Make riverdriver/riverpgxv5 its own submodule

Here, make `riverdriver/riverpgxv5` its own submodule. This does nothing
for the time being since the top-level River package is entirely
dependent on `riverpgxv5` as the only driver (and its used in examples
and tests), but the general idea is that in the future each driver could
bring in its own dependencies, and applications using River wouldn't
have to pull in every 3rd party database package that River supports.

The only problem is that there's a tradeoff: the way I had `riverpgxv5`
before is that it referenced `riverdriver.Driver` and made use of an
`internal.Sentinel` value from the top-level package to guarantee no one
could implement the driver interface externally. That no longer works
because it introduce a dependency cycle: `river` needs `riverpgxv5` and
`riverpgxv5` needs `river`. So I can remove the top-level types
referenced in `riverpgxv5` so the dependency only goes one way, but we
lose `internal.Sentinel`, and can no longer guarantee that `Driver`
isn't implemented.

So put simply: `riverpgxv5` gets its own module, but we move to only a
soft guarantee that external users don't implement `Driver` (we spell it
out in the docs, but there's nothing technical preventing people from
doing it).

Overall: I think it's probably worth it. It's pretty clear `Driver`
isn't meant for external implementation, there's no advantage to doing
so, and the interface is already a little leaky because users could
technically call functions on the interface already like `GetDBPool()`
and break themselves as those disappear in the future.

go.mod

@@ -1,12 +1,13 @@
 module github.com/riverqueue/river
 
-go 1.21
+go 1.21.0
 
 require (
 	github.com/jackc/pgerrcode v0.0.0-20220416144525-469b46aa5efa
 	github.com/jackc/pgx/v5 v5.5.0
 	github.com/jackc/puddle/v2 v2.2.1
 	github.com/oklog/ulid/v2 v2.1.0
+	github.com/riverqueue/river/riverdriver/riverpgxv5 v0.0.0-00010101000000-000000000000
 	github.com/robfig/cron/v3 v3.0.1
 	github.com/spf13/cobra v1.8.0
 	github.com/stretchr/testify v1.8.4
@@ -24,7 +25,9 @@ require (
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rogpeppe/go-internal v1.10.0 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
-	golang.org/x/crypto v0.9.0 // indirect
-	golang.org/x/text v0.9.0 // indirect
+	golang.org/x/crypto v0.15.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
+
+replace github.com/riverqueue/river/riverdriver/riverpgxv5 => ./riverdriver/riverpgxv5

go.sum

@@ -40,14 +40,14 @@ github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcU
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
 go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
-golang.org/x/crypto v0.9.0 h1:LF6fAI+IutBocDJ2OT0Q1g8plpYljMZ4+lty+dsqw3g=
-golang.org/x/crypto v0.9.0/go.mod h1:yrmDGqONDYtNj3tH8X9dzUun2m2lzPa9ngI6/RUPGR0=
+golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
+golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
 golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1 h1:k/i9J1pBpvlfR+9QsetwPyERsqu1GIbi967PQMq3Ivc=
 golang.org/x/exp v0.0.0-20230522175609-2e198f4a06a1/go.mod h1:V1LtkGg67GoY2N1AnLN78QLrzxkLyJw7RJb1gzOOz9w=
 golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
 golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/text v0.9.0 h1:2sjJmO8cDvYveuX97RDLsxlyUxLl+GHoLxBiRdHllBE=
-golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
 gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

riverdriver/river_driver_interface.go

@@ -15,8 +15,6 @@ package riverdriver
 import (
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
-
-	"github.com/riverqueue/river/internal"
 )
 
 // Driver provides a database driver for use with river.Client.
@@ -36,11 +34,6 @@ type Driver[TTx any] interface {
 	// where multiple drivers are supported and is subject to change.
 	GetDBPool() *pgxpool.Pool
 
-	// GetSentinel returns a sentinal value of a type that's internal to River.
-	// Its purpose is to prevent public code from implementing this interface
-	// because it's not meant to be used externally at this time.
-	GetSentinel() internal.Sentinel
-
 	// UnwrapTx turns a generically typed transaction into a pgx.Tx for use with
 	// internal infrastructure. This doesn't make sense in a world where
 	// multiple drivers are supported and is subject to change.

riverdriver/river_driver_interface_test.go

@@ -0,0 +1,10 @@
+package riverdriver
+
+import (
+	"github.com/jackc/pgx/v5"
+
+	"github.com/riverqueue/river/riverdriver/riverpgxv5"
+)
+
+// Verify interface compliance.
+var _ Driver[pgx.Tx] = &riverpgxv5.Driver{}

riverdriver/riverpgxv5/go.mod

@@ -0,0 +1,14 @@
+module github.com/riverqueue/river/riverdriver/riverpgxv5
+
+go 1.21.0
+
+require github.com/jackc/pgx/v5 v5.5.0
+
+require (
+	github.com/jackc/pgpassfile v1.0.0 // indirect
+	github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a // indirect
+	github.com/jackc/puddle/v2 v2.2.1 // indirect
+	golang.org/x/crypto v0.15.0 // indirect
+	golang.org/x/sync v0.5.0 // indirect
+	golang.org/x/text v0.14.0 // indirect
+)

riverdriver/riverpgxv5/go.sum

@@ -0,0 +1,28 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
+github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
+github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a h1:bbPeKD0xmW/Y25WS6cokEszi5g+S0QxI/d45PkRi7Nk=
+github.com/jackc/pgservicefile v0.0.0-20221227161230-091c0ba34f0a/go.mod h1:5TJZWKEWniPve33vlWYSoGYefn3gLQRzjfDlhSJ9ZKM=
+github.com/jackc/pgx/v5 v5.5.0 h1:NxstgwndsTRy7eq9/kqYc/BZh5w2hHJV86wjvO+1xPw=
+github.com/jackc/pgx/v5 v5.5.0/go.mod h1:Ig06C2Vu0t5qXC60W8sqIthScaEnFvojjj9dSljmHRA=
+github.com/jackc/puddle/v2 v2.2.1 h1:RhxXJtFG022u4ibrCSMSiu5aOq1i77R3OHKNJj77OAk=
+github.com/jackc/puddle/v2 v2.2.1/go.mod h1:vriiEXHvEE654aYKXXjOvZM39qJ0q+azkZFrfEOc3H4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
+github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
+golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
+golang.org/x/sync v0.5.0 h1:60k92dhOjHxJkrqnwsfl8KuaHbn/5dl0lUPUklKo3qE=
+golang.org/x/sync v0.5.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
+golang.org/x/text v0.14.0/go.mod h1:18ZOQIKpY8NJVqYksKHtTdi31H5itFRjB5/qKTNYzSU=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

riverdriver/riverpgxv5/river_pgx_v5_driver.go

@@ -8,9 +8,6 @@ package riverpgxv5
 import (
 	"github.com/jackc/pgx/v5"
 	"github.com/jackc/pgx/v5/pgxpool"
-
-	"github.com/riverqueue/river/internal"
-	"github.com/riverqueue/river/riverdriver"
 )
 
 // Driver is an implementation of riverdriver.Driver for Pgx v5.
@@ -25,10 +22,9 @@ type Driver struct {
 //
 // The pool must not be closed while the associated client is running (not until
 // graceful shutdown has completed).
-func New(dbPool *pgxpool.Pool) riverdriver.Driver[pgx.Tx] {
+func New(dbPool *pgxpool.Pool) *Driver {
 	return &Driver{dbPool: dbPool}
 }
 
-func (d *Driver) GetDBPool() *pgxpool.Pool       { return d.dbPool }
-func (d *Driver) GetSentinel() internal.Sentinel { return internal.Sentinel{} }
-func (d *Driver) UnwrapTx(tx pgx.Tx) pgx.Tx      { return tx }
+func (d *Driver) GetDBPool() *pgxpool.Pool  { return d.dbPool }
+func (d *Driver) UnwrapTx(tx pgx.Tx) pgx.Tx { return tx }