docs: decide to build our own store and delete the vendored provider

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The vendored dmfs provider was kept on the grounds that it hands us the
sync bookkeeping for free. The phase-1 sync audit measured that
bookkeeping and found most of it broken, absent, or unusable: _DIRTY not
set on delete, no home for a per-collection sync token, read-only
collections inexpressible, ACCOUNT_TYPE write-once so enabling sync is a
full migration, and cleanUpLists able to delete a user's lists after a
backup restore. Sixteen findings are provider-imposed rather than
platform- or protocol-imposed.

Costing the alternative showed the swap is far smaller than assumed.
TasksDataSource is already a 14-method, domain-shaped interface;
exactly one file above the data layer references TasksContract. The
work is a second implementation behind an interface built for it, not a
rewrite. Against ~5 weeks to build, owning the store removes 2.5-4
weeks from the sync plan, and 8,200 of the vendored 14,555 lines are
things we would never write - 23 migrations from a 2013 schema, 798
lines of full-text search the app has zero call sites for, and 1,581
lines of a type-safe layer over ContentValues that Room deletes.

External mode (OpenTasks, tasks.org) is unaffected and keeps every
file that describes somebody else's schema.

STORAGE-DECISION.md is the reasoning; OWN-STORE.md is the architecture
and the six-phase plan. :provider stays in-tree until phase 5 so
recurrence parity can be tested against it before it goes.

Also corrected here: the provider's JVM test count (51 -> 56, measured
from the test-results XML) and a fourth site of the debunked "switching
sync on is never a migration" claim, in StorageMode.kt.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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This commit is contained in:

Jean-Luc Makiola

2026-08-13 14:46:07 +02:00

parent 98ed339346

commit 13cb27b2ab

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