Satisfy errors.Is even if formatting is incorrect

.gitignore

@@ -21,3 +21,6 @@ _testmain.go
 
 *.exe
 *.test
+
+# IDE files
+/.idea/

errortypes.go

@@ -116,7 +116,7 @@ func WithType(err error, errType ConstError) error {
 // interface.
 func Timeoutf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Timeout, format, args...),
+		WithType(makeWrappedConstError(Timeout, format, args...), Timeout),
 		1,
 	)
 }
@@ -140,7 +140,7 @@ func IsTimeout(err error) bool {
 // Locationer interface.
 func NotFoundf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(NotFound, format, args...),
+		WithType(makeWrappedConstError(NotFound, format, args...), NotFound),
 		1,
 	)
 }
@@ -164,7 +164,7 @@ func IsNotFound(err error) bool {
 // Locationer interface.
 func UserNotFoundf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(UserNotFound, format, args...),
+		WithType(makeWrappedConstError(UserNotFound, format, args...), UserNotFound),
 		1,
 	)
 }
@@ -188,7 +188,7 @@ func IsUserNotFound(err error) bool {
 // the Locationer interface.
 func Unauthorizedf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Hide(Unauthorized), format, args...),
+		WithType(makeWrappedConstError(Hide(Unauthorized), format, args...), Unauthorized),
 		1,
 	)
 }
@@ -212,7 +212,7 @@ func IsUnauthorized(err error) bool {
 // the Locationer interface.
 func NotImplementedf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(NotImplemented, format, args...),
+		WithType(makeWrappedConstError(NotImplemented, format, args...), NotImplemented),
 		1,
 	)
 }
@@ -236,7 +236,7 @@ func IsNotImplemented(err error) bool {
 // the Locationer interface.
 func AlreadyExistsf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(AlreadyExists, format, args...),
+		WithType(makeWrappedConstError(AlreadyExists, format, args...), AlreadyExists),
 		1,
 	)
 }
@@ -260,7 +260,7 @@ func IsAlreadyExists(err error) bool {
 // Locationer interface.
 func NotSupportedf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(NotSupported, format, args...),
+		WithType(makeWrappedConstError(NotSupported, format, args...), NotSupported),
 		1,
 	)
 }
@@ -284,7 +284,7 @@ func IsNotSupported(err error) bool {
 // Locationer interface.
 func NotValidf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(NotValid, format, args...),
+		WithType(makeWrappedConstError(NotValid, format, args...), NotValid),
 		1,
 	)
 }
@@ -308,7 +308,7 @@ func IsNotValid(err error) bool {
 // the Locationer interface.
 func NotProvisionedf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(NotProvisioned, format, args...),
+		WithType(makeWrappedConstError(NotProvisioned, format, args...), NotProvisioned),
 		1,
 	)
 }
@@ -332,7 +332,7 @@ func IsNotProvisioned(err error) bool {
 // Locationer interface.
 func NotAssignedf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(NotAssigned, format, args...),
+		WithType(makeWrappedConstError(NotAssigned, format, args...), NotAssigned),
 		1,
 	)
 }
@@ -356,7 +356,7 @@ func IsNotAssigned(err error) bool {
 // Locationer interface.
 func BadRequestf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Hide(BadRequest), format, args...),
+		WithType(makeWrappedConstError(Hide(BadRequest), format, args...), BadRequest),
 		1,
 	)
 }
@@ -380,7 +380,7 @@ func IsBadRequest(err error) bool {
 // and the Locationer interface.
 func MethodNotAllowedf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Hide(MethodNotAllowed), format, args...),
+		WithType(makeWrappedConstError(Hide(MethodNotAllowed), format, args...), MethodNotAllowed),
 		1,
 	)
 }
@@ -404,7 +404,7 @@ func IsMethodNotAllowed(err error) bool {
 // Locationer interface.
 func Forbiddenf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Hide(Forbidden), format, args...),
+		WithType(makeWrappedConstError(Hide(Forbidden), format, args...), Forbidden),
 		1,
 	)
 }
@@ -428,7 +428,7 @@ func IsForbidden(err error) bool {
 // Is(err, QuotaLimitExceeded) and the Locationer interface.
 func QuotaLimitExceededf(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Hide(QuotaLimitExceeded), format, args...),
+		WithType(makeWrappedConstError(Hide(QuotaLimitExceeded), format, args...), QuotaLimitExceeded),
 		1,
 	)
 }
@@ -452,7 +452,7 @@ func IsQuotaLimitExceeded(err error) bool {
 // and the Locationer interface.
 func NotYetAvailablef(format string, args ...interface{}) error {
 	return newLocationError(
-		makeWrappedConstError(Hide(NotYetAvailable), format, args...),
+		WithType(makeWrappedConstError(Hide(NotYetAvailable), format, args...), NotYetAvailable),
 		1,
 	)
 }

errortypes_test.go

@@ -193,3 +193,29 @@ func (*errorTypeSuite) TestWithType(c *gc.C) {
 	c.Assert(err.Error(), gc.Equals, "yes")
 	c.Assert(errors.Is(err, myErr2), gc.Equals, false)
 }
+
+func (*errorTypeSuite) TestBadFormatNotEnoughArgs(c *gc.C) {
+	errorTests := make([]errorTest, 0, len(allErrors))
+	for _, errInfo := range allErrors {
+		errorTests = append(errorTests, errorTest{
+			errInfo.argsConstructor("missing arg %v"),
+			".*",
+			errInfo,
+		})
+	}
+
+	runErrorTests(c, errorTests, true)
+}
+
+func (*errorTypeSuite) TestBadFormatTooManyArgs(c *gc.C) {
+	errorTests := make([]errorTest, 0, len(allErrors))
+	for _, errInfo := range allErrors {
+		errorTests = append(errorTests, errorTest{
+			errInfo.argsConstructor("extra arg %v", "foo", "bar"),
+			".*",
+			errInfo,
+		})
+	}
+
+	runErrorTests(c, errorTests, true)
+}