fix: restore support and testing of Go 1.22.0

- relax go directive to 1.22.0 to match the N-1 and N support statement
  and permit run/build with go1.22.0 and newer
- update the test fixtures go.mod similarly to make them representative
- use the toolchain directive to _recommend_ the latest 1.23.x (Go
  treats this as advisory)
- fix the CI build so that oldstable and stable are actually being
  tested by telling setup-go to ignore the toolchain directive
- use go build tags to add a stub for types.Alias on go1.22 and
  (somewhat ironically!) use a simple type Alias to the builtin on
  go1.23 and newer

Fixes #312

Signed-off-by: Dominic Evans <dominic.evans@uk.ibm.com>

.github/workflows/go.yml

@@ -6,9 +6,15 @@ on:
     inputs:
       debug_enabled:
         type: boolean
-        description: 'Run the build with tmate debugging enabled (https://github.com/marketplace/actions/debugging-with-tmate)'
+        description: "Run the build with tmate debugging enabled (https://github.com/marketplace/actions/debugging-with-tmate)"
         required: false
         default: false
+env:
+  # GOOTOOLCHAIN=local tells Go to only use the installed Go version (from the
+  # build matrix) rather than immediately upgrading to whatever is specified by
+  # the `toolchain` directive in `go.mod`. This ensures that the build matrix
+  # versions (stable and oldstable) are actually being validated.
+  GOTOOLCHAIN: local
 jobs:
   build:
     name: Build and Test

fixtures/dup_packages/go.mod

@@ -1,3 +1,5 @@
 module github.com/maxbrunsfeld/counterfeiter/v6/fixtures/dup_packages
 
-go 1.22
+go 1.22.0
+
+toolchain go1.23.5

fixtures/hyphenated_package_same_name/go.mod

@@ -1 +1,5 @@
 module github.com/maxbrunsfeld/counterfeiter/v6/fixtures/hyphenated_package_same_name
+
+go 1.22.0
+
+toolchain go1.23.5

fixtures/type_aliases/go.mod

@@ -1,3 +1,5 @@
 module github.com/maxbrunsfeld/counterfeiter/v6/fixtures/type_aliases
 
-go 1.22
+go 1.22.0
+
+toolchain go1.23.5

generator/loader.go

@@ -13,6 +13,11 @@ import (
 	"golang.org/x/tools/imports"
 )
 
+type namedType interface {
+	Obj() *types.TypeName
+	TypeArgs() *types.TypeList
+}
+
 func (f *Fake) loadPackages(c Cacher, workingDir string) error {
 	log.Println("loading packages...")
 	p, ok := c.Load(f.TargetPackage)
@@ -169,7 +174,7 @@ func (f *Fake) addImportsFor(typ types.Type) {
 		f.addImportsFor(t.Elem())
 	case *types.Chan:
 		f.addImportsFor(t.Elem())
-	case *types.Alias:
+	case *typesAlias: // note: using stub or alias from types_alias_go1.22.go or types_alias_go1.23.go as appropriate
 		f.addImportsForNamedType(t)
 	case *types.Named:
 		f.addImportsForNamedType(t)
@@ -190,10 +195,7 @@ func (f *Fake) addImportsFor(typ types.Type) {
 	}
 }
 
-func (f *Fake) addImportsForNamedType(t interface {
-	Obj() *types.TypeName
-	TypeArgs() *types.TypeList
-}) {
+func (f *Fake) addImportsForNamedType(t namedType) {
 	if t.Obj() != nil && t.Obj().Pkg() != nil {
 		typeArgs := t.TypeArgs()
 		for i := 0; i < typeArgs.Len(); i++ {

generator/types_alias_go122.go

@@ -0,0 +1,27 @@
+//go:build !go1.23
+
+package generator
+
+import (
+	"go/types"
+)
+
+var _ namedType = &typesAlias{}
+
+type typesAlias struct{}
+
+func (a *typesAlias) Obj() *types.TypeName {
+	panic("counterfeiter itself must be run/built with go1.23 or newer in order to handle type aliasing")
+}
+
+func (a *typesAlias) String() string {
+	panic("counterfeiter itself must be run/built with go1.23 or newer in order to handle type aliasing")
+}
+
+func (a *typesAlias) TypeArgs() *types.TypeList {
+	panic("counterfeiter itself must be run/built with go1.23 or newer in order to handle type aliasing")
+}
+
+func (a *typesAlias) Underlying() types.Type {
+	panic("counterfeiter itself must be run/built with go1.23 or newer in order to handle type aliasing")
+}

generator/types_alias_go123.go

@@ -0,0 +1,11 @@
+//go:build go1.23
+
+package generator
+
+import (
+	"go/types"
+)
+
+var _ types.Type = &typesAlias{}
+
+type typesAlias = types.Alias

go.mod

@@ -1,5 +1,9 @@
 module github.com/maxbrunsfeld/counterfeiter/v6
 
+go 1.22.0
+
+toolchain go1.23.5
+
 require (
 	github.com/onsi/gomega v1.36.2
 	github.com/sclevine/spec v1.4.0
@@ -9,13 +13,10 @@ require (
 
 require (
 	github.com/google/go-cmp v0.6.0 // indirect
+	github.com/kr/pretty v0.3.1 // indirect
 	golang.org/x/mod v0.22.0 // indirect
 	golang.org/x/net v0.34.0 // indirect
 	golang.org/x/sync v0.10.0 // indirect
 	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
-
-go 1.23
-
-toolchain go1.23.1

go.sum

@@ -1,3 +1,4 @@
+github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/go-logr/logr v1.4.2 h1:6pFjapn8bFcIbiKo3XT4j/BhANplGihG6tvd+8rYgrY=
 github.com/go-logr/logr v1.4.2/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY=
 github.com/go-task/slim-sprig/v3 v3.0.0 h1:sUs3vkvUymDpBKi3qH1YSqBQk9+9D/8M2mN1vB6EwHI=
@@ -6,15 +7,20 @@ github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad h1:a6HEuzUHeKH6hwfN/ZoQgRgVIWFJljSWa/zetS2WTvg=
 github.com/google/pprof v0.0.0-20241210010833-40e02aabc2ad/go.mod h1:vavhavw2zAxS5dIdcRluK6cSGGPlZynqzFM8NdvU144=
-github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
 github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
+github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
-github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
+github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/onsi/ginkgo/v2 v2.22.1 h1:QW7tbJAUDyVDVOM5dFa7qaybo+CRfR7bemlQUN6Z8aM=
 github.com/onsi/ginkgo/v2 v2.22.1/go.mod h1:S6aTpoRsSq2cZOd+pssHAlKW/Q/jZt6cPrPlnj4a1xM=
 github.com/onsi/gomega v1.36.2 h1:koNYke6TVk6ZmnyHrCXba/T/MoLBXFjeC1PtvYgw0A8=
 github.com/onsi/gomega v1.36.2/go.mod h1:DdwyADRjrc825LhMEkD76cHR5+pUnjhUN8GlHlRPHzY=
+github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
+github.com/rogpeppe/go-internal v1.9.0 h1:73kH8U+JUqXU8lRuOHeVHaa/SZPifC7BkcraZVejAe8=
+github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/sclevine/spec v1.4.0 h1:z/Q9idDcay5m5irkZ28M7PtQM4aOISzOpj4bUPkDee8=
 github.com/sclevine/spec v1.4.0/go.mod h1:LvpgJaFyvQzRvc1kaDs0bulYwzC70PbiYjC4QnFHkOM=
 golang.org/x/mod v0.22.0 h1:D4nJWe9zXqHOmWqj4VMOJhvzj7bEZg4wEYa759z1pH4=