test: hide the cli help flag to avoid panic when running parallel (#2279)

Unfortunately the upstream package does not feel there [is a reason to
remove their global help flag variable
hack](urfave/cli#2176 (comment))
that can cause a panic when running in parallel, so this has us hide the
help flag for all commands when running the tests so that the code path
is skipped entirely

Author: G-Rath

cmd/osv-scanner/internal/cmd/run.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"io"
 	"log/slog"
+	"os"
 	"testing"
 
 	scalibr "github.com/google/osv-scalibr/version"
@@ -23,6 +24,14 @@ var (
 type CommandBuilder = func(stdout, stderr io.Writer) *cli.Command
 
 func Run(args []string, stdout, stderr io.Writer, commands []CommandBuilder) int {
+	// urfave/cli uses a global for its help flag which makes it possible for a nil
+	// pointer dereference if running in a parallel setting, which our test suite
+	// does, so this is used to hide the help flag so the global won't be used
+	// unless a particular env variable is set
+	//
+	// see https://github.com/urfave/cli/issues/2176
+	shouldHideHelp := testing.Testing() && os.Getenv("TEST_SHOW_HELP") != "true"
+
 	// --- Setup Logger ---
 	logHandler := cmdlogger.New(stdout, stderr)
 
@@ -50,14 +59,18 @@ func Run(args []string, stdout, stderr io.Writer, commands []CommandBuilder) int
 
 	cmds := make([]*cli.Command, 0, len(commands))
 	for _, cmd := range commands {
-		cmds = append(cmds, cmd(stdout, stderr))
+		c := cmd(stdout, stderr)
+		c.HideHelp = shouldHideHelp
+
+		cmds = append(cmds, c)
 	}
 
 	app := &cli.Command{
 		Name:           "osv-scanner",
 		Version:        version.OSVVersion,
 		Usage:          "scans various mediums for dependencies and checks them against the OSV database",
 		Suggest:        true,
+		HideHelp:       shouldHideHelp,
 		Writer:         stdout,
 		ErrWriter:      stderr,
 		DefaultCommand: "scan",

cmd/osv-scanner/main_test.go

@@ -9,6 +9,8 @@ import (
 
 //nolint:paralleltest
 func Test_run(t *testing.T) {
+	t.Setenv("TEST_SHOW_HELP", "true")
+
 	tests := []testcmd.Case{
 		{
 			Name: "",