Make every not exist error unwrappable to a fs.ErrNotExist (#20891)

A lot of our code is repeatedly testing if individual errors are
specific types of Not Exist errors. This is repetitative and unnecesary.
`Unwrap() error` provides a common way of labelling an error as a
NotExist error and we can/should use this.

This PR has chosen to use the common `io/fs` errors e.g.
`fs.ErrNotExist` for our errors. This is in some ways not completely
correct as these are not filesystem errors but it seems like a
reasonable thing to do and would allow us to simplify a lot of our code
to `errors.Is(err, fs.ErrNotExist)` instead of
`package.IsErr...NotExist(err)`

I am open to suggestions to use a different base error - perhaps
`models/db.ErrNotExist` if that would be felt to be better.


Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: delvh <dev.lh@web.de>

1 files changed, 11 insertions, 1 deletions

diff --git a/models/auth/oauth2.go b/models/auth/oauth2.go
index abcd9e1ca6..9fdce24253 100644
--- a/models/auth/oauth2.go
+++ b/models/auth/oauth2.go
@@ -486,7 +486,7 @@ type ErrOAuthClientIDInvalid struct {
 	ClientID string
 }
 
-// IsErrOauthClientIDInvalid checks if an error is a ErrReviewNotExist.
+// IsErrOauthClientIDInvalid checks if an error is a ErrOAuthClientIDInvalid.
 func IsErrOauthClientIDInvalid(err error) bool {
 	_, ok := err.(ErrOAuthClientIDInvalid)
 	return ok
@@ -497,6 +497,11 @@ func (err ErrOAuthClientIDInvalid) Error() string {
 	return fmt.Sprintf("Client ID invalid [Client ID: %s]", err.ClientID)
 }
 
+// Unwrap unwraps this as a ErrNotExist err
+func (err ErrOAuthClientIDInvalid) Unwrap() error {
+	return util.ErrNotExist
+}
+
 // ErrOAuthApplicationNotFound will be thrown if id cannot be found
 type ErrOAuthApplicationNotFound struct {
 	ID int64
@@ -513,6 +518,11 @@ func (err ErrOAuthApplicationNotFound) Error() string {
 	return fmt.Sprintf("OAuth application not found [ID: %d]", err.ID)
 }
 
+// Unwrap unwraps this as a ErrNotExist err
+func (err ErrOAuthApplicationNotFound) Unwrap() error {
+	return util.ErrNotExist
+}
+
 // GetActiveOAuth2ProviderSources returns all actived LoginOAuth2 sources
 func GetActiveOAuth2ProviderSources() ([]*Source, error) {
 	sources := make([]*Source, 0, 1)