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### Neutral
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- No schema changes and no data migration: the anchors are no-ops. A fresh
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install and an existing install converge to the same state.
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## Alternatives considered
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1. **Keep everything in the core chain (status quo per ADR-004).** Simplest
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operationally but defeats the plugin-as-product goal: plugin schema cannot
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travel, the core chain grows without bound, and plugins can never be cleanly
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removed. Rejected.
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2. **Rewrite history so plugin tables move out of the core chain into plugin
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`0001` CREATE migrations.** Would make each plugin chain self-contained from
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empty, but breaks the immutability rule, forces every existing site to
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re-run a rewritten chain, and re-introduces the exact double-creation footgun
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ADR-004 fixed. Rejected.
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3. **Anchor that CREATEs tables with `IF NOT EXISTS` guards.** Lets a from-empty
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install build plugin tables from the plugin chain, but then two chains both
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claim the same tables and drift can diverge silently. The no-op anchor keeps
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a single authoritative creator (the core chain) for cutover-era tables.
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Rejected.
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## References
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- ADR-003 (plugin distribution; external plugins already ship chains)
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- ADR-004 (deployment topology; this ADR supersedes its migration-strategy note)
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- `shopdb/plugins/alembic_template.py` (`PLUGIN_TABLE_OWNERS`, shared env runner)
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- `shopdb/plugins/migrations.py`, `shopdb/plugins/cli.py` (`upgrade-all`)
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- `plugins/<name>/migrations/` (per-plugin chains and `0001` anchors)
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- `tests/test_plugin_migrations.py` (ownership + chain + idempotency guards)
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- `docs/DEPLOY.md`, `docs/UPGRADE.md`, `docs/PLUGINS.md` (deploy sequence)
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