[CaffeinatedCoder]

Closes #197

Into release/5.x. Found by the focused 5.6.0 sweep (round-trip lens). It has been present since temporal foreign keys shipped; it isn't a 5.6.0 regression. Closes acts only on main, so #197 is closed by hand after the merge.

Problem

A temporal foreign key whose principal is a generic entity type (Room<int>) couldn't be diffed from its migration snapshot. The declaration stores the principal as typeof(TPrincipal).FullName, which is …Room`1[[System.Int32, …]], while EF names the entity type …Room<int>. The live model matched through ClrType.FullName. A snapshot's property-bag type has ClrType == Dictionary<string, object>, so ResolveEntityType found nothing and threw. The first migrations add passed. Every later one, has-pending-model-changes, and Migrate()'s pending-changes check failed, even with no change. It also hid the snapshot path of #187/#188's tests, which use generic types.

Change

• EntityTypeNames.FromClrFullName (new, internal, PostgreSQL package) converts a CLR FullName to EF Core's entity-type name, following SharedTypeExtensions.DisplayName(fullName: true) in EF Core 10: keywords for built-in types, T? for Nullable<T>, each segment of a nested generic type with its own arguments, and array ranks as written. Input it can't read comes back unchanged.
• ResolveEntityType matches the stored name, its EF form, or the CLR FullName.
• Stored names are unchanged. Snapshots already hold the FullName form, and writing another would rewrite them.

Also: a ### Fixed line in the root and PostgreSQL changelogs, and CLAUDE.md.

Tests

• SnapshotRoundTripTests.Temporal_foreign_key_to_a_generic_principal_roundtrip_is_noop: a temporal FK to RoundTripGenericRoom<int>, diffed from its Roslyn-compiled snapshot against the unchanged model, yields no operations.
• EntityTypeNameTests: EF's own model is the oracle. For 11 shapes the conversion of type.FullName equals the name ModelBuilder.Entity(type) gives: non-generic, Generic<int>, <string>, <Guid>, <int?>, <int[]>, <List<long>>, <Generic<bool>>, Pair<int, string>, Pair<DateOnly?, Plain>, and Outer<int>.Inner.
• With the ResolveEntityType change reverted: the snapshot test fails with "Could not resolve temporal foreign key principal entity …Room`1[[System.Int32…".
• Suites: unit plus PostgreSQL 18/16, 746 passed.

🤖 Generated with Claude Code