testscript: add support for Go master aka 1.18

Fuzzing support brought a new parameter to MainStart,
as well as more methods on testDeps.
Use build tags to support those without breaking 1.16 nor 1.17.

While at it, bump CI to test the two latest Go versions,
and run 1.17's gofmt, as CI demands it.

Finally, make CI also test with Go's master version,
to ensure that we are compatible with it.
We pin a specific commit, since that keeps CI stable.

Fixes #144.

Co-authored-by: Roger Peppe <rogpeppe@gmail.com>

.github/workflows/test.yml

@@ -11,7 +11,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        go-version: [1.15.x, 1.16.x]
+        go-version: [1.16.x, 1.17.x]
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
@@ -34,3 +34,30 @@ jobs:
 
         test -z "$(gofmt -d .)" || (gofmt -d . && false)
         test -z "$(git status --porcelain)" || (git status; git diff && false)
+
+  test-gotip:
+    runs-on: ubuntu-latest
+    continue-on-error: true # master breaks sometimes
+    steps:
+    - name: Install Go
+      env:
+        GO_COMMIT: d0dd26a88c019d54f22463daae81e785f5867565 # 2021-09-23
+      run: |
+        cd $HOME
+        mkdir $HOME/gotip
+        cd $HOME/gotip
+
+        wget -O gotip.tar.gz https://go.googlesource.com/go/+archive/${GO_COMMIT}.tar.gz
+        tar -xf gotip.tar.gz
+        echo "devel go1.18-${GO_COMMIT}" >VERSION
+
+        cd src
+        ./make.bash
+        echo "GOROOT=$HOME/gotip" >>$GITHUB_ENV
+        echo "$HOME/gotip/bin" >>$GITHUB_PATH
+    - name: Checkout code
+      uses: actions/checkout@v2
+    - name: Test
+      run: |
+        go version
+        go test ./...

cache/default_unix_test.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !windows && !darwin && !plan9
 // +build !windows,!darwin,!plan9
 
 package cache

fmtsort/mapelem.go

@@ -1,3 +1,4 @@
+//go:build go1.12
 // +build go1.12
 
 package fmtsort

fmtsort/mapelem_1.11.go

@@ -1,3 +1,4 @@
+//go:build !go1.12
 // +build !go1.12
 
 package fmtsort

go.mod

@@ -1,6 +1,6 @@
 module github.com/rogpeppe/go-internal
 
-go 1.15
+go 1.16
 
 require (
 	github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e

imports/testdata/import1/x1.go

@@ -1,8 +1,5 @@
-// +build blahblh
-// +build linux
-// +build !linux
-// +build windows
-// +build darwin
+//go:build blahblh && linux && !linux && windows && darwin
+// +build blahblh,linux,!linux,windows,darwin
 
 package x
 

internal/os/execpath/lp_js.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build js && wasm
 // +build js,wasm
 
 package execpath

internal/os/execpath/lp_unix.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build aix || darwin || dragonfly || freebsd || linux || nacl || netbsd || openbsd || solaris
 // +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
 
 package execpath

internal/syscall/windows/registry/key.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build windows
 // +build windows
 
 // Package registry provides access to the Windows registry.

internal/syscall/windows/registry/syscall.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build windows
 // +build windows
 
 package registry

internal/syscall/windows/registry/value.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build windows
 // +build windows
 
 package registry

lockedfile/internal/filelock/filelock_fcntl.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build aix || solaris
 // +build aix solaris
 
 // This code implements the filelock API using POSIX 'fcntl' locks, which attach

lockedfile/internal/filelock/filelock_other.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !aix && !darwin && !dragonfly && !freebsd && !linux && !netbsd && !openbsd && !plan9 && !solaris && !windows
 // +build !aix,!darwin,!dragonfly,!freebsd,!linux,!netbsd,!openbsd,!plan9,!solaris,!windows
 
 package filelock

lockedfile/internal/filelock/filelock_plan9.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build plan9
 // +build plan9
 
 package filelock

lockedfile/internal/filelock/filelock_test.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !js && !nacl && !plan9
 // +build !js,!nacl,!plan9
 
 package filelock_test

lockedfile/internal/filelock/filelock_unix.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build darwin || dragonfly || freebsd || linux || netbsd || openbsd
 // +build darwin dragonfly freebsd linux netbsd openbsd
 
 package filelock

lockedfile/internal/filelock/filelock_windows.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build windows
 // +build windows
 
 package filelock

lockedfile/lockedfile_filelock.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !plan9
 // +build !plan9
 
 package lockedfile

lockedfile/lockedfile_plan9.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build plan9
 // +build plan9
 
 package lockedfile

lockedfile/lockedfile_test.go

@@ -3,6 +3,7 @@
 // license that can be found in the LICENSE file.
 
 // js and nacl do not support inter-process file locking.
+//go:build !js && !nacl
 // +build !js,!nacl
 
 package lockedfile_test

testenv/testenv_cgo.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build cgo
 // +build cgo
 
 package testenv

testenv/testenv_notwin.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !windows
 // +build !windows
 
 package testenv

testscript/envvarname.go

@@ -1,3 +1,4 @@
+//go:build !windows
 // +build !windows
 
 package testscript

testscript/exe.go

@@ -15,7 +15,6 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
-	"testing"
 )
 
 // TestingM is implemented by *testing.M. It's defined as an interface
@@ -228,7 +227,7 @@ func runCoverSubcommand(cprof string, mainf func() int) (exitCode int) {
 
 		// Run MainStart (recursively, but it we should be ok) with no tests
 		// so that it writes the coverage profile.
-		m := testing.MainStart(nopTestDeps{}, nil, nil, nil)
+		m := mainStart()
 		if code := m.Run(); code != 0 && exitCode == 0 {
 			exitCode = code
 		}

testscript/exe_go118.go

@@ -0,0 +1,51 @@
+//go:build go1.18
+// +build go1.18
+
+package testscript
+
+import (
+	"reflect"
+	"testing"
+	"time"
+)
+
+func mainStart() *testing.M {
+	// Note: testing.MainStart acquired an extra argument in Go 1.18.
+	return testing.MainStart(nopTestDeps{}, nil, nil, nil, nil)
+}
+
+// Note: corpusEntry is an anonymous struct type used by some method stubs.
+type corpusEntry = struct {
+	Parent     string
+	Name       string
+	Data       []byte
+	Values     []interface{}
+	Generation int
+	IsSeed     bool
+}
+
+// Note: CoordinateFuzzing was added in Go 1.18.
+func (nopTestDeps) CoordinateFuzzing(time.Duration, int64, time.Duration, int64, int, []corpusEntry, []reflect.Type, string, string) error {
+	return nil
+}
+
+// Note: RunFuzzWorker was added in Go 1.18.
+func (nopTestDeps) RunFuzzWorker(func(corpusEntry) error) error {
+	return nil
+}
+
+// Note: ReadCorpus was added in Go 1.18.
+func (nopTestDeps) ReadCorpus(string, []reflect.Type) ([]corpusEntry, error) {
+	return nil, nil
+}
+
+// Note: CheckCorpus was added in Go 1.18.
+func (nopTestDeps) CheckCorpus([]interface{}, []reflect.Type) error {
+	return nil
+}
+
+// Note: ResetCoverage was added in Go 1.18.
+func (nopTestDeps) ResetCoverage() {}
+
+// Note: SnapshotCoverage was added in Go 1.18.
+func (nopTestDeps) SnapshotCoverage() {}

testscript/exe_pre_go1.18.go

@@ -0,0 +1,12 @@
+//go:build !go1.18
+// +build !go1.18
+
+package testscript
+
+import (
+	"testing"
+)
+
+func mainStart() *testing.M {
+	return testing.MainStart(nopTestDeps{}, nil, nil, nil)
+}