CL #163058 moves interpretation of platform-specific errors to the
syscall package. Package syscall errors implement an Is method which
os.IsPermission etc. consult. This results in an unintended semantic
change to the os package predicate functions: The following program
now prints 'true' where it used to print 'false':
package main
import "os"
type myError struct{ error }
func (e myError) Is(target error) bool { return target == os.ErrPermission }
func main() { println(os.IsPermission(myError{})) }
Change the os package error predicate functions to only examine syscall
errors, avoiding this semantic change.
This CL does retain one minor semantic change: On Plan9, os.IsPermission
used to return true for any error with text containing the string
"permission denied". It now only returns true for a syscall.ErrorString
containing that text.
Change-Id: I6b512b1de6ced46c2f1cc8d264fa2495ae7bf9f5
Reviewed-on: https://go-review.googlesource.com/c/go/+/188817
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
As proposed in Issue #29934, update errors produced by the os package to
work with errors.Is sentinel tests. For example,
errors.Is(err, os.ErrPermission) is equivalent to os.IsPermission(err)
with added unwrapping support.
Move the definition for os.ErrPermission and others into the syscall
package. Add an Is method to syscall.Errno and others. Add an Unwrap
method to os.PathError and others.
Updates #30322
Updates #29934
Change-Id: I95727d26c18a5354c720de316dff0bffc04dd926
Reviewed-on: https://go-review.googlesource.com/c/go/+/163058
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Add an Unwrap method to PathError so it works with the errors.Is/As
functions.
Change-Id: Ia6171c0418584f3cd53ee99d97c687941a9e3109
Reviewed-on: https://go-review.googlesource.com/c/go/+/168097
Reviewed-by: Damien Neil <dneil@google.com>
Damien Neil
Jonathan Amsterdam
Dan Caddigan
Brad Fitzpatrick
Russ Cox