EF Core mapping sweep: schema parity with EF Core migrations (tables + indexes)

[jeremydmiller]

What this is

A comprehensive sweep of Weasel.EntityFrameworkCore's DbContext → Weasel table mapping. It adds a dual-schema comparison harness that, for a matrix of EF Core mapping permutations, verifies at the database-catalog level that the schema Weasel creates is identical to what EF Core's own migration system creates — and that Weasel's delta detection reports zero changes against an EF-created schema (and against its own, for idempotency). Everything the harness exposed is fixed here.

See EFCORE_IMPROVEMENTS.md (repo root) for the full write-up.

Bugs found & fixed (all pre-existing on master)

1. PostgreSQL identifier casing — EF emits quoted PascalCase; Weasel folded to lowercase, so EF couldn't insert into Weasel-created tables. can_apply_migration_with_fk_dependencies was failing on master because of this. New opt-in ITable.PreserveIdentifierCase seam + quoted PK/FK/index DDL + case-insensitive delta matching. All-lowercase callers (Marten) emit byte-identical DDL as before.
2. No index mapping — Weasel dropped EF's indexes. EF creates IX_* indexes for every FK by convention; Weasel's delta emitted DROP INDEX for them. New provider-neutral ITableIndex / ITable.AddIndex (all five providers); the mapper maps HasIndex (unique/composite/named/filtered/INCLUDE), conventional FK indexes, and alternate keys.
3. HasDefaultValue literals silently dropped — now rendered via EF's own GenerateSqlLiteral (bool/string/Guid/DateTime/enum incl. conversions).
4. Delete behaviors — ClientSetNull (EF's default for optional FKs) wrongly produced ON DELETE SET NULL; all Client* behaviors now map to no action. SQL Server normalizes Restrict ≡ NO ACTION.
5. No identity mapping — Weasel-created int-key tables broke EF inserts. ITableColumn.IsAutoNumber + PostgreSQL GENERATED BY DEFAULT AS IDENTITY emission, with correct suppression for defaults, TPT linking keys, and non-integral types.
6. SQL Server introspection — INCLUDE columns were read as key columns (endless covering-index churn); rowversion/timestamp synonym; FK parsing left quote chars in names.

Plus mapper correctness: TPH nullability via IsColumnNullable, table-split owned entity columns, owned-with-own-table inclusion (over-fix of #234), row-internal FK skip.

Test coverage

19 comparison suites (14 PostgreSQL, 5 SQL Server): defaults, composite keys, indexes (incl. SQL Server's automatic IS NOT NULL filter on unique-nullable indexes), alternate keys, many-to-many, self-reference + delete-behavior matrix, TPH, TPT, owned entities, facets, identity strategies, rowversion, check constraints (documented gap). Known gaps are each pinned by a test or tolerated diff category.

Infrastructure

• New ci-build-efcore.yml — the EF Core test project previously ran in no CI workflow at all (how a failing test sat on master unnoticed).
• End-to-end tests no longer EnsureDeleted the shared marten_testing/weasel_testing databases (they were killing concurrent tests' connections with 57P01).
• TestTfmsInParallel=false + xunit collections for schema-sharing classes and Azure SQL Edge DDL deadlocks.

Verification

• EF suite: 56/56 (net9.0) + 58/58 (net10.0)
• Regressions: Weasel.Postgresql.Tests 762 ✅, Weasel.SqlServer.Tests 299 ✅, Weasel.Sqlite.Tests 361 ✅, Weasel.Core.Tests 21 ✅
• Full solution builds clean on all TFMs

🤖 Generated with Claude Code