simplify command alias logic + remove deprecation warning for root command

Signed-off-by: Alex Goodman <alex.goodman@anchore.com>

README.md

@@ -22,6 +22,9 @@ If you encounter an issue, please [let us know using the issue tracker](https://
 To generate an SBOM for a Docker or OCI image:
 ```
 syft packages <image>
+
+# note: this is the same as not providing the "packages" subcommand
+syft <image>
 ```
 
 The above output includes only software that is visible in the container (i.e., the squashed representation of the image).

cmd/cmd.go

@@ -3,7 +3,6 @@ package cmd
 import (
 	"fmt"
 	"os"
-	"strings"
 
 	"github.com/spf13/cobra"
 
@@ -33,10 +32,6 @@ func init() {
 	)
 }
 
-// provided to disambiguate the root vs packages command, whichever is indicated by the cli args will be set here.
-// TODO: when the root alias command is removed, this variable can be removed
-var activeCmd *cobra.Command
-
 func Execute() {
 	if err := rootCmd.Execute(); err != nil {
 		fmt.Fprintln(os.Stderr, color.Red.Sprint(err.Error()))
@@ -48,30 +43,9 @@ func Execute() {
 // be done without determining what the primary command that the config options should be bound to since there are
 // shared concerns (the root-packages alias).
 func initCmdAliasBindings() {
-	// TODO: when the root alias command is removed, this function (hack) can be removed
-
-	// map of all commands except for root
-	commands := make(map[string]*cobra.Command)
-	for _, c := range rootCmd.Commands() {
-		name := strings.Split(c.Use, " ")[0]
-		commands[name] = c
-	}
-
-	activeCmd = rootCmd
-	for i, a := range os.Args {
-		if i == 0 {
-			// don't consider the bin
-			continue
-		}
-		// check to see if this argument may be a command
-		if c, exists := commands[a]; exists {
-			activeCmd = c
-		}
-	}
-
-	if activeCmd == rootCmd {
-		// note: cobra supports command deprecation, however the command name is empty and does not report to stderr
-		fmt.Fprintln(os.Stderr, color.New(color.Bold, color.Red).Sprintf("The root command is deprecated, please use the 'packages' subcommand"))
+	activeCmd, _, err := rootCmd.Find(os.Args[1:])
+	if err != nil {
+		panic(err)
 	}
 
 	if activeCmd == packagesCmd || activeCmd == rootCmd {
@@ -81,11 +55,13 @@ func initCmdAliasBindings() {
 		// reading the application configuration, which implies that it must be an initializer (or rewrite the command
 		// initialization structure against typical patterns used with cobra, which is somewhat extreme for a
 		// temporary alias)
-		if err := bindConfigOptions(activeCmd.Flags()); err != nil {
+		if err = bindPackagesConfigOptions(activeCmd.Flags()); err != nil {
 			panic(err)
 		}
 	} else {
-		if err := bindConfigOptions(packagesCmd.Flags()); err != nil {
+		// even though the root command or packages command is NOT being run, we still need default bindings
+		// such that application config parsing passes.
+		if err = bindPackagesConfigOptions(packagesCmd.Flags()); err != nil {
 			panic(err)
 		}
 	}

cmd/packages.go

@@ -138,7 +138,7 @@ func setPackageFlags(flags *pflag.FlagSet) {
 	)
 }
 
-func bindConfigOptions(flags *pflag.FlagSet) error {
+func bindPackagesConfigOptions(flags *pflag.FlagSet) error {
 	///////// Formatting & Input options //////////////////////////////////////////////
 
 	if err := viper.BindPFlag("package.cataloger.scope", flags.Lookup("scope")); err != nil {

test/cli/root_cmd_test.go

@@ -9,25 +9,50 @@ import (
 
 func TestRootCmdAliasesToPackagesSubcommand(t *testing.T) {
 	request := "docker-archive:" + getFixtureImage(t, "image-pkg-coverage")
-	deprecationWarning := "The root command is deprecated"
 
-	_, aliasStdout, aliasStderr := runSyftCommand(t, nil, request)
-
-	if !strings.Contains(aliasStderr, deprecationWarning) {
-		t.Errorf("missing root-packages alias deprecation warning")
+	tests := []struct {
+		name       string
+		env        map[string]string
+		assertions []traitAssertion
+	}{
+		{
+			name: "go-case",
+			assertions: []traitAssertion{
+				assertTableReport,
+				assertSuccessfulReturnCode,
+			},
+		},
+		{
+			name: "respond-to-output-binding",
+			env: map[string]string{
+				"SYFT_OUTPUT": "text",
+			},
+			assertions: []traitAssertion{
+				assertInOutput("[Image]"),
+				assertSuccessfulReturnCode,
+			},
+		},
 	}
 
-	_, pkgsStdout, pkgsStderr := runSyftCommand(t, nil, "packages", request)
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			aliasCmd, aliasStdout, aliasStderr := runSyftCommand(t, test.env, request)
+			for _, traitFn := range test.assertions {
+				traitFn(t, aliasStdout, aliasStderr, aliasCmd.ProcessState.ExitCode())
+			}
 
-	if strings.Contains(pkgsStderr, deprecationWarning) {
-		t.Errorf("packages command should not have deprecation warning")
-	}
+			pkgCmd, pkgsStdout, pkgsStderr := runSyftCommand(t, test.env, "packages", request)
+			for _, traitFn := range test.assertions {
+				traitFn(t, pkgsStdout, pkgsStderr, pkgCmd.ProcessState.ExitCode())
+			}
 
-	if aliasStdout != pkgsStdout {
-		t.Errorf("packages and root command should have same report output but do not!")
-		dmp := diffmatchpatch.New()
-		diffs := dmp.DiffMain(aliasStdout, pkgsStdout, true)
-		t.Error(dmp.DiffPrettyText(diffs))
+			if aliasStdout != pkgsStdout {
+				t.Errorf("packages and root command should have same report output but do not!")
+				dmp := diffmatchpatch.New()
+				diffs := dmp.DiffMain(aliasStdout, pkgsStdout, true)
+				t.Error(dmp.DiffPrettyText(diffs))
+			}
+		})
 	}
 }