cmd/generate-fastjson: use x/tools/go/packages (#1)

Use golang.org/x/tools/go/packages for parsing
Go packages, which works with Go modules.

.travis.yml

@@ -5,5 +5,8 @@ go:
   - stable
   - "1.8.x"
 
+install:
+  - go get
+
 script:
-  - go test -v ./...
+  - go test -v

cmd/generate-fastjson/main.go

@@ -19,19 +19,17 @@ import (
 	"flag"
 	"fmt"
 	"go/ast"
-	"go/build"
 	"go/format"
-	"go/importer"
-	"go/parser"
 	"go/token"
 	"go/types"
 	"io"
 	"log"
 	"os"
-	"path/filepath"
 	"reflect"
 	"sort"
 	"strings"
+
+	"golang.org/x/tools/go/packages"
 )
 
 const (
@@ -73,37 +71,18 @@ func main() {
 		}
 	}
 
-	cwd, err := os.Getwd()
-	if err != nil {
-		log.Fatal(err)
+	cfg := &packages.Config{
+		Mode: packages.NeedTypes | packages.NeedSyntax | packages.NeedTypesInfo,
 	}
-	buildPkg, err := build.Default.Import(flag.Arg(0), cwd, build.ImportComment)
+	pkgs, err := packages.Load(cfg, flag.Arg(0))
 	if err != nil {
-		log.Fatal(err)
-	}
-
-	fset := token.NewFileSet()
-	files := make([]*ast.File, len(buildPkg.GoFiles))
-	for i, goFile := range buildPkg.GoFiles {
-		filename := filepath.Join(buildPkg.Dir, goFile)
-		f, err := parser.ParseFile(fset, filename, nil, parser.ParseComments|parser.DeclarationErrors)
-		if err != nil {
-			log.Fatal(err)
-		}
-		files[i] = f
-	}
-
-	cfg := types.Config{
-		IgnoreFuncBodies: true,
-		Importer:         importer.Default(),
-	}
-	info := types.Info{
-		Defs: make(map[*ast.Ident]types.Object),
+		fmt.Fprintf(os.Stderr, "load: %v\n", err)
+		os.Exit(1)
 	}
-	pkg, err := cfg.Check(buildPkg.ImportPath, fset, files, &info)
-	if err != nil {
-		log.Fatal(err)
+	if packages.PrintErrors(pkgs) > 0 {
+		os.Exit(1)
 	}
+	pkg := pkgs[0]
 
 	var buf bytes.Buffer
 	fmt.Fprintf(&buf, `
@@ -114,10 +93,10 @@ package %s
 import (
 	%q
 )
-`[1:], pkg.Name(), fastjsonPath)
+`[1:], pkg.Types.Name(), fastjsonPath)
 
 	var generated int
-	for _, f := range files {
+	for _, f := range pkg.Syntax {
 		for _, decl := range f.Decls {
 			genDecl, ok := decl.(*ast.GenDecl)
 			if !ok || genDecl.Tok != token.TYPE {
@@ -128,7 +107,7 @@ import (
 				if !ok {
 					continue
 				}
-				obj := info.Defs[typeSpec.Name]
+				obj := pkg.TypesInfo.Defs[typeSpec.Name]
 				if obj == nil || !obj.Exported() {
 					continue
 				}

go.mod

@@ -1,3 +1,8 @@
 module go.elastic.co/fastjson
 
-require github.com/pkg/errors v0.8.0
+go 1.14
+
+require (
+	github.com/pkg/errors v0.8.0
+	golang.org/x/tools v0.0.0-20200509030707-2212a7e161a5
+)

go.sum

@@ -1,2 +1,22 @@
 github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/mod v0.2.0 h1:KU7oHjnv3XNWfa5COkzUifxZmxp1TyI7ImMXqFxLwvQ=
+golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
+golang.org/x/tools v0.0.0-20200509030707-2212a7e161a5 h1:MeC2gMlMdkd67dn17MEby3rGXRxZtWeiRXOnISfTQ74=
+golang.org/x/tools v0.0.0-20200509030707-2212a7e161a5/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=