From 64f9b0cc910c1f1bb99b746663866f16c816953b Mon Sep 17 00:00:00 2001
From: Vadim Shtayura <vadimsh@chromium.org>
Date: Thu, 31 Jan 2019 22:41:36 -0800
Subject: [PATCH] Make default DataFile work with GOPATH with multiple entries.

---
 starlarktest/starlarktest.go | 10 +++++++++-
 syntax/parse_test.go         | 10 +---------
 syntax/scan_test.go          | 10 +++++++++-
 3 files changed, 19 insertions(+), 11 deletions(-)

diff --git a/starlarktest/starlarktest.go b/starlarktest/starlarktest.go
index 5436d225..a8ca851f 100644
--- a/starlarktest/starlarktest.go
+++ b/starlarktest/starlarktest.go
@@ -16,6 +16,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/build"
+	"os"
 	"path/filepath"
 	"regexp"
 	"sync"
@@ -133,5 +134,12 @@ func freeze(thread *starlark.Thread, _ *starlark.Builtin, args starlark.Tuple, k
 // 'go build', under which a test runs in its package directory,
 // and Blaze, under which a test runs in the root of the tree.
 var DataFile = func(pkgdir, filename string) string {
-	return filepath.Join(build.Default.GOPATH, "src/go.starlark.net", pkgdir, filename)
+	rel := filepath.Join("go.starlark.net", pkgdir, filename)
+	for _, p := range build.Default.SrcDirs() {
+		full := filepath.Join(p, rel)
+		if _, err := os.Stat(full); err == nil {
+			return full
+		}
+	}
+	panic(fmt.Sprintf("could not find %s", rel))
 }
diff --git a/syntax/parse_test.go b/syntax/parse_test.go
index 309e249c..9aa71ee0 100644
--- a/syntax/parse_test.go
+++ b/syntax/parse_test.go
@@ -8,9 +8,7 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
-	"go/build"
 	"io/ioutil"
-	"path/filepath"
 	"reflect"
 	"strings"
 	"testing"
@@ -481,14 +479,8 @@ File
 	}
 }
 
-// dataFile is the same as starlarktest.DataFile.
-// We make a copy to avoid a dependency cycle.
-var dataFile = func(pkgdir, filename string) string {
-	return filepath.Join(build.Default.GOPATH, "src/go.starlark.net", pkgdir, filename)
-}
-
 func BenchmarkParse(b *testing.B) {
-	filename := dataFile("syntax", "testdata/scan.star")
+	filename := starlarktest.DataFile("syntax", "testdata/scan.star")
 	b.StopTimer()
 	data, err := ioutil.ReadFile(filename)
 	if err != nil {
diff --git a/syntax/scan_test.go b/syntax/scan_test.go
index 06f42dbd..6861e9cf 100644
--- a/syntax/scan_test.go
+++ b/syntax/scan_test.go
@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"go/build"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"testing"
 )
@@ -228,7 +229,14 @@ pass`, "pass newline pass EOF"}, // consecutive newlines are consolidated
 // dataFile is the same as starlarktest.DataFile.
 // We make a copy to avoid a dependency cycle.
 var dataFile = func(pkgdir, filename string) string {
-	return filepath.Join(build.Default.GOPATH, "src/go.starlark.net", pkgdir, filename)
+	rel := filepath.Join("go.starlark.net", pkgdir, filename)
+	for _, p := range build.Default.SrcDirs() {
+		full := filepath.Join(p, rel)
+		if _, err := os.Stat(full); err == nil {
+			return full
+		}
+	}
+	panic(fmt.Sprintf("could not find %s", rel))
 }
 
 func BenchmarkScan(b *testing.B) {