gop/env.Installed(); gop/ast.File.Pos()

ast/ast.go

@@ -1123,7 +1123,7 @@ type FileType = int16
 // are "free-floating" (see also issues #18593, #20744).
 type File struct {
 	Doc     *CommentGroup // associated documentation; or nil
-	Package token.Pos     // position of "package" keyword
+	Package token.Pos     // position of "package" keyword; or NoPos
 	Name    *Ident        // package name
 	Decls   []Decl        // top-level declarations; or nil
 
@@ -1145,7 +1145,12 @@ func (f *File) NoEntrypoint() bool {
 }
 
 // Pos returns position of first character belonging to the node.
-func (f *File) Pos() token.Pos { return f.Package }
+func (f *File) Pos() token.Pos {
+	if f.Package != token.NoPos {
+		return f.Package
+	}
+	return f.Name.NamePos
+}
 
 // End returns position of first character immediately after the node.
 func (f *File) End() token.Pos {

env/build.go

@@ -22,6 +22,7 @@ var (
 	buildDate string
 )
 
+// BuildDate returns build date of the `gop` command.
 func BuildDate() string {
 	return buildDate
 }

env/gop_nonwindows.go

@@ -0,0 +1,24 @@
+//go:build !windows
+// +build !windows
+
+/*
+ * Copyright (c) 2021 The GoPlus Authors (goplus.org). All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package env
+
+func isGopCmd(fname string) bool {
+	return fname == "gop"
+}

env/path.go

@@ -28,6 +28,8 @@ var (
 	defaultGopRoot string
 )
 
+// GOPROOT returns the root of the Go+ tree. It uses the GOPROOT environment variable,
+// if set at process start, or else the root used during the Go+ build.
 func GOPROOT() string {
 	gopRoot, err := findGopRoot()
 	if err != nil {

env/path_test.go

@@ -17,7 +17,6 @@
 package env
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"testing"
@@ -39,12 +38,13 @@ func findGoModFile(dir string) (modfile string, noCacheFile bool, err error) {
 
 // Common testing directory structure:
 // testing_root/
-//   src/
-//	   subdir/
-//   valid_goproot/
-//	   go.mod
-//	   go.sum
-//     cmd/gop/
+//
+//	  src/
+//		   subdir/
+//	  valid_goproot/
+//		   go.mod
+//		   go.sum
+//	    cmd/gop/
 func makeTestDir(t *testing.T) (root string, src string, gopRoot string) {
 	root, _ = filepath.EvalSymlinks(t.TempDir())
 	src = filepath.Join(root, "src")
@@ -57,12 +57,12 @@ func makeTestDir(t *testing.T) (root string, src string, gopRoot string) {
 func makeValidGopRoot(root string) {
 	os.Mkdir(root, 0755)
 	os.MkdirAll(filepath.Join(root, "cmd/gop"), 0755)
-	ioutil.WriteFile(filepath.Join(root, "go.mod"), []byte(""), 0644)
-	ioutil.WriteFile(filepath.Join(root, "go.sum"), []byte(""), 0644)
+	os.WriteFile(filepath.Join(root, "go.mod"), []byte(""), 0644)
+	os.WriteFile(filepath.Join(root, "go.sum"), []byte(""), 0644)
 }
 
 func writeDummyFile(path string) {
-	ioutil.WriteFile(path, []byte(""), 0644)
+	os.WriteFile(path, []byte(""), 0644)
 }
 
 func cleanup() {

env/sys_windows.go

@@ -19,3 +19,7 @@ package env
 const (
 	envHOME = "USERPROFILE"
 )
+
+func isGopCmd(fname string) bool {
+	return fname == "gop.exe" || fname == "gop"
+}

env/version.go

@@ -17,6 +17,10 @@
 package env
 
 import (
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
 	"strings"
 )
 
@@ -31,9 +35,42 @@ var (
 )
 
 func init() {
-	if buildVersion != "" && !strings.HasPrefix(buildVersion, "v"+MainVersion+".") {
-		panic("Invalid buildVersion: " + buildVersion)
+	initEnv()
+}
+
+func initEnv() {
+	if buildVersion == "" {
+		initEnvByGop()
+		return
 	}
+	if !strings.HasPrefix(buildVersion, "v"+MainVersion+".") {
+		panic("gop/env: [FATAL] Invalid buildVersion: " + buildVersion)
+	}
+}
+
+func initEnvByGop() {
+	if fname := filepath.Base(os.Args[0]); !isGopCmd(fname) {
+		if ret, err := gopEnv(); err == nil {
+			parts := strings.SplitN(strings.TrimRight(ret, "\n"), "\n", 3)
+			if len(parts) == 3 {
+				buildVersion, buildDate, defaultGopRoot = parts[0], parts[1], parts[2]
+			}
+		}
+	}
+}
+
+var gopEnv = func() (string, error) {
+	var b bytes.Buffer
+	cmd := exec.Command("gop", "env", "GOPVERSION", "BUILDDATE", "GOPROOT")
+	cmd.Stdout = &b
+	err := cmd.Run()
+	return b.String(), err
+}
+
+// Installed checks is `gop` installed or not.
+// If returns false, it means `gop` is not installed or not in PATH.
+func Installed() bool {
+	return buildVersion != ""
 }
 
 // Version returns the GoPlus tree's version string.

env/version_test.go

@@ -16,21 +16,53 @@
 
 package env
 
-import "testing"
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
 
-func TestVersion(t *testing.T) {
-	if Version() != "v"+MainVersion+".x" {
-		t.Fatal("TestVersion failed:", Version())
+func TestPanic(t *testing.T) {
+	t.Run("initEnvPanic", func(t *testing.T) {
+		defer func() {
+			if e := recover(); e == nil {
+				t.Fatal("initEnvPanic: no panic?")
+			}
+		}()
+		buildVersion = "v1.2"
+		initEnv()
+	})
+	t.Run("GOPROOT panic", func(t *testing.T) {
+		defer func() {
+			if e := recover(); e == nil {
+				t.Fatal("GOPROOT: no panic?")
+			}
+		}()
+		defaultGopRoot = ""
+		os.Setenv(envGOPROOT, "")
+		GOPROOT()
+	})
+}
+
+func TestEnv(t *testing.T) {
+	gopEnv = func() (string, error) {
+		wd, _ := os.Getwd()
+		root := filepath.Dir(wd)
+		return "v1.0.0-beta1\n2023-10-18_17-45-50\n" + root + "\n", nil
+	}
+	buildVersion = ""
+	initEnv()
+	if !Installed() {
+		t.Fatal("not Installed")
 	}
-	buildVersion = "v1.0.0-beta1"
-	if Version() != buildVersion {
+	if Version() != "v1.0.0-beta1" {
 		t.Fatal("TestVersion failed:", Version())
 	}
 	buildVersion = ""
-}
-
-func TestBuild(t *testing.T) {
-	if BuildDate() != "" {
+	if Version() != "v"+MainVersion+".x" {
+		t.Fatal("TestVersion failed:", Version())
+	}
+	if BuildDate() != "2023-10-18_17-45-50" {
 		t.Fatal("BuildInfo failed:", BuildDate())
 	}
 }

parser/parser.go

@@ -3709,7 +3709,7 @@ func (p *parser) parseFile() *ast.File {
 	} else {
 		noPkgDecl = true
 		pos = token.NoPos
-		ident = ast.NewIdent("main")
+		ident = &ast.Ident{NamePos: p.file.Pos(0), Name: "main"}
 	}
 
 	p.openScope()