Micro-optimizations

args.go

@@ -52,9 +52,9 @@ func OnlyValidArgs(cmd *Command, args []string) error {
 	if len(cmd.ValidArgs) > 0 {
 		// Remove any description that may be included in ValidArgs.
 		// A description is following a tab character.
-		var validArgs []string
+		validArgs := make([]string, 0, len(cmd.ValidArgs))
 		for _, v := range cmd.ValidArgs {
-			validArgs = append(validArgs, strings.Split(v, "\t")[0])
+			validArgs = append(validArgs, strings.SplitN(v, "\t", 2)[0])
 		}
 		for _, v := range args {
 			if !stringInSlice(v, validArgs) {

bash_completions.go

@@ -621,7 +621,7 @@ func writeRequiredNouns(buf io.StringWriter, cmd *Command) {
 	for _, value := range cmd.ValidArgs {
 		// Remove any description that may be included following a tab character.
 		// Descriptions are not supported by bash completion.
-		value = strings.Split(value, "\t")[0]
+		value = strings.SplitN(value, "\t", 2)[0]
 		WriteStringAndCheck(buf, fmt.Sprintf("    must_have_one_noun+=(%q)\n", value))
 	}
 	if cmd.ValidArgsFunction != nil {

cobra.go

@@ -188,8 +188,6 @@ func ld(s, t string, ignoreCase bool) int {
 	d := make([][]int, len(s)+1)
 	for i := range d {
 		d[i] = make([]int, len(t)+1)
-	}
-	for i := range d {
 		d[i][0] = i
 	}
 	for j := range d[0] {

command.go

@@ -701,7 +701,7 @@ Loop:
 			// This is not a flag or a flag value. Check to see if it matches what we're looking for, and if so,
 			// return the args, excluding the one at this position.
 			if s == x {
-				ret := []string{}
+				ret := make([]string, 0, len(args)-1)
 				ret = append(ret, args[:pos]...)
 				ret = append(ret, args[pos+1:]...)
 				return ret
@@ -749,14 +749,14 @@ func (c *Command) findSuggestions(arg string) string {
 	if c.SuggestionsMinimumDistance <= 0 {
 		c.SuggestionsMinimumDistance = 2
 	}
-	suggestionsString := ""
+	var sb strings.Builder
 	if suggestions := c.SuggestionsFor(arg); len(suggestions) > 0 {
-		suggestionsString += "\n\nDid you mean this?\n"
+		sb.WriteString("\n\nDid you mean this?\n")
 		for _, s := range suggestions {
-			suggestionsString += fmt.Sprintf("\t%v\n", s)
+			_, _ = fmt.Fprintf(&sb, "\t%v\n", s)
 		}
 	}
-	return suggestionsString
+	return sb.String()
 }
 
 func (c *Command) findNext(next string) *Command {

completions.go

@@ -217,23 +217,23 @@ func (c *Command) initCompleteCmd(args []string) {
 			}
 
 			noDescriptions := (cmd.CalledAs() == ShellCompNoDescRequestCmd)
+			noActiveHelp := GetActiveHelpConfig(finalCmd) == activeHelpGlobalDisable
+			out := finalCmd.OutOrStdout()
 			for _, comp := range completions {
-				if GetActiveHelpConfig(finalCmd) == activeHelpGlobalDisable {
-					// Remove all activeHelp entries in this case
-					if strings.HasPrefix(comp, activeHelpMarker) {
-						continue
-					}
+				if noActiveHelp && strings.HasPrefix(comp, activeHelpMarker) {
+					// Remove all activeHelp entries if it's disabled.
+					continue
 				}
 				if noDescriptions {
 					// Remove any description that may be included following a tab character.
-					comp = strings.Split(comp, "\t")[0]
+					comp = strings.SplitN(comp, "\t", 2)[0]
 				}
 
 				// Make sure we only write the first line to the output.
 				// This is needed if a description contains a linebreak.
 				// Otherwise the shell scripts will interpret the other lines as new flags
 				// and could therefore provide a wrong completion.
-				comp = strings.Split(comp, "\n")[0]
+				comp = strings.SplitN(comp, "\n", 2)[0]
 
 				// Finally trim the completion.  This is especially important to get rid
 				// of a trailing tab when there are no description following it.
@@ -242,14 +242,14 @@ func (c *Command) initCompleteCmd(args []string) {
 				// although there is no description).
 				comp = strings.TrimSpace(comp)
 
-				// Print each possible completion to stdout for the completion script to consume.
-				fmt.Fprintln(finalCmd.OutOrStdout(), comp)
+				// Print each possible completion to the output for the completion script to consume.
+				fmt.Fprintln(out, comp)
 			}
 
 			// As the last printout, print the completion directive for the completion script to parse.
 			// The directive integer must be that last character following a single colon (:).
 			// The completion script expects :<directive>
-			fmt.Fprintf(finalCmd.OutOrStdout(), ":%d\n", directive)
+			fmt.Fprintf(out, ":%d\n", directive)
 
 			// Print some helpful info to stderr for the user to understand.
 			// Output from stderr must be ignored by the completion script.

flag_groups.go

@@ -130,7 +130,7 @@ func processFlagForGroupAnnotation(flags *flag.FlagSet, pflag *flag.Flag, annota
 					continue
 				}
 
-				groupStatus[group] = map[string]bool{}
+				groupStatus[group] = make(map[string]bool, len(flagnames))
 				for _, name := range flagnames {
 					groupStatus[group][name] = false
 				}
@@ -253,17 +253,17 @@ func (c *Command) enforceFlagGroupsForCompletion() {
 	// If none of the flags of a one-required group are present, we make all the flags
 	// of that group required so that the shell completion suggests them automatically
 	for flagList, flagnameAndStatus := range oneRequiredGroupStatus {
-		set := 0
+		isSet := false
 
-		for _, isSet := range flagnameAndStatus {
+		for _, isSet = range flagnameAndStatus {
 			if isSet {
-				set++
+				break
 			}
 		}
 
 		// None of the flags of the group are set, mark all flags in the group
 		// as required
-		if set == 0 {
+		if !isSet {
 			for _, fName := range strings.Split(flagList, " ") {
 				_ = c.MarkFlagRequired(fName)
 			}