regclass cast does not strip quoted-identifier syntax — '"name"'::regclass silently resolves to NULL #191

Version / build tested against

origin/main @ eea86b279

Deployment mode

Origin — single node (local)

Engine(s) involved

Not engine-specific / unsure

Summary

The virtual pg_catalog's regclass cast only resolves bare relation names. A quoted-identifier literal — '"g_probe"'::regclass — is not unquoted before lookup and silently resolves to NULL, so catalog queries filtered on it return 0 rows. PostgreSQL strips the double quotes and resolves the relation; standard client libraries and ORMs quote defensively and emit exactly this form for their schema-reflection queries, which therefore silently return nothing. Secondary symptom: a bare SELECT 'name'::regclass renders an empty cell in both quoting forms (PostgreSQL renders the relation name), though the unquoted cast works as a join/filter value.

Steps to reproduce

-- fresh data directory, psql on 6432
CREATE COLLECTION bug042_probe (id BIGINT PRIMARY KEY, name TEXT DEFAULT 'x', qty INT)
  WITH (engine = document_strict);

-- unquoted form: works as a filter
SELECT attname FROM pg_attribute WHERE attrelid = 'bug042_probe'::regclass;
--  id / name / qty  (3 rows)

-- quoted-identifier form (what defensive clients emit): silently matches nothing
SELECT attname FROM pg_attribute WHERE attrelid = '"bug042_probe"'::regclass;
-- (0 rows)            -- expected: same 3 rows

-- bare cast renders empty in both forms
SELECT 'bug042_probe'::regclass;
-- (1 row, empty cell)  -- expected: bug042_probe

Expected behavior

'"name"'::regclass unquotes the identifier and resolves like 'name'::regclass (PostgreSQL semantics: double quotes stripped, case preserved). Bare SELECT ...::regclass renders the relation name.

Actual behavior

Quoted form silently resolves to NULL — filtered catalog queries return 0 rows with no error. Bare cast renders an empty cell in both forms.

What actually happened? (check all that are true)

• A workaround exists (rewrite the query, avoid one path, etc.)

Proposed severity

SEV-2 — High: silently-empty catalog results for the quoting standard clients emit; stored data intact. (Workaround — emit the unquoted form — is available to hand-written SQL but not to stock client libraries.)

Reproducibility

Always — every attempt

Last known-good version / commit (if a regression)

(blank — never worked; the surrounding catalog tables became queryable on 3eaa49873)

Environment & logs

Linux x86_64, release build.

Before submitting

• I searched existing issues and this is not a duplicate.
• I reproduced this on a released tag or a current main build (not a stale local branch).
• This is not a security vulnerability (those go to a private advisory).