fix: keep -h reserved for help flag

The previous change avoided a panic by falling back to a long-only help flag
when shorthand "h" was already in use. Reviewer feedback noted this would be
a behavior change: -h is intentionally reserved for help, and the panic acts
as an early signal of a developer conflict.

Restore the panic on shorthand conflicts, but make it explicit and clearer by
detecting an existing -h flag and panicking with a targeted message. Update
the test to assert the reserved-shorthand behavior.

Refs: spf13#2367
Context: reviewer feedback on PR

Author: dimitar-trifonov

command.go

@@ -1226,11 +1226,10 @@ func (c *Command) InitDefaultHelpFlag() {
 		} else {
 			usage += name
 		}
-		if c.Flags().ShorthandLookup("h") == nil {
-			c.Flags().BoolP(helpFlagName, "h", false, usage)
-		} else {
-			c.Flags().Bool(helpFlagName, false, usage)
+		if f := c.Flags().ShorthandLookup("h"); f != nil {
+			panic(fmt.Sprintf("shorthand '-h' is reserved for the help flag, but is already used by flag '%s'", f.Name))
 		}
+		c.Flags().BoolP(helpFlagName, "h", false, usage)
 		_ = c.Flags().SetAnnotation(helpFlagName, FlagSetByCobraAnnotation, []string{"true"})
 	}
 }

command_test.go

@@ -939,23 +939,19 @@ func TestInitHelpFlagMergesFlags(t *testing.T) {
 }
 
 // related to https://github.com/spf13/cobra/issues/2359
-func TestInitDefaultHelpFlagDoesNotPanicWhenHShorthandAlreadyUsed(t *testing.T) {
+func TestInitDefaultHelpFlagPanicsWhenHShorthandAlreadyUsed(t *testing.T) {
 	cmd := &Command{Use: "root"}
 
 	cmd.PersistentFlags().BoolP("ayuda", "h", false, "help")
 
 	func() {
 		defer func() {
-			if r := recover(); r != nil {
-				t.Fatalf("expected InitDefaultHelpFlag not to panic, got: %v", r)
+			if r := recover(); r == nil {
+				t.Fatalf("expected InitDefaultHelpFlag to panic")
 			}
 		}()
 		cmd.InitDefaultHelpFlag()
 	}()
-
-	if cmd.Flags().Lookup("help") == nil {
-		t.Fatalf("expected default help flag to be defined")
-	}
 }
 
 func TestHelpCommandExecuted(t *testing.T) {