diff options
| -rw-r--r-- | parse.go | 126 | ||||
| -rw-r--r-- | parse_test.go | 36 | ||||
| -rw-r--r-- | reflect.go | 8 | ||||
| -rw-r--r-- | usage_test.go | 2 |
4 files changed, 100 insertions, 72 deletions
@@ -43,18 +43,19 @@ func (p path) Child(f reflect.StructField) path { // spec represents a command line option type spec struct { - dest path - field reflect.StructField // the struct field from which this option was created - long string // the --long form for this option, or empty if none - short string // the -s short form for this option, or empty if none - cardinality cardinality // determines how many tokens will be present (possible values: zero, one, multiple) - required bool // if true, this option must be present on the command line - positional bool // if true, this option will be looked for in the positional flags - separate bool // if true, each slice and map entry will have its own --flag - help string // the help text for this option - env string // the name of the environment variable for this option, or empty for none - defaultVal string // default value for this option - placeholder string // name of the data in help + dest path + field reflect.StructField // the struct field from which this option was created + long string // the --long form for this option, or empty if none + short string // the -s short form for this option, or empty if none + cardinality cardinality // determines how many tokens will be present (possible values: zero, one, multiple) + required bool // if true, this option must be present on the command line + positional bool // if true, this option will be looked for in the positional flags + separate bool // if true, each slice and map entry will have its own --flag + help string // the help text for this option + env string // the name of the environment variable for this option, or empty for none + defaultValue reflect.Value // default value for this option + defaultString string // default value for this option, in string form to be displayed in help text + placeholder string // name of the data in help } // command represents a named subcommand, or the top-level command @@ -210,39 +211,30 @@ func NewParser(config Config, dests ...interface{}) (*Parser, error) { // for backwards compatibility, add nonzero field values as defaults for _, spec := range cmd.specs { - // do not read default when UnmarshalText is implemented but not MarshalText - if isTextUnmarshaler(spec.field.Type) && !isTextMarshaler(spec.field.Type) { + // get the value + v := p.val(spec.dest) + if !v.IsValid() { continue } - // do not process types that require multiple values - cardinality, _ := cardinalityOf(spec.field.Type) - if cardinality != one { + // if the value is the "zero value" (e.g. nil pointer, empty struct) then ignore + if isZero(v) { continue } - // get the value - v := p.val(spec.dest) - if !v.IsValid() { - continue - } + // store as a default + spec.defaultValue = v + // we need a string to display in help text // if MarshalText is implemented then use that if m, ok := v.Interface().(encoding.TextMarshaler); ok { - if v.IsNil() { - continue - } s, err := m.MarshalText() if err != nil { return nil, fmt.Errorf("%v: error marshaling default value to string: %v", spec.dest, err) } - spec.defaultVal = string(s) - continue - } - - // finally, use the value as a default if it is non-zero - if !isZero(v) { - spec.defaultVal = fmt.Sprintf("%v", v) + spec.defaultString = string(s) + } else { + spec.defaultString = fmt.Sprintf("%v", v) } } @@ -311,11 +303,6 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) { spec.help = help } - defaultVal, hasDefault := field.Tag.Lookup("default") - if hasDefault { - spec.defaultVal = defaultVal - } - // Look at the tag var isSubcommand bool // tracks whether this field is a subcommand for _, key := range strings.Split(tag, ",") { @@ -342,11 +329,6 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) { } spec.short = key[1:] case key == "required": - if hasDefault { - errs = append(errs, fmt.Sprintf("%s.%s: 'required' cannot be used when a default value is specified", - t.Name(), field.Name)) - return false - } spec.required = true case key == "positional": spec.positional = true @@ -395,27 +377,60 @@ func cmdFromStruct(name string, dest path, t reflect.Type) (*command, error) { spec.placeholder = strings.ToUpper(spec.field.Name) } - // Check whether this field is supported. It's good to do this here rather than + // if this is a subcommand then we've done everything we need to do + if isSubcommand { + return false + } + + // check whether this field is supported. It's good to do this here rather than // wait until ParseValue because it means that a program with invalid argument // fields will always fail regardless of whether the arguments it received // exercised those fields. - if !isSubcommand { - cmd.specs = append(cmd.specs, &spec) + var err error + spec.cardinality, err = cardinalityOf(field.Type) + if err != nil { + errs = append(errs, fmt.Sprintf("%s.%s: %s fields are not supported", + t.Name(), field.Name, field.Type.String())) + return false + } - var err error - spec.cardinality, err = cardinalityOf(field.Type) - if err != nil { - errs = append(errs, fmt.Sprintf("%s.%s: %s fields are not supported", - t.Name(), field.Name, field.Type.String())) + defaultString, hasDefault := field.Tag.Lookup("default") + if hasDefault { + // we do not support default values for maps and slices + if spec.cardinality == multiple { + errs = append(errs, fmt.Sprintf("%s.%s: default values are not supported for slice or map fields", + t.Name(), field.Name)) return false } - if spec.cardinality == multiple && hasDefault { - errs = append(errs, fmt.Sprintf("%s.%s: default values are not supported for slice or map fields", + + // a required field cannot also have a default value + if spec.required { + errs = append(errs, fmt.Sprintf("%s.%s: 'required' cannot be used when a default value is specified", t.Name(), field.Name)) return false } + + // parse the default value + spec.defaultString = defaultString + if field.Type.Kind() == reflect.Pointer { + // here we have a field of type *T and we create a new T, no need to dereference + // in order for the value to be settable + spec.defaultValue = reflect.New(field.Type.Elem()) + } else { + // here we have a field of type T and we create a new T and then dereference it + // so that the resulting value is settable + spec.defaultValue = reflect.New(field.Type).Elem() + } + err := scalar.ParseValue(spec.defaultValue, defaultString) + if err != nil { + errs = append(errs, fmt.Sprintf("%s.%s: error processing default value: %v", t.Name(), field.Name, err)) + return false + } } + // add the spec to the list of specs + cmd.specs = append(cmd.specs, &spec) + // if this was an embedded field then we already returned true up above return false }) @@ -682,11 +697,8 @@ func (p *Parser) process(args []string) error { } return errors.New(msg) } - if spec.defaultVal != "" { - err := scalar.ParseValue(p.val(spec.dest), spec.defaultVal) - if err != nil { - return fmt.Errorf("error processing default value for %s: %v", name, err) - } + if spec.defaultValue.IsValid() { + p.val(spec.dest).Set(spec.defaultValue) } } diff --git a/parse_test.go b/parse_test.go index 4dcb806..7747d05 100644 --- a/parse_test.go +++ b/parse_test.go @@ -1321,13 +1321,21 @@ func TestDefaultOptionValues(t *testing.T) { require.NoError(t, err) assert.Equal(t, 123, args.A) - assert.Equal(t, 123, *args.B) + if assert.NotNil(t, args.B) { + assert.Equal(t, 123, *args.B) + } assert.Equal(t, "xyz", args.C) - assert.Equal(t, "abc", *args.D) + if assert.NotNil(t, args.D) { + assert.Equal(t, "abc", *args.D) + } assert.Equal(t, 4.56, args.E) - assert.Equal(t, 1.23, *args.F) - assert.True(t, args.G) + if assert.NotNil(t, args.F) { + assert.Equal(t, 1.23, *args.F) + } assert.True(t, args.G) + if assert.NotNil(t, args.H) { + assert.True(t, *args.H) + } } func TestDefaultUnparseable(t *testing.T) { @@ -1336,7 +1344,7 @@ func TestDefaultUnparseable(t *testing.T) { } err := parse("", &args) - assert.EqualError(t, err, `error processing default value for --a: strconv.ParseInt: parsing "x": invalid syntax`) + assert.EqualError(t, err, `.A: error processing default value: strconv.ParseInt: parsing "x": invalid syntax`) } func TestDefaultPositionalValues(t *testing.T) { @@ -1355,13 +1363,21 @@ func TestDefaultPositionalValues(t *testing.T) { require.NoError(t, err) assert.Equal(t, 456, args.A) - assert.Equal(t, 789, *args.B) + if assert.NotNil(t, args.B) { + assert.Equal(t, 789, *args.B) + } assert.Equal(t, "abc", args.C) - assert.Equal(t, "abc", *args.D) + if assert.NotNil(t, args.D) { + assert.Equal(t, "abc", *args.D) + } assert.Equal(t, 1.23, args.E) - assert.Equal(t, 1.23, *args.F) - assert.True(t, args.G) + if assert.NotNil(t, args.F) { + assert.Equal(t, 1.23, *args.F) + } assert.True(t, args.G) + if assert.NotNil(t, args.H) { + assert.True(t, *args.H) + } } func TestDefaultValuesNotAllowedWithRequired(t *testing.T) { @@ -1375,7 +1391,7 @@ func TestDefaultValuesNotAllowedWithRequired(t *testing.T) { func TestDefaultValuesNotAllowedWithSlice(t *testing.T) { var args struct { - A []int `default:"123"` // required not allowed with default! + A []int `default:"invalid"` // default values not allowed with slices } err := parse("", &args) @@ -16,9 +16,9 @@ var ( ) // cardinality tracks how many tokens are expected for a given spec -// - zero is a boolean, which does to expect any value -// - one is an ordinary option that will be parsed from a single token -// - multiple is a slice or map that can accept zero or more tokens +// - zero is a boolean, which does to expect any value +// - one is an ordinary option that will be parsed from a single token +// - multiple is a slice or map that can accept zero or more tokens type cardinality int const ( @@ -110,7 +110,7 @@ func isExported(field string) bool { // isZero returns true if v contains the zero value for its type func isZero(v reflect.Value) bool { t := v.Type() - if t.Kind() == reflect.Slice || t.Kind() == reflect.Map { + if t.Kind() == reflect.Pointer || t.Kind() == reflect.Slice || t.Kind() == reflect.Map || t.Kind() == reflect.Chan || t.Kind() == reflect.Interface { return v.IsNil() } if !t.Comparable() { diff --git a/usage_test.go b/usage_test.go index 0a7ddd8..10072c1 100644 --- a/usage_test.go +++ b/usage_test.go @@ -474,7 +474,7 @@ Options: ShortOnly2 string `arg:"-b,--,required" help:"some help2"` } p, err := NewParser(Config{Program: "example"}, &args) - assert.NoError(t, err) + require.NoError(t, err) var help bytes.Buffer p.WriteHelp(&help) |