RFC: Removed the default set PATH for Windows environments.

frontend/dockerfile/dockerfile_windows_test.go

@@ -0,0 +1,63 @@
+//go:build windows
+// +build windows
+
+package dockerfile
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/containerd/continuity/fs/fstest"
+	"github.com/moby/buildkit/client"
+	"github.com/moby/buildkit/frontend/dockerui"
+	"github.com/moby/buildkit/util/testutil/integration"
+	"github.com/stretchr/testify/require"
+	"github.com/tonistiigi/fsutil"
+)
+
+var windowsTests = integration.TestFuncs(
+	testSetPath,
+)
+
+func init() {
+	allTests = append(allTests, windowsTests...)
+}
+
+func testSetPath(t *testing.T, sb integration.Sandbox) {
+	f := getFrontend(t, sb)
+
+	dockerfile := []byte(`
+FROM nanoserver
+RUN setx PATH "C:\NewPath1;C:\NewPath2;%PATH%"
+RUN echo %PATH% > path.txt
+`)
+	dir := integration.Tmpdir(
+		t,
+		fstest.CreateFile("Dockerfile", dockerfile, 0600),
+	)
+	c, err := client.New(sb.Context(), sb.Address())
+	require.NoError(t, err)
+	defer c.Close()
+
+	destDir := t.TempDir()
+	_, err = f.Solve(sb.Context(), c, client.SolveOpt{
+		Exports: []client.ExportEntry{
+			{
+				Type:      client.ExporterLocal,
+				OutputDir: destDir,
+			},
+		},
+		LocalMounts: map[string]fsutil.FS{
+			dockerui.DefaultLocalNameDockerfile: dir,
+			dockerui.DefaultLocalNameContext:    dir,
+		},
+	}, nil)
+	require.NoError(t, err)
+
+	dt, err := os.ReadFile(filepath.Join(destDir, "path.txt"))
+	require.NoError(t, err)
+
+	envStr := string(dt)
+	require.Contains(t, envStr, "C:\\NewPath1;C:\\NewPath2")
+}

util/system/path.go

@@ -13,10 +13,8 @@ import (
 // ':' character .
 const DefaultPathEnvUnix = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
 
-// DefaultPathEnvWindows is windows style list of directories to search for
-// executables. Each directory is separated from the next by a colon
-// ';' character .
-const DefaultPathEnvWindows = "c:\\Windows\\System32;c:\\Windows"
+// DefaultPathEnvWindows is empty to allow windows to set the PATH when it runs
+const DefaultPathEnvWindows = ""
 
 func DefaultPathEnv(os string) string {
 	if os == "windows" {