importer_test.go

     1  // Copyright 2017 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package importer
     6  
     7  import (
     8  	"go/build"
     9  	"go/token"
    10  	"internal/testenv"
    11  	"io"
    12  	"os"
    13  	"strings"
    14  	"testing"
    15  )
    16  
    17  func TestMain(m *testing.M) {
    18  	build.Default.GOROOT = testenv.GOROOT(nil)
    19  	os.Exit(m.Run())
    20  }
    21  
    22  func TestForCompiler(t *testing.T) {
    23  	testenv.MustHaveGoBuild(t)
    24  
    25  	const thePackage = "math/big"
    26  	out, err := testenv.Command(t, testenv.GoToolPath(t), "list", "-export", "-f={{context.Compiler}}:{{.Export}}", thePackage).CombinedOutput()
    27  	if err != nil {
    28  		t.Fatalf("go list %s: %v\n%s", thePackage, err, out)
    29  	}
    30  	export := strings.TrimSpace(string(out))
    31  	compiler, target, _ := strings.Cut(export, ":")
    32  
    33  	if compiler == "gccgo" {
    34  		t.Skip("golang.org/issue/22500")
    35  	}
    36  
    37  	fset := token.NewFileSet()
    38  
    39  	t.Run("LookupDefault", func(t *testing.T) {
    40  		imp := ForCompiler(fset, compiler, nil)
    41  		pkg, err := imp.Import(thePackage)
    42  		if err != nil {
    43  			t.Fatal(err)
    44  		}
    45  		if pkg.Path() != thePackage {
    46  			t.Fatalf("Path() = %q, want %q", pkg.Path(), thePackage)
    47  		}
    48  
    49  		// Check that the fileset positions are accurate.
    50  		// https://github.com/golang/go#28995
    51  		mathBigInt := pkg.Scope().Lookup("Int")
    52  		posn := fset.Position(mathBigInt.Pos()) // "$GOROOT/src/math/big/int.go:25:1"
    53  		filename := strings.Replace(posn.Filename, "$GOROOT", testenv.GOROOT(t), 1)
    54  		data, err := os.ReadFile(filename)
    55  		if err != nil {
    56  			t.Fatalf("can't read file containing declaration of math/big.Int: %v", err)
    57  		}
    58  		lines := strings.Split(string(data), "\n")
    59  		if posn.Line > len(lines) || !strings.HasPrefix(lines[posn.Line-1], "type Int") {
    60  			t.Fatalf("Object %v position %s does not contain its declaration",
    61  				mathBigInt, posn)
    62  		}
    63  	})
    64  
    65  	t.Run("LookupCustom", func(t *testing.T) {
    66  		// TODO(mdempsky): Decide whether to remove this test, or to fix
    67  		// support for it in unified IR. It's not clear that we actually
    68  		// need to support importing "math/big" as "math/bigger", for
    69  		// example. cmd/link no longer supports that.
    70  		if true /* was buildcfg.Experiment.Unified */ {
    71  			t.Skip("not supported by GOEXPERIMENT=unified; see go.dev/cl/406319")
    72  		}
    73  
    74  		lookup := func(path string) (io.ReadCloser, error) {
    75  			if path != "math/bigger" {
    76  				t.Fatalf("lookup called with unexpected path %q", path)
    77  			}
    78  			f, err := os.Open(target)
    79  			if err != nil {
    80  				t.Fatal(err)
    81  			}
    82  			return f, nil
    83  		}
    84  		imp := ForCompiler(fset, compiler, lookup)
    85  		pkg, err := imp.Import("math/bigger")
    86  		if err != nil {
    87  			t.Fatal(err)
    88  		}
    89  		// Even though we open math/big.a, the import request was for math/bigger
    90  		// and that should be recorded in pkg.Path(), at least for the gc toolchain.
    91  		if pkg.Path() != "math/bigger" {
    92  			t.Fatalf("Path() = %q, want %q", pkg.Path(), "math/bigger")
    93  		}
    94  	})
    95  }
    96
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