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| author | Jonathan Amsterdam <jba@google.com> | 2019-08-02 06:43:20 -0400 |
|---|---|---|
| committer | Jonathan Amsterdam <jba@google.com> | 2019-08-06 11:13:05 +0000 |
| commit | 546ea78efa159680dde0df42f1f2091ccafef4df (patch) | |
| tree | 6a6651d24b88ee567f02a26196feda32f99a396d /src/errors/wrap.go | |
| parent | a4c825156d0a3817377a2b7e5b30ab50e11440ab (diff) | |
| download | go-546ea78efa159680dde0df42f1f2091ccafef4df.tar.xz | |
errors: improve doc
Explain wrapping and how to use Is and As in the package doc.
Explain "chain" in Is and As.
Updates #33364.
Change-Id: Ic06362106dbd129e33dd47e63176ee5355492086
Reviewed-on: https://go-review.googlesource.com/c/go/+/188737
Reviewed-by: Rob Pike <r@golang.org>
Diffstat (limited to 'src/errors/wrap.go')
| -rw-r--r-- | src/errors/wrap.go | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/errors/wrap.go b/src/errors/wrap.go index 666d1ff207..240da37c29 100644 --- a/src/errors/wrap.go +++ b/src/errors/wrap.go @@ -23,6 +23,9 @@ func Unwrap(err error) error { // Is reports whether any error in err's chain matches target. // +// The chain consists of err itself followed by the sequence of errors obtained by +// repeatedly calling Unwrap. +// // An error is considered to match a target if it is equal to that target or if // it implements a method Is(error) bool such that Is(target) returns true. func Is(err, target error) bool { @@ -50,6 +53,9 @@ func Is(err, target error) bool { // As finds the first error in err's chain that matches target, and if so, sets // target to that error value and returns true. // +// The chain consists of err itself followed by the sequence of errors obtained by +// repeatedly calling Unwrap. +// // An error matches target if the error's concrete value is assignable to the value // pointed to by target, or if the error has a method As(interface{}) bool such that // As(target) returns true. In the latter case, the As method is responsible for |