Add binary removal delay on Windows to avoid access denied (#2351)

Co-authored-by: Polina Sokolova <polinasok@users.noreply.github.com>

cmd/dlv/dlv_test.go

@@ -170,13 +170,11 @@ func testOutput(t *testing.T, dlvbin, output string, delveCmds []string) (stdout
 
 	_, err = os.Stat(debugbin)
 	if err == nil {
-		if strings.ToLower(os.Getenv("TRAVIS")) == "true" && runtime.GOOS == "windows" {
+		// Sometimes delve on Windows can't remove the built binary before
-			// Sometimes delve on Travis on Windows can't remove the built binary before
+		// exiting and gets an "Access is denied" error when trying.
-			// exiting and gets an "Access is denied" error when trying.
+		// This used to make this test flaky. See: https://travis-ci.com/go-delve/delve/jobs/296325131)
-			// Just ignore it.
+		// But we have now added a delay to gobuild.Remove. If this flakes again,
-			// See: https://travis-ci.com/go-delve/delve/jobs/296325131
+		// adjust it. Leaving temporary files behind can be annoying to users.
-			return
-		}
 		t.Errorf("running %q: file %v was not deleted\nstdout is %q, stderr is %q", delveCmds, debugbin, stdout, stderr)
 		return
 	}

pkg/gobuild/gobuild.go

@@ -6,6 +6,8 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"runtime"
+	"time"
 
 	"github.com/go-delve/delve/pkg/config"
 	"github.com/go-delve/delve/pkg/goversion"
@@ -15,6 +17,12 @@ import (
 // This can be used to remove the temporary binary generated for the session.
 func Remove(path string) {
 	err := os.Remove(path)
+	// Open files can be removed on Unix, but not on Windows, where there also appears
+	// to be a delay in releasing the binary when the process exits. So we try again.
+	if err != nil && runtime.GOOS == "windows" {
+		time.Sleep(10 * time.Microsecond)
+		err = os.Remove(path)
+	}
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "could not remove %v: %v\n", path, err)
 	}