Merge branch 'master' into RaduBerinde-patch-1

.travis.yml

@@ -2,7 +2,7 @@ language: go
 
 go:
 - 1.x
-- 1.8.x
+- 1.13.x
 
 script:
   - go test -p 1       -v ./...

crdb/README.md

@@ -6,7 +6,8 @@ retries (as required by CockroachDB).
 
 Note that unfortunately there is no generic way of extracting a pg error code;
 the library has to recognize driver-dependent error types. We currently support
-`github.com/lib/pq` and `github.com/jackc/pgx`.
+`github.com/lib/pq` and `github.com/jackc/pgconn` (which is used by
+`github.com/jackc/pgx/v4`; previous pgx versions are not supported).
 
 Note for developers: if you make any changes here (especially if they modify public
 APIs), please verify that the code in https://github.com/cockroachdb/examples-go 

crdb/error.go

@@ -11,19 +11,47 @@ type ErrorCauser interface {
 	Cause() error
 }
 
+// UnwrappableError describes errors compatible with errors.Unwrap.
+type UnwrappableError interface {
+	// Unwrap returns the proximate cause of this error.
+	Unwrap() error
+}
+
+// Unwrap is equivalent to errors.Unwrap. It's implemented here to maintain
+// compatibility with Go versions before 1.13 (when the errors package was
+// introduced).
+// It returns the result of calling the Unwrap method on err, if err's type
+// implements UnwrappableError.
+// Otherwise, Unwrap returns nil.
+func Unwrap(err error) error {
+	u, ok := err.(UnwrappableError)
+	if !ok {
+		return nil
+	}
+	return u.Unwrap()
+}
+
 // errorCause returns the original cause of the error, if possible. An error has
-// a proximate cause if it implements ErrorCauser; the original cause is the
-// first error in the cause chain that does not implement ErrorCauser.
-//
-// errorCause is intentionally equivalent to pkg/errors.Cause.
+// a proximate cause if it's type is compatible with Go's errors.Unwrap() (and
+// also, for legacy reasons, if it implements ErrorCauser); the original cause
+// is the bottom of the causal chain.
 func errorCause(err error) error {
+	// First handle errors implementing ErrorCauser.
 	for err != nil {
 		cause, ok := err.(ErrorCauser)
 		if !ok {
 			break
 		}
 		err = cause.Cause()
 	}
+	// Then handle go1.13+ error wrapping.
+	for {
+		cause := Unwrap(err)
+		if cause == nil {
+			break
+		}
+		err = cause
+	}
 	return err
 }
 

crdb/tx.go

@@ -20,7 +20,7 @@ import (
 	"context"
 	"database/sql"
 
-	"github.com/jackc/pgx"
+	"github.com/jackc/pgconn"
 	"github.com/lib/pq"
 )
 
@@ -143,7 +143,7 @@ func errCode(err error) string {
 	case *pq.Error:
 		return string(t.Code)
 
-	case pgx.PgError:
+	case *pgconn.PgError:
 		return t.Code
 
 	default:

crdb/tx_test.go

@@ -95,8 +95,16 @@ INSERT INTO d.t (acct, balance) VALUES (1, 100), (2, 100);
 	runTxn := func(wg *sync.WaitGroup, iter *int) <-chan error {
 		errCh := make(chan error, 1)
 		go func() {
+
 			*iter = 0
-			errCh <- executeTxFn(context.Background(), db, nil, func(tx *sql.Tx) error {
+			errCh <- executeTxFn(context.Background(), db, nil, func(tx *sql.Tx) (retErr error) {
+				defer func() {
+					if retErr == nil {
+						return
+					}
+					// Wrap the error so that we test the library's unwrapping.
+					retErr = testError{cause: retErr}
+				}()
 				*iter++
 				bal1, bal2, err := getBalances(tx)
 				if err != nil {
@@ -150,3 +158,15 @@ UPDATE d.t SET balance=balance-100 WHERE acct=2;
 			"got acct1=%d, acct2=%d: %s", bal1, bal2, err)
 	}
 }
+
+type testError struct {
+	cause error
+}
+
+func (t testError) Error() string {
+	return "test error"
+}
+
+func (t testError) Unwrap() error {
+	return t.cause
+}