RawBrowseCommitMapper.BuildTagConfig's unknown-driver fallback claimed to be
guarded by RawBrowseCommitMapperParityTests, which did not exist anywhere under
tests/. The claim it made — "every BROWSABLE driver is handled above" — is the
exact claim that stopped being true when SqlDriverBrowser registered (deferment.md
G-6), so the comment was asserting the invariant instead of pinning it.
The guard now exists and enumerates DriverTypeNames.All:
- Browsability's bespoke arm is DERIVED from production, not hand-listed: the test
runs AddAdminUI() and reads back every registered IDriverBrowser's DriverType —
the same set BrowserSessionService.CanBrowse indexes. A driver that gains or
loses a bespoke browser moves the guard with it.
- The universal arm (DiscoveryDriverBrowser -> ITagDiscovery) is NOT derivable from
the AdminUI assembly: it references driver Contracts/Browser projects, never the
runtime drivers, and IDriverFactory is composed in the Host. Covered instead by
requiring every declared driver type to be typed or explicitly exempted with a
reason (Modbus, Calculation), with a third fact mechanically refuting any
exemption the derived arm contradicts — the Sql failure mode.
Falsified three ways, each red naming the offender: disabling the Sql branch trips
the derived-arm fact; disabling the MTConnect branch trips the enumeration fact
(the universal-arm half, which no bespoke registration would have caught); adding
Sql to the exemption list trips the contradiction fact.
Comment corrected to state what the test actually asserts, including the residual
trust the universal arm leaves.
Joseph Doherty