Query policy (#411)

* entc/gen: drop xerrors package usage

* all: bump dependencies version

* entc/gen: adding query privacy policy support

examples/start/ent/car_query.go

@@ -327,7 +327,6 @@ func (cq *CarQuery) prepareQuery(ctx context.Context) error {
 		}
 		cq.sql = prev
 	}
-	// Privacy and query checks go here.
 	return nil
 }
 

examples/start/ent/ent.go

@@ -8,6 +8,7 @@ package ent
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"strings"
 
@@ -15,7 +16,6 @@ import (
 	"github.com/facebookincubator/ent/dialect"
 	"github.com/facebookincubator/ent/dialect/sql"
 	"github.com/facebookincubator/ent/dialect/sql/sqlgraph"
-	"golang.org/x/xerrors"
 )
 
 // ent aliases to avoid import conflict in user's code.
@@ -24,6 +24,7 @@ type (
 	Hook       = ent.Hook
 	Value      = ent.Value
 	Query      = ent.Query
+	Policy     = ent.Policy
 	Mutator    = ent.Mutator
 	Mutation   = ent.Mutation
 	MutateFunc = ent.MutateFunc
@@ -116,7 +117,7 @@ func IsNotFound(err error) bool {
 		return false
 	}
 	var e *NotFoundError
-	return xerrors.As(err, &e)
+	return errors.As(err, &e)
 }
 
 // MaskNotFound masks nor found error.
@@ -143,7 +144,7 @@ func IsNotSingular(err error) bool {
 		return false
 	}
 	var e *NotSingularError
-	return xerrors.As(err, &e)
+	return errors.As(err, &e)
 }
 
 // NotLoadedError returns when trying to get a node that was not loaded by the query.
@@ -162,7 +163,7 @@ func IsNotLoaded(err error) bool {
 		return false
 	}
 	var e *NotLoadedError
-	return xerrors.As(err, &e)
+	return errors.As(err, &e)
 }
 
 // ConstraintError returns when trying to create/update one or more entities and
@@ -189,7 +190,7 @@ func IsConstraintError(err error) bool {
 		return false
 	}
 	var e *ConstraintError
-	return xerrors.As(err, &e)
+	return errors.As(err, &e)
 }
 
 func isSQLConstraintError(err error) (*ConstraintError, bool) {

examples/start/ent/group_query.go

@@ -327,7 +327,6 @@ func (gq *GroupQuery) prepareQuery(ctx context.Context) error {
 		}
 		gq.sql = prev
 	}
-	// Privacy and query checks go here.
 	return nil
 }
 

examples/start/ent/user_query.go

@@ -358,7 +358,6 @@ func (uq *UserQuery) prepareQuery(ctx context.Context) error {
 		}
 		uq.sql = prev
 	}
-	// Privacy and query checks go here.
 	return nil
 }