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add unknown flags support #285

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9cd59d2
add unknown flags support
Jun 23, 2020
33dec6a
fixing test
TiboStev Sep 18, 2020
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103 changes: 68 additions & 35 deletions flag.go
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Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,7 @@ type FlagSet struct {
normalizeNameFunc func(f *FlagSet, name string) NormalizedName

addedGoFlagSets []*goflag.FlagSet
unknownFlags []*Flag
}

// A Flag represents the state of a flag.
Expand All @@ -182,6 +183,12 @@ type Flag struct {
Annotations map[string][]string // used by cobra.Command bash autocomple code
}

// A UnknownFlag represents the state of a flag that is not expected.
type UnknownFlag struct {
Name string // name as it appears on command line
Value Value // value as set
}

// Value is the interface to the dynamic value stored in a flag.
// (The default value is represented as a string.)
type Value interface {
Expand Down Expand Up @@ -275,6 +282,17 @@ func (f *FlagSet) SetOutput(output io.Writer) {
f.output = output
}

// VisitUnknowns visits all the flags that have not been registered.
func (f *FlagSet) VisitUnknowns(fn func(*Flag)) {
if len(f.unknownFlags) == 0 {
return
}

for _, flag := range f.unknownFlags {
fn(flag)
}
}

// VisitAll visits the flags in lexicographical order or
// in primordial order if f.SortFlags is false, calling fn for each.
// It visits all flags, even those not set.
Expand Down Expand Up @@ -956,6 +974,18 @@ func stripUnknownFlagValue(args []string) []string {
return nil
}

func createUnknownFlag(name string, value string) *Flag {
flag := new(Flag)
flag.Name = name
flag.Value = newStringValue(value, &value)
return flag
}

func (f *FlagSet) addUnknownFlag(name string, value string) {
flag := createUnknownFlag(name, value)
f.unknownFlags = append(f.unknownFlags, flag)
}

func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []string, err error) {
a = args
name := s[2:]
Expand All @@ -969,19 +999,11 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
flag, exists := f.formal[f.normalizeFlagName(name)]

if !exists {
switch {
case name == "help":
if name == "help" {
f.usage()
return a, ErrHelp
case f.ParseErrorsWhitelist.UnknownFlags:
// --unknown=unknownval arg ...
// we do not want to lose arg in this case
if len(split) >= 2 {
return a, nil
}

return stripUnknownFlagValue(a), nil
default:
}
if !f.ParseErrorsWhitelist.UnknownFlags {
err = f.failf("unknown flag: --%s", name)
return
}
Expand All @@ -991,16 +1013,23 @@ func (f *FlagSet) parseLongArg(s string, args []string, fn parseFunc) (a []strin
if len(split) == 2 {
// '--flag=arg'
value = split[1]
} else if flag.NoOptDefVal != "" {
} else if exists && flag.NoOptDefVal != "" {
// '--flag' (arg was optional)
value = flag.NoOptDefVal
} else if len(a) > 0 {
// '--flag arg'
value = a[0]
a = a[1:]
} else {
// '--flag' (arg was required)
err = f.failf("flag needs an argument: %s", s)
if !exists && strings.HasPrefix(a[0], "-") {
value = ""
} else {
value = a[0]
a = a[1:]
}
} else if f.ParseErrorsWhitelist.UnknownFlags {
value = ""
}

if !exists && f.ParseErrorsWhitelist.UnknownFlags {
f.addUnknownFlag(name, value)
return
}

Expand All @@ -1023,22 +1052,12 @@ func (f *FlagSet) parseSingleShortArg(shorthands string, args []string, fn parse

flag, exists := f.shorthands[c]
if !exists {
switch {
case c == 'h':
if c == 'h' {
f.usage()
err = ErrHelp
return
case f.ParseErrorsWhitelist.UnknownFlags:
// '-f=arg arg ...'
// we do not want to lose arg in this case
if len(shorthands) > 2 && shorthands[1] == '=' {
outShorts = ""
return
}

outArgs = stripUnknownFlagValue(outArgs)
return
default:
}
if !f.ParseErrorsWhitelist.UnknownFlags {
err = f.failf("unknown shorthand flag: %q in -%s", c, shorthands)
return
}
Expand All @@ -1049,18 +1068,32 @@ func (f *FlagSet) parseSingleShortArg(shorthands string, args []string, fn parse
// '-f=arg'
value = shorthands[2:]
outShorts = ""
} else if flag.NoOptDefVal != "" {
// '-f' (arg was optional)
} else if exists && flag.NoOptDefVal != "" {
// '--flag' (arg was optional)
value = flag.NoOptDefVal
} else if len(shorthands) > 1 {
// '-farg'
value = shorthands[1:]
outShorts = ""
} else if len(args) > 0 {
// '-f arg'
value = args[0]
outArgs = args[1:]
} else {
if !exists && strings.HasPrefix(args[0], "-") {
value = ""
} else {
value = args[0]
outArgs = args[1:]
}

} else if f.ParseErrorsWhitelist.UnknownFlags {
value = ""
}

if !exists && f.ParseErrorsWhitelist.UnknownFlags {
f.addUnknownFlag(string(c), value)
return
}

if flag.NoOptDefVal == "" && value == "" {
// '-f' (arg was required)
err = f.failf("flag needs an argument: %q in -%s", c, shorthands)
return
Expand Down
63 changes: 63 additions & 0 deletions flag_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -480,6 +480,68 @@ func testParseWithUnknownFlags(f *FlagSet, t *testing.T) {
}
}

func testRetrieveUknowsWhenUnknownFlagsParsed(t *testing.T) {
f := NewFlagSet("unknwonFlags", ContinueOnError)
if f.Parsed() {
t.Error("f.Parse() = true before Parse")
}
boolaFlag := f.BoolP("boola", "a", false, "bool value")
stringaFlag := f.StringP("stringa", "s", "0", "string value")

args := []string{
"-a",
"--stringa",
"hello",
"--unknownFlag1",
"unknownValue1",
"--unknownFlag2",
"--unknownFlag3=unknownValue3",
"-e",
"unknownValue4",
"-f=unknownValue5",
"-g",
}

f.ParseErrorsWhitelist.UnknownFlags = true

want := map[string]string{
"unknownFlag1": "unknownValue1",
"unknownFlag2": "",
"unknownFlag3": "unknownValue3",
"e": "unknownValue4",
"f": "unknownValue5",
"g": "",
}

f.SetOutput(ioutil.Discard)
if err := f.Parse(args); err != nil {
t.Error("expected no error, got ", err)
}
if !f.Parsed() {
t.Error("f.Parse() = false after Parse")
}
if *boolaFlag != true {
t.Error("boola flag should be true, is ", *boolaFlag)
}
if *stringaFlag != "hello" {
t.Error("stringa flag should be `hello`, is ", *stringaFlag)
}
if len(f.unknownFlags) != len(want) {
t.Errorf("f.ParseAll() failed to parse unknown flags")
}
for _, flag := range f.unknownFlags {
wantedValue, ok := want[flag.Name]
if !ok {
t.Errorf("f.unknownFlags contains a flag \"%s\" and shouldn't", flag.Name)
break
}
if wantedValue != flag.Value.String() {
t.Errorf("value for the unknown flag \"%s\" should be \"%s\", got \"%s\"", flag.Name, wantedValue, flag.Value.String())
}

}
}

func TestShorthand(t *testing.T) {
f := NewFlagSet("shorthand", ContinueOnError)
if f.Parsed() {
Expand Down Expand Up @@ -588,6 +650,7 @@ func TestParseAll(t *testing.T) {

func TestIgnoreUnknownFlags(t *testing.T) {
ResetForTesting(func() { t.Error("bad parse") })
testRetrieveUknowsWhenUnknownFlagsParsed(t)
testParseWithUnknownFlags(GetCommandLine(), t)
}

Expand Down