fix(bonfire): recognise cobra's unknown command error once in Execute (IN-03, quick-261028-rqd)

modules/bonfire/errors.go

@@ -12,6 +12,7 @@ import (
 	"git.golem15.com/golem15/summercms/internal/argmask"
 	"git.golem15.com/golem15/summercms/modules/sunscreen"
 	"github.com/charmbracelet/colorprofile"
+	"github.com/spf13/cobra"
 )
 
 // UsageError marks a mistake in how a command was called: an unknown
@@ -40,13 +41,39 @@ func Usage(err error) error {
 	return &UsageError{Err: err}
 }
 
-// isUsage reports a UsageError in the chain or cobra's unknown command error.
+// isUsage reports a UsageError in the chain. cobra's unknown command error
+// counts only after Execute has converted it (unknownCommand).
 func isUsage(err error) bool {
 	var ue *UsageError
-	if errors.As(err, &ue) {
-		return true
+	return errors.As(err, &ue)
+}
+
+// unknownCommandError is cobra's unknown command error once Execute has
+// confirmed it came from cobra: Error keeps cobra's text, name and
+// suggestions are read from it once.
+type unknownCommandError struct {
+	msg         string
+	name        string
+	suggestions []string
+}
+
+func (e *unknownCommandError) Error() string { return e.msg }
+
+// unknownCommand converts err into a UsageError around an
+// unknownCommandError when it is cobra's unknown command error for args:
+// root.Find on the same args fails at the root with the same message, so
+// cobra rejected the command word and no command ran. Every other error,
+// including a command's own error worded the same way, is returned as is.
+func unknownCommand(root *cobra.Command, args []string, err error) error {
+	if err == nil || root == nil {
+		return err
 	}
-	return strings.HasPrefix(err.Error(), "unknown command")
+	cmd, _, ferr := root.Find(args)
+	if ferr == nil || cmd != root || ferr.Error() != err.Error() {
+		return err
+	}
+	name, suggestions := parseUnknownCommand(err.Error())
+	return &UsageError{Err: &unknownCommandError{msg: err.Error(), name: name, suggestions: suggestions}}
 }
 
 // HintError adds an explanation and a command to try to an error. The error
@@ -169,9 +196,10 @@ func WithExitCode(err error, code int) error {
 // and the message, the explanation and the Try lines of a HintError ({bin}
 // replaced by summer or bin/<name>, for the root named name), then "Run with
 // -v for details." at verbosity 0 or the wrapped error chain under "Caused
-// by:" at -v and above. cobra's unknown command error becomes `Command "x"
-// is not defined.` with its suggestions as Try lines, and other usage errors
-// suggest the command's help. Every message passes through sunscreen.Scrub,
+// by:" at -v and above. An unknown command, as recognised by Execute,
+// becomes `Command "x" is not defined.` with cobra's suggestions as Try
+// lines, and other usage errors suggest the command's help. A raw cobra
+// error passed in directly keeps cobra's text. Every message passes through sunscreen.Scrub,
 // and every line through Sanitize.
 // Errors wrapped by Reported print nothing.
 func RenderError(w io.Writer, name string, err error, g Globals) {
@@ -189,12 +217,12 @@ func RenderError(w io.Writer, name string, err error, g Globals) {
 	if errors.As(err, &hint) {
 		explanation, try = hint.Explanation, hint.Try
 	}
-	if strings.HasPrefix(message, "unknown command") {
-		cmdName, suggestions := parseUnknownCommand(message)
-		message = `Command "` + cmdName + `" is not defined.`
+	var unknown *unknownCommandError
+	if errors.As(err, &unknown) {
+		message = `Command "` + unknown.name + `" is not defined.`
 		if try == "" {
 			var lines []string
-			for _, s := range suggestions {
+			for _, s := range unknown.suggestions {
 				lines = append(lines, "{bin} "+s)
 			}
 			if len(lines) == 0 {