feat: Add getters to error structs

command.go

@@ -1196,6 +1196,7 @@ func (c *Command) ValidateRequiredFlags() error {
 
 	if len(missingFlagNames) > 0 {
 		return &RequiredFlagError{
+			cmd:              c,
 			missingFlagNames: missingFlagNames,
 		}
 	}

errors.go

@@ -46,6 +46,28 @@ func (e *InvalidArgCountError) Error() string {
 	return fmt.Sprintf("accepts between %d and %d arg(s), received %d", e.atLeast, e.atMost, len(e.args))
 }
 
+// GetCommand returns the Command that the error occurred in.
+func (e *InvalidArgCountError) GetCommand() *Command {
+	return e.cmd
+}
+
+// GetArguments returns the invalid arguments.
+func (e *InvalidArgCountError) GetArguments() []string {
+	return e.args
+}
+
+// GetMinArgumentCount returns the minimum (inclusive) number of arguments
+// that the command requires. If there is no minimum, a value of -1 is returned.
+func (e *InvalidArgCountError) GetMinArgumentCount() int {
+	return e.atLeast
+}
+
+// GetMaxArgumentCount returns the maximum (inclusive) number of arguments
+// that the command requires. If there is no maximum, a value of -1 is returned.
+func (e *InvalidArgCountError) GetMaxArgumentCount() int {
+	return e.atMost
+}
+
 // InvalidArgCountError is the error returned an invalid argument is present.
 type InvalidArgValueError struct {
 	cmd         *Command
@@ -58,6 +80,21 @@ func (e *InvalidArgValueError) Error() string {
 	return fmt.Sprintf("invalid argument %q for %q%s", e.arg, e.cmd.CommandPath(), e.suggestions)
 }
 
+// GetCommand returns the Command that the error occurred in.
+func (e *InvalidArgValueError) GetCommand() *Command {
+	return e.cmd
+}
+
+// GetArgument returns the invalid argument.
+func (e *InvalidArgValueError) GetArgument() string {
+	return e.arg
+}
+
+// GetSuggestions returns suggestions, if there are any.
+func (e *InvalidArgValueError) GetSuggestions() string {
+	return e.suggestions
+}
+
 // UnknownSubcommandError is the error returned when a subcommand can not be
 // found.
 type UnknownSubcommandError struct {
@@ -66,6 +103,21 @@ type UnknownSubcommandError struct {
 	suggestions string
 }
 
+// GetCommand returns the Command that the error occurred in.
+func (e *UnknownSubcommandError) GetCommand() *Command {
+	return e.cmd
+}
+
+// GetSubcommand returns the unknown subcommand name.
+func (e *UnknownSubcommandError) GetSubcommand() string {
+	return e.subcmd
+}
+
+// GetSuggestions returns suggestions, if there are any.
+func (e *UnknownSubcommandError) GetSuggestions() string {
+	return e.suggestions
+}
+
 // Error implements error.
 func (e *UnknownSubcommandError) Error() string {
 	return fmt.Sprintf("unknown command %q for %q%s", e.subcmd, e.cmd.CommandPath(), e.suggestions)
@@ -73,6 +125,7 @@ func (e *UnknownSubcommandError) Error() string {
 
 // RequiredFlagError is the error returned when a required flag is not set.
 type RequiredFlagError struct {
+	cmd              *Command
 	missingFlagNames []string
 }
 
@@ -81,31 +134,72 @@ func (e *RequiredFlagError) Error() string {
 	return fmt.Sprintf(`required flag(s) "%s" not set`, strings.Join(e.missingFlagNames, `", "`))
 }
 
+// GetCommand returns the Command that the error occurred in.
+func (e *RequiredFlagError) GetCommand() *Command {
+	return e.cmd
+}
+
+// GetFlags returns the names of the missing flags.
+func (e *RequiredFlagError) GetFlags() []string {
+	return e.missingFlagNames
+}
+
 // FlagGroupError is the error returned when mutually-required or
 // mutually-exclusive flags are not properly specified.
 type FlagGroupError struct {
+	cmd           *Command
 	flagList      string
-	flagGroupType flagGroupType
+	flagGroupType FlagGroupType
 	problemFlags  []string
 }
 
-// flagGroupType identifies which failed validation caused a FlagGroupError.
-type flagGroupType string
+// GetCommand returns the Command that the error occurred in.
+func (e *FlagGroupError) GetCommand() *Command {
+	return e.cmd
+}
+
+// GetFlagList returns the flags in the group.
+func (e *FlagGroupError) GetFlags() []string {
+	return strings.Split(e.flagList, " ")
+}
+
+// GetFlagGroupType returns the type of flag group causing the error.
+//
+// Valid types are:
+//   - FlagsAreMutuallyExclusive for mutually-exclusive flags.
+//   - FlagsAreRequiredTogether for mutually-required flags.
+//   - FlagsAreOneRequired for flags where at least one must be present.
+func (e *FlagGroupError) GetFlagGroupType() FlagGroupType {
+	return e.flagGroupType
+}
+
+// GetProblemFlags returns the flags causing the error.
+//
+// For flag groups where:
+//   - FlagsAreMutuallyExclusive, these are all the flags set.
+//   - FlagsAreRequiredTogether, these are the missing flags.
+//   - FlagsAreOneRequired, this is empty.
+func (e *FlagGroupError) GetProblemFlags() []string {
+	return e.problemFlags
+}
+
+// FlagGroupType identifies which failed validation caused a FlagGroupError.
+type FlagGroupType string
 
 const (
-	flagGroupIsExclusive   flagGroupType = "if any is set, none of the others can be"
-	flagGroupIsRequired    flagGroupType = "if any is set, they must all be set"
-	flagGroupIsOneRequired flagGroupType = "at least one of the flags is required"
+	FlagsAreMutuallyExclusive FlagGroupType = "if any is set, none of the others can be"
+	FlagsAreRequiredTogether  FlagGroupType = "if any is set, they must all be set"
+	FlagsAreOneRequired       FlagGroupType = "at least one of the flags is required"
 )
 
 // Error implements error.
 func (e *FlagGroupError) Error() string {
 	switch e.flagGroupType {
-	case flagGroupIsRequired:
+	case FlagsAreRequiredTogether:
 		return fmt.Sprintf("if any flags in the group [%v] are set they must all be set; missing %v", e.flagList, e.problemFlags)
-	case flagGroupIsOneRequired:
+	case FlagsAreOneRequired:
 		return fmt.Sprintf("at least one of the flags in the group [%v] is required", e.flagList)
-	case flagGroupIsExclusive:
+	case FlagsAreMutuallyExclusive:
 		return fmt.Sprintf("if any flags in the group [%v] are set none of the others can be; %v were all set", e.flagList, e.problemFlags)
 	}
 

flag_groups.go

@@ -97,12 +97,15 @@ func (c *Command) ValidateFlagGroups() error {
 	})
 
 	if err := validateRequiredFlagGroups(groupStatus); err != nil {
+		err.cmd = c
 		return err
 	}
 	if err := validateOneRequiredFlagGroups(oneRequiredGroupStatus); err != nil {
+		err.cmd = c
 		return err
 	}
 	if err := validateExclusiveFlagGroups(mutuallyExclusiveGroupStatus); err != nil {
+		err.cmd = c
 		return err
 	}
 	return nil
@@ -141,7 +144,7 @@ func processFlagForGroupAnnotation(flags *flag.FlagSet, pflag *flag.Flag, annota
 	}
 }
 
-func validateRequiredFlagGroups(data map[string]map[string]bool) error {
+func validateRequiredFlagGroups(data map[string]map[string]bool) *FlagGroupError {
 	keys := sortedKeys(data)
 	for _, flagList := range keys {
 		flagnameAndStatus := data[flagList]
@@ -160,7 +163,7 @@ func validateRequiredFlagGroups(data map[string]map[string]bool) error {
 		sort.Strings(unset)
 		return &FlagGroupError{
 			flagList:      flagList,
-			flagGroupType: flagGroupIsRequired,
+			flagGroupType: FlagsAreRequiredTogether,
 			problemFlags:  unset,
 		}
 	}
@@ -168,7 +171,7 @@ func validateRequiredFlagGroups(data map[string]map[string]bool) error {
 	return nil
 }
 
-func validateOneRequiredFlagGroups(data map[string]map[string]bool) error {
+func validateOneRequiredFlagGroups(data map[string]map[string]bool) *FlagGroupError {
 	keys := sortedKeys(data)
 	for _, flagList := range keys {
 		flagnameAndStatus := data[flagList]
@@ -186,13 +189,13 @@ func validateOneRequiredFlagGroups(data map[string]map[string]bool) error {
 		sort.Strings(set)
 		return &FlagGroupError{
 			flagList:      flagList,
-			flagGroupType: flagGroupIsOneRequired,
+			flagGroupType: FlagsAreOneRequired,
 		}
 	}
 	return nil
 }
 
-func validateExclusiveFlagGroups(data map[string]map[string]bool) error {
+func validateExclusiveFlagGroups(data map[string]map[string]bool) *FlagGroupError {
 	keys := sortedKeys(data)
 	for _, flagList := range keys {
 		flagnameAndStatus := data[flagList]
@@ -210,7 +213,7 @@ func validateExclusiveFlagGroups(data map[string]map[string]bool) error {
 		sort.Strings(set)
 		return &FlagGroupError{
 			flagList:      flagList,
-			flagGroupType: flagGroupIsExclusive,
+			flagGroupType: FlagsAreMutuallyExclusive,
 			problemFlags:  set,
 		}
 	}