Adding upstream version 0.0~git20250501.cd50c6a.

Signed-off-by: Daniel Baumann <daniel@debian.org>

redirects.go

@@ -0,0 +1,98 @@
+package errors
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func SeeOther(u string) *redirect {
+	return &redirect{s: http.StatusSeeOther, u: u}
+}
+func NewSeeOther(e error, u string) *redirect {
+	return &redirect{c: e, s: http.StatusSeeOther, u: u}
+}
+func Found(u string) *redirect {
+	return &redirect{s: http.StatusFound, u: u}
+}
+func NewFound(e error, u string) *redirect {
+	return &redirect{c: e, s: http.StatusFound, u: u}
+}
+func MovedPermanently(u string) *redirect {
+	return &redirect{s: http.StatusMovedPermanently, u: u}
+}
+func NewMovedPermanently(e error, u string) *redirect {
+	return &redirect{c: e, s: http.StatusMovedPermanently, u: u}
+}
+func NotModified(u string) *redirect {
+	return &redirect{s: http.StatusNotModified, u: u}
+}
+func NewNotModified(e error, u string) *redirect {
+	return &redirect{c: e, s: http.StatusNotModified, u: u}
+}
+func TemporaryRedirect(u string) *redirect {
+	return &redirect{s: http.StatusTemporaryRedirect, u: u}
+}
+func NewTemporaryRedirect(e error, u string) *redirect {
+	return &redirect{c: e, s: http.StatusTemporaryRedirect, u: u}
+}
+func PermanentRedirect(u string) *redirect {
+	return &redirect{s: http.StatusPermanentRedirect, u: u}
+}
+func NewPermanentRedirect(e error, u string) *redirect {
+	return &redirect{c: e, s: http.StatusPermanentRedirect, u: u}
+}
+
+type redirect struct {
+	c error
+	u string
+	s int
+}
+
+func (r redirect) Error() string {
+	if r.c == nil {
+		return fmt.Sprintf("Redirect %d to %s", r.s, r.u)
+	}
+	return fmt.Sprintf("Redirect %d to %s: %s", r.s, r.u, r.c)
+}
+
+// As is used by the errors.As() function to coerce the method's parameter to the one of the receiver
+//
+//	if the underlying logic of the receiver's type can understand it.
+//
+// In this case we're converting a forbidden to its underlying type Err.
+func (r *redirect) As(err interface{}) bool {
+	switch x := err.(type) {
+	case **redirect:
+		*x = r
+	case *redirect:
+		*x = *r
+	default:
+		return false
+	}
+	return true
+}
+
+func (r redirect) Is(e error) bool {
+	rr := redirect{}
+	return As(e, &rr) && r.s == rr.s
+}
+
+func IsRedirect(e error) bool {
+	_, okp := e.(*redirect)
+	_, oks := e.(redirect)
+	return okp || oks || As(e, &redirect{})
+}
+
+func IsNotModified(e error) bool {
+	ep, okp := e.(*redirect)
+	es, oks := e.(redirect)
+
+	ae := redirect{}
+	return (okp && ep.s == http.StatusNotModified) ||
+		(oks && es.s == http.StatusNotModified) ||
+		(As(e, &ae) && ae.s == http.StatusNotModified)
+}
+
+func (r redirect) Unwrap() error {
+	return r.Unwrap()
+}