feat: add TextFlag #2055

somebadcode · 2025-02-10T20:01:06Z

Added TextFlag which supports setting values for types that satisfies both encoding.TextMarshaller and encoding.TextUnmarshaller which is very handy when you want to set log levels or string-like types that satisfies the interfaces.

Fixes: #2051

What type of PR is this?

feature

What this PR does / why we need it:

Making it easier to set types that satisfies encoding.TextMarshaller and encoding.TextUnmarshaller such as log/slog.LogLevelVar, using flags as see in the standard library's flag.

Which issue(s) this PR fixes:

Fixes #2051

Release Notes

Added `TextFlag` to support setting values for types that satisfy both  `encoding.TextMarshaller` and `encoding.TextUnmarshaller`.

* Added `TextFlag` which supports setting values for types that satisfies the `encoding.TextMarshaller` and `encoding.TextUnmarshaller` which is very handy when you want to set log levels or string-like types that satifies the interfaces. Fixes: urfave#2051 Signed-off-by: Tobias Dahlberg <[email protected]>

Signed-off-by: Eng Zer Jun <[email protected]>

Juneezee

Thanks for your contribution! 😊

Just a few comments regarding the tests. If possible, please add a few more test cases to cover edge cases and improve coverage.

flag_text_test.go

Juneezee · 2025-02-11T10:06:03Z

flag_text_test.go

+			if err := tt.flag.Apply(set); err != nil {
+				t.Fatalf("Apply(%v) failed: %v", tt.args, err)
+			}
+
+			err := set.Parse(tt.args)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("Parse() error = %v, wantErr %v", err, tt.wantErr)
+
+				return
+			} else if (err != nil) == tt.wantErr {
+				// Expected error.
+				return
+			}
+
+			if got := tt.flag.GetValue(); got != tt.want {
+				t.Errorf("Value = %v, want %v", got, tt.want)
+			}


Use the testify package for assertions

I don't use testify and I don't see it as idiomatic Go.
But I've added it and I hope that I'm using it the correct way.

The tests should now have full coverage.

dearchap · 2025-02-11T14:42:54Z

flag_text.go

+	return v.Value
+}
+
+func (v TextValue) Create(t TextMarshalUnMarshaller, _ *TextMarshalUnMarshaller, c StringConfig) Value {


Suggested change

func (v TextValue) Create(t TextMarshalUnMarshaller, _ *TextMarshalUnMarshaller, c StringConfig) Value {

func (v TextValue) Create(t TextMarshalUnMarshaller, p *TextMarshalUnMarshaller, c StringConfig) Value {

b, _ := p.MarshalText()

t.UnmarshalText(b)

I've made the necessary changes.

dearchap · 2025-02-11T14:43:43Z

flag_text.go

+type TextFlag = FlagBase[TextMarshalUnMarshaller, StringConfig, TextValue]
+
+type TextValue struct {
+	Value  TextMarshalUnMarshaller


Suggested change

Value TextMarshalUnMarshaller

Value *TextMarshalUnMarshaller

I've made the necessary changes.

dearchap · 2025-02-11T14:43:57Z

flag_text.go

+
+func (v TextValue) Create(t TextMarshalUnMarshaller, _ *TextMarshalUnMarshaller, c StringConfig) Value {
+	return &TextValue{
+		Value:  t,


Suggested change

Value: t,

Value: p,

I've made the necessary changes.

dearchap · 2025-02-11T14:44:44Z

flag_text.go

+
+func (v TextValue) Set(s string) error {
+	if v.Config.TrimSpace {
+		return v.Value.UnmarshalText([]byte(strings.TrimSpace(s)))


Suggested change

return v.Value.UnmarshalText([]byte(strings.TrimSpace(s)))

s = strings.TrimSpace(s)

I've made the necessary changes.

dearchap · 2025-02-11T14:48:01Z

flag_text_test.go

+			name: "empty",
+			flag: TextFlag{
+				Name:  "log-level",
+				Value: &slog.LevelVar{},


Note that Value is used to initialize the flag. The actual value of field should be in Destination

See the flag_generic.go as an example.

I've addressed this in the latest version of the PR.

Signed-off-by: Eng Zer Jun <[email protected]>

somebadcode · 2025-02-13T19:04:21Z

I've discovered a limitation of the way the FlagBase forces you to have T and *T. That's not suitable in this case when when it would be better for it to be encoding.TextMarshaler and encoding.TextUnmarshaler.

So the interface that I created does not equate to those two to the extent that it allows the user of the package to just put their implementation in like you can with flag.TextVar.

	text := &MockMarshaller{}

	cmd := &Command{
		Name: "foo",
		Flags: []Flag{
			&TextFlag{
				Name:        "mytext",
				Value:       text,
				Destination: &text,
			},
		},
	}

This is not valid. Because &text is of type **MockMarshaller and not *TextMarshaler. Type assertion for a simple case like this is unpleasant.

So I would either have to not use the FlagBase and re-implement everything that it gives or FlagBase must be refactored to allow for two disparate types to be used for value and destination like flag.TextVar does.

dearchap · 2025-02-13T22:02:17Z

@somebadcode can you send me the test code you are using for this ? I think it should be like this.

	text := MockMarshaller{}

	cmd := &Command{
		Name: "foo",
		Flags: []Flag{
			&TextFlag{
				Name:        "mytext",
				Value:       text,
				Destination: &text,
			},
		},
	}

somebadcode · 2025-02-13T23:35:12Z

@somebadcode can you send me the test code you are using for this ? I think it should be like this.
	text := MockMarshaller{}

	cmd := &Command{
		Name: "foo",
		Flags: []Flag{
			&TextFlag{
				Name:        "mytext",
				Value:       text,
				Destination: &text,
			},
		},
	}

Test code:

type MockMarshaller struct {
	text []byte
}

var _ encoding.TextMarshaler = (*MockMarshaller)(nil)
var _ encoding.TextUnmarshaler = (*MockMarshaller)(nil)

func (m *MockMarshaller) MarshalText() ([]byte, error) {
	return m.text, nil
}

func (m *MockMarshaller) UnmarshalText(text []byte) error {
	m.text = text
	return nil
}

func TestTextFlagValueFromCommand(t *testing.T) {
	text := &MockMarshaller{}

	cmd := &Command{
		Name: "foo",
		Flags: []Flag{
			&TextFlag{
				Name:        "mytext",
				Value:       text,
				Destination: &text,
			},
		},
	}
}

Code that I'm trying to test:

func (cmd *Command) Text(name string) TextMarshalUnmarshaler {
	if v, ok := cmd.Value(name).(TextMarshalUnmarshaler); ok {
		tracef("text available for flag name %[1]q with value=%[2]v (cmd=%[3]q)", name, v, cmd.Name)
		return v
	}

	tracef("text NOT available for flag name %[1]q (cmd=%[2]q)", name, cmd.Name)
	return nil
}

This is what I've added but not committed yet.

somebadcode requested a review from a team as a code owner February 10, 2025 20:01

docs: update godoc

0cd35b5

Signed-off-by: Eng Zer Jun <[email protected]>

Juneezee force-pushed the textflag branch from 1df6b84 to 0cd35b5 Compare February 11, 2025 09:50

Juneezee reviewed Feb 11, 2025

View reviewed changes

somebadcode added 4 commits February 11, 2025 13:21

fix: use stretchr/{assert,require}

215d8c7

fix: improve test coverage of TextFlag

3475c74

fix: remove underscore receiver

dd20af7

fix: remove superfluous empty line

de9fde3

dearchap reviewed Feb 11, 2025

View reviewed changes

fix: address review feedback

33d1db5

somebadcode force-pushed the textflag branch from 0876e6b to 33d1db5 Compare February 11, 2025 23:16

somebadcode added 2 commits February 12, 2025 23:50

fix: address review feedback and update doc

ff22a37

fix: adjust docs to reflect changes

35656a1

somebadcode force-pushed the textflag branch from d9552c8 to 35656a1 Compare February 12, 2025 22:56

docs: regenerate v3 godoc

9b87f3b

Signed-off-by: Eng Zer Jun <[email protected]>

Juneezee approved these changes Feb 13, 2025

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feat: add TextFlag #2055

feat: add TextFlag #2055

somebadcode commented Feb 10, 2025 •

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somebadcode Feb 13, 2025 •

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somebadcode commented Feb 13, 2025

dearchap commented Feb 13, 2025

somebadcode commented Feb 13, 2025

-func (v TextValue) Create(t TextMarshalUnMarshaller, _ *TextMarshalUnMarshaller, c StringConfig) Value {
+func (v TextValue) Create(t TextMarshalUnMarshaller, p *TextMarshalUnMarshaller, c StringConfig) Value {
+      b, _ := p.MarshalText()
+      t.UnmarshalText(b)

	return v.Value.UnmarshalText([]byte(strings.TrimSpace(s)))
	s = strings.TrimSpace(s)

feat: add TextFlag #2055

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feat: add TextFlag #2055

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somebadcode commented Feb 10, 2025 • edited Loading

What type of PR is this?

What this PR does / why we need it:

Which issue(s) this PR fixes:

Release Notes

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