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-rw-r--r--vendor/golang.org/x/xerrors/doc.go23
-rw-r--r--vendor/golang.org/x/xerrors/fmt.go138
2 files changed, 118 insertions, 43 deletions
diff --git a/vendor/golang.org/x/xerrors/doc.go b/vendor/golang.org/x/xerrors/doc.go
index 1ad48f50b..eef99d9d5 100644
--- a/vendor/golang.org/x/xerrors/doc.go
+++ b/vendor/golang.org/x/xerrors/doc.go
@@ -4,22 +4,19 @@
// Package xerrors implements functions to manipulate errors.
//
-// This package supports transitioning to the Go 2 proposal for error values:
+// This package is based on the Go 2 proposal for error values:
// https://golang.org/design/29934-error-values
//
-// Most of the functions and types in this package will be incorporated into the
-// standard library's errors package in Go 1.13; the behavior of this package's
-// Errorf function will be incorporated into the standard library's fmt.Errorf.
-// Use this package to get equivalent behavior in all supported Go versions. For
-// example, create errors using
+// These functions were incorporated into the standard library's errors package
+// in Go 1.13:
+// - Is
+// - As
+// - Unwrap
//
-// xerrors.New("write failed")
+// Also, Errorf's %w verb was incorporated into fmt.Errorf.
//
-// or
+// Use this package to get equivalent behavior in all supported Go versions.
//
-// xerrors.Errorf("while reading: %v", err)
-//
-// If you want your error type to participate in the new formatting
-// implementation for %v and %+v, provide it with a Format method that calls
-// xerrors.FormatError, as shown in the example for FormatError.
+// No other features of this package were included in Go 1.13, and at present
+// there are no plans to include any of them.
package xerrors // import "golang.org/x/xerrors"
diff --git a/vendor/golang.org/x/xerrors/fmt.go b/vendor/golang.org/x/xerrors/fmt.go
index 74c1c93ec..829862ddf 100644
--- a/vendor/golang.org/x/xerrors/fmt.go
+++ b/vendor/golang.org/x/xerrors/fmt.go
@@ -7,10 +7,14 @@ package xerrors
import (
"fmt"
"strings"
+ "unicode"
+ "unicode/utf8"
"golang.org/x/xerrors/internal"
)
+const percentBangString = "%!"
+
// Errorf formats according to a format specifier and returns the string as a
// value that satisfies error.
//
@@ -18,29 +22,71 @@ import (
// formatted with additional detail enabled. If the last argument is an error
// the returned error's Format method will return it if the format string ends
// with ": %s", ": %v", or ": %w". If the last argument is an error and the
-// format string ends with ": %w", the returned error implements Wrapper
-// with an Unwrap method returning it.
+// format string ends with ": %w", the returned error implements an Unwrap
+// method returning it.
+//
+// If the format specifier includes a %w verb with an error operand in a
+// position other than at the end, the returned error will still implement an
+// Unwrap method returning the operand, but the error's Format method will not
+// return the wrapped error.
+//
+// It is invalid to include more than one %w verb or to supply it with an
+// operand that does not implement the error interface. The %w verb is otherwise
+// a synonym for %v.
func Errorf(format string, a ...interface{}) error {
- err, wrap := lastError(format, a)
format = formatPlusW(format)
- if err == nil {
- return &noWrapError{fmt.Sprintf(format, a...), nil, Caller(1)}
+ // Support a ": %[wsv]" suffix, which works well with xerrors.Formatter.
+ wrap := strings.HasSuffix(format, ": %w")
+ idx, format2, ok := parsePercentW(format)
+ percentWElsewhere := !wrap && idx >= 0
+ if !percentWElsewhere && (wrap || strings.HasSuffix(format, ": %s") || strings.HasSuffix(format, ": %v")) {
+ err := errorAt(a, len(a)-1)
+ if err == nil {
+ return &noWrapError{fmt.Sprintf(format, a...), nil, Caller(1)}
+ }
+ // TODO: this is not entirely correct. The error value could be
+ // printed elsewhere in format if it mixes numbered with unnumbered
+ // substitutions. With relatively small changes to doPrintf we can
+ // have it optionally ignore extra arguments and pass the argument
+ // list in its entirety.
+ msg := fmt.Sprintf(format[:len(format)-len(": %s")], a[:len(a)-1]...)
+ frame := Frame{}
+ if internal.EnableTrace {
+ frame = Caller(1)
+ }
+ if wrap {
+ return &wrapError{msg, err, frame}
+ }
+ return &noWrapError{msg, err, frame}
+ }
+ // Support %w anywhere.
+ // TODO: don't repeat the wrapped error's message when %w occurs in the middle.
+ msg := fmt.Sprintf(format2, a...)
+ if idx < 0 {
+ return &noWrapError{msg, nil, Caller(1)}
+ }
+ err := errorAt(a, idx)
+ if !ok || err == nil {
+ // Too many %ws or argument of %w is not an error. Approximate the Go
+ // 1.13 fmt.Errorf message.
+ return &noWrapError{fmt.Sprintf("%sw(%s)", percentBangString, msg), nil, Caller(1)}
}
-
- // TODO: this is not entirely correct. The error value could be
- // printed elsewhere in format if it mixes numbered with unnumbered
- // substitutions. With relatively small changes to doPrintf we can
- // have it optionally ignore extra arguments and pass the argument
- // list in its entirety.
- msg := fmt.Sprintf(format[:len(format)-len(": %s")], a[:len(a)-1]...)
frame := Frame{}
if internal.EnableTrace {
frame = Caller(1)
}
- if wrap {
- return &wrapError{msg, err, frame}
+ return &wrapError{msg, err, frame}
+}
+
+func errorAt(args []interface{}, i int) error {
+ if i < 0 || i >= len(args) {
+ return nil
}
- return &noWrapError{msg, err, frame}
+ err, ok := args[i].(error)
+ if !ok {
+ return nil
+ }
+ return err
}
// formatPlusW is used to avoid the vet check that will barf at %w.
@@ -48,24 +94,56 @@ func formatPlusW(s string) string {
return s
}
-func lastError(format string, a []interface{}) (err error, wrap bool) {
- wrap = strings.HasSuffix(format, ": %w")
- if !wrap &&
- !strings.HasSuffix(format, ": %s") &&
- !strings.HasSuffix(format, ": %v") {
- return nil, false
- }
-
- if len(a) == 0 {
- return nil, false
+// Return the index of the only %w in format, or -1 if none.
+// Also return a rewritten format string with %w replaced by %v, and
+// false if there is more than one %w.
+// TODO: handle "%[N]w".
+func parsePercentW(format string) (idx int, newFormat string, ok bool) {
+ // Loosely copied from golang.org/x/tools/go/analysis/passes/printf/printf.go.
+ idx = -1
+ ok = true
+ n := 0
+ sz := 0
+ var isW bool
+ for i := 0; i < len(format); i += sz {
+ if format[i] != '%' {
+ sz = 1
+ continue
+ }
+ // "%%" is not a format directive.
+ if i+1 < len(format) && format[i+1] == '%' {
+ sz = 2
+ continue
+ }
+ sz, isW = parsePrintfVerb(format[i:])
+ if isW {
+ if idx >= 0 {
+ ok = false
+ } else {
+ idx = n
+ }
+ // "Replace" the last character, the 'w', with a 'v'.
+ p := i + sz - 1
+ format = format[:p] + "v" + format[p+1:]
+ }
+ n++
}
+ return idx, format, ok
+}
- err, ok := a[len(a)-1].(error)
- if !ok {
- return nil, false
+// Parse the printf verb starting with a % at s[0].
+// Return how many bytes it occupies and whether the verb is 'w'.
+func parsePrintfVerb(s string) (int, bool) {
+ // Assume only that the directive is a sequence of non-letters followed by a single letter.
+ sz := 0
+ var r rune
+ for i := 1; i < len(s); i += sz {
+ r, sz = utf8.DecodeRuneInString(s[i:])
+ if unicode.IsLetter(r) {
+ return i + sz, r == 'w'
+ }
}
-
- return err, wrap
+ return len(s), false
}
type noWrapError struct {