endtoend: run the corpus through the analysis core with an opt-in context

[kyleconroy]

TestReplay runs the whole testdata corpus once per context: base as
committed, managed-db against a live database. This adds a third, core,
which generates every case through the analysis core, so the two paths can be
compared case by case rather than one case at a time.

The context

Contexts could only mutate config.Config, so the coreanalyzer experiment
could reach a case only through its own exec.json. textContext now also
names the experiments every case in it runs with:

type textContext struct {
	Mutate      func(*testing.T, string) func(*config.Config)
	Enabled     func() bool
	Experiments func() []string
}

A case's own SQLCEXPERIMENT is appended to the context's, so a case can still
turn one back off with the no prefix.

The two paths still disagree, so the context is opt-in, and needs no database:

SQLC_TEST_CORE=1 go test ./internal/endtoend -run 'TestReplay/core'

The gate is an environment variable rather than a test flag because the
documented workflow runs the whole module, and a flag defined in one test
binary fails every package that does not define it:

$ go test -run TestNothingMatches -update=true ./internal/sql/preprocess ./internal/opts
flag provided but not defined: -update

It also matches how the rest of this suite is configured — POSTGRESQL_SERVER_URI,
MYSQL_SERVER_URI, SQLC_DUMMY_VALUE.

The panic it found

Two cases took the test binary down, which ended the run partway through and
took the rest of the corpus with it. A set-returning function in FROM takes
its arguments from the items before it, so bindRangeFunction types the call
while the scope is still being assembled — but the scope under construction was
never installed on the analyzer, so a.scope was nil and resolving one of those
arguments dereferenced it:

FROM transactions,
     jsonb_each(jsonb_extract_path(transactions.data, '...')) AS instructions

buildScope and relationScope now install the scope they are filling for as
long as they fill it, and put back the one they replaced on the way out.
Resolving against a nil scope also reports the column as unresolved rather than
crashing, so no other half-built statement can panic on the way to the error it
was going to report anyway.

Both queries now analyze to an ordinary error, and the core context runs to
completion in a single process.

Worth a look on review: installing the partial scope also means a FROM item
can now resolve columns from the items before it, which is what
bindRangeFunction's comment always claimed it did. That is a small
permissiveness increase for subqueries in FROM — a non-LATERAL subquery can
now see an earlier FROM item. Nothing in the suite depends on the stricter
behavior, but it is a semantic change rather than a purely defensive one.

Where the paths differ today

838 cases run under core, 311 pass, 527 fail. Ranked:

Count	Divergence
224	* not expanded in the emitted SQL
121	other generated-code differences
99	hard errors, sqlc generate exits non-zero
22	nullability (sql.Null* / pgtype wrappers)
15	column or param typed interface{}
10	enum scaffolding missing from models.go
7	stderr differs — both paths error, different message
6	integer signedness (MySQL uint vs int)
4	array/slice-ness

Star expansion is one behavior and 43% of the failures. Of the hard errors, 47
are illegal character U+003F '?' — parameters get dropped, so the emitted Go
does not compile — then catalog sql: no rows in result set on CTEs and
schema-qualified relations, unsupported AST nodes (*ast.NamedArgExpr,
*ast.MultiAssignRef), and unknown column on unnest.

No goldens were regenerated and no divergence was papered over. The failures are
the report.

Testing

• go test --tags=examples -timeout 20m ./... passes with PostgreSQL and MySQL
  live — 31 packages, no failures. Covers base, managed-db, and the
  live-database example tests.
• SQLC_TEST_CORE=1 go test ./internal/endtoend -run 'TestReplay/core' completes
  in one process with zero panics.
• Nothing changes for anyone who does not set SQLC_TEST_CORE.

🤖 Generated with Claude Code

https://claude.ai/code/session_0161e7oMkzNW9DZMUPtyQibH

---

Generated by Claude Code