Documentation, one new validation rule, and test coverage on top of wsman's
GitHub PR #6. No change to what _defensive itself does.

conn.go: the comment above the db_config calls had been generalized to
"connection-level sqlite3_db_config options are applied before
applyQueryParams because the SQLite contract requires
sqlite3_db_config(SQLITE_DBCONFIG_DQS_*) to be set before any statement is
prepared". That contract is DQS-specific and does not extend to DEFENSIVE,
which may be toggled at any point in a connection's life; defensive goes
first because the PRAGMAs that follow must run under the restriction, which
is a choice, not an API requirement. Restore the DQS comment verbatim on the
DQS call and give _defensive its own rationale.

sqlite.go: reject _defensive=1 together with _journal_mode=OFF (or
_journal=OFF). SQLite turns PRAGMA journal_mode=OFF into a no-op that still
reports success under defensive mode, so the combination previously opened ...

TestConcurrentGoroutines re-invokes itself under -race and treats anything
the recursive run prints other than two known "cannot run here" messages as a
failure. With CGO_ENABLED=0 the go tool refuses with "-race requires cgo;
enable cgo by setting CGO_ENABLED=1", which matched neither, so the whole
suite failed on an environment where the check simply cannot run -- and a
CGo-free driver is a natural thing to build and test with cgo disabled.
Accept that message alongside the existing two and skip, as the test already
does for a toolchain without race support and for an unsupported VMA range.
Nothing changes when cgo is available: the recursive -race run still executes
and still has to pass.

Found while reviewing GitHub PR #6, whose author hit it in a CGO_ENABLED=0
lane; unrelated to that change.

Deln0r has had Maintainer rights on the GitLab project since 2026-06-09.
The file has named only me since it was added in February and predates
that grant.

Split out of !135, where the hunk was proposed alongside a code change.

vec/ has carried the transpiled sqlite-vec sources since v1.47.0, but the
module shipped only its own BSD-3-Clause LICENSE and the public-domain SQLite
notice. sqlite-vec is Copyright (c) 2024 Alex Garcia and dual-licensed
Apache-2.0 OR MIT; modernc.org/libsqlite_vec's generator elects MIT, whose
terms require the copyright and permission notice to accompany substantial
portions of the software. 2.8 MB of transpiled vec/ is a substantial portion.
Attribution was never absent -- vec's package documentation names the
extension, pins v0.1.9 and links upstream -- but the license text was.

LICENSE-SQLITE_VEC: the notice, byte-identical to LICENSE-MIT in the upstream
v0.1.9 archive and to the file libsqlite_vec extracts it into.

vendor_libs/main.go: the omission was mechanical -- the tool copied the
per-target transpiles and nothing else, so a plain cp of the notice would have
survived only until the next `make vendor`. Copy it alongside the sources it
belongs to, and treat a missing source as fatal: shipping the code without the
notice is worse than not vendoring at all.

SQLITE-LICENSE -> LICENSE-SQLITE, contents unchanged. This matches the new file
beside it and the LICENSE-<upstream> convention the rest of the modernc.org
repositories follow, but it is not only cosmetic. `go mod vendor` picks the
metadata files it copies into a downstream vendor/ tree by matching each name
against a fixed prefix list (cmd/go/internal/modcmd/vendor.go, metaPrefixes)
that includes LICENSE, so a name merely ending in LICENSE was never propagated.
Both notices now reach vendored builds, which is where the MIT terms on vec/
keep applying. Direct links to the old path will break.

vec/patches.go: a License section on the package documentation, so an importer
of vec sees on pkg.go.dev that this package is under a different license from
the rest of the module.

Found by an SBOM audit of the published module.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

The vendoring reads one full per-target file at a time from ../libsqlite3 and
../libsqlite_vec, which assumes those checkouts ship expanded. They do today,
but either may adopt the deduplicated layout that modernc.org/wa2c already ships
(modernc.org/builder's NW autogen; see NW_GENERALIZATION_HANDOFF.md there) — and
then those per-target files hold only each target's residue, so vendoring them
would silently drop most of the package.

Detect it instead of remembering it later. srcDir applies undup's own rule
(base.go or base_g_*.go present means folded) and:

  - returns an expanded checkout as is: no copy, no subprocess, exactly the path
    this tool has always taken;
  - copies a deduplicated one to a temp directory and expands it THERE, never in
    place — expanding the sibling would leave that checkout dirty and tempt a
    "restore" that discards whatever else is uncommitted in it. go.mod and go.sum
    travel with the copy be...

TestDBPageVtab's comment about -DSQLITE_ENABLE_DBPAGE_VTAB carried a trailing
space, which made all_test.go the one hand-written file in the tree that
gofmt -l reports. Comment text only; nothing else changes.

Noticed by Ian Chechin while preparing GitLab merge request #135, which does
not touch this file.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

The test registered its driver under the fixed name "sqlite_conn_hook_test".
sql.Register panics on a name it has already seen and offers no way to undo a
registration, so the second iteration of go test -count=2 took the whole test
binary down with "sql: Register called twice for driver
sqlite_conn_hook_test" -- not a failure of the code under test, and it hid
whatever the remaining iterations would have found.

Derive the name from an atomic counter instead, so each invocation registers
its own driver, and close the sql.DB the test opens while here: it was leaked
once per iteration.

Nothing changes for a single run. Ian Chechin's driver_register_test.go in
GitLab merge request #135 solves the same problem with a uniqueDriverName
helper; the two can be folded together once that lands.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Driver holds four categories of registration state but only connection
hooks could be put on a constructed one. Functions and collations were
reachable through the package-level API alone, and modules through the
package-level driver only, so a constructed Driver was half-built: its
modules field was written and read through the package-level instance,
making it process-global state wearing a per-instance field.

This is the additive half of #254, with one narrow, loud exception
spelled out below:

  - registerFunction and registerCollation become methods on *Driver.
    The package-level RegisterFunction, RegisterScalarFunction,
    RegisterDeterministicScalarFunction and RegisterCollationUtf8 keep
    targeting the package-level driver, spelled explicitly now rather
    than by relying on the receiver named d shadowing the package
    variable of the same name. newDriver is renamed defaultDriver,
    since it read...

sqlite: let a caller-constructed Driver register its own functions, collations and modules

See merge request !135

All three shipped as experimental in v1.53.0 and were deliberately left out
of the supported platforms table until they had accumulated some real-world
exposure. That period has elapsed: they have been in the builder matrix and
in build_all_targets since, they pass on this release's commit alongside the
seventeen platforms already listed, and no open issue reports a defect in any
of them. The table therefore listed seventeen entries while the module
shipped, cross-built and tested twenty; it now lists all twenty.

Also set the v1.57.0 CHANGELOG date to the release date, and drop a stale
claim in lib/hooks_linux_arm64.go that this module is "stuck on libc@v1.55.3"
-- go.mod has pinned v1.74.4 since v1.56.0. The comment now says what the
run-time patch is actually for.

The C side of #255 ships in the
transpiled SQLite 3.53.4 sources: opt-in, off by default, process-wide,
frozen at the process's first lock attempt, with a latched POSIX fallback
on kernels that reject F_OFD_*. This adds the Go-facing half: OFDLocking
switches the mode (overriding MODERNC_SQLITE_OFD_LOCK) and
OFDLockingEnabled reports it, with ErrOFDLockingTooLate and
ErrOFDLockingUnavailable mapping the gate's refusals. The scenario tests
from merge request !136 now run in a re-executed child process with the
mode really on (and the both-modes invariants also in the parent's
inherited mode), TestOFDLockingSetter covers the Go call path end to end
against /proc/locks, and the other platforms assert the switch reports
itself unavailable.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qsot8zfLpqv4jHfpRgEq94

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qsot8zfLpqv4jHfpRgEq94