Fix the issue #5

docs.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"reflect"
 	"regexp"
 	"runtime"
 	"sort"
@@ -277,7 +278,7 @@ func prepareFlags(
 // flagDetails returns a string containing the flags metadata
 func flagDetails(flag cli.DocGenerationFlag) string {
 	description := flag.GetUsage()
-	value := flag.GetValue()
+	value := getFlagDefaultValue(flag)
 	if value != "" {
 		description += " (default: " + value + ")"
 	}
@@ -404,7 +405,7 @@ func (tt tabularTemplate) PrepareFlags(flags []cli.Flag) []cliTabularFlagTemplat
 			Usage:      tt.PrepareMultilineString(flag.GetUsage()),
 			EnvVars:    flag.GetEnvVars(),
 			TakesValue: flag.TakesValue(),
-			Default:    flag.GetValue(),
+			Default:    getFlagDefaultValue(flag),
 		}
 
 		if boolFlag, isBool := appFlag.(*cli.BoolFlag); isBool {
@@ -554,3 +555,34 @@ func (tabularTemplate) Prettify(s string) string {
 
 	return s + "\n" // add an extra newline
 }
+
+// getFlagDefaultValue returns the default value of a flag. Previously, the [cli.DocGenerationFlag] interface included
+// a GetValue string method, but it was removed in https://github.com/urfave/cli/pull/1988.
+// This function serves as a workaround, attempting to retrieve the value using the removed method; if that fails, it
+// tries to obtain it via reflection (the [cli.FlagBase] still has a Value field).
+func getFlagDefaultValue(f cli.DocGenerationFlag) string {
+	if !f.TakesValue() {
+		return ""
+	}
+
+	if v, ok := f.(interface{ GetValue() string }); ok {
+		return v.GetValue()
+	}
+
+	var ref = reflect.ValueOf(f)
+	if ref.Kind() != reflect.Ptr {
+		return ""
+	} else {
+		ref = ref.Elem()
+	}
+
+	if ref.Kind() != reflect.Struct {
+		return ""
+	}
+
+	if val := ref.FieldByName("Value"); val.IsValid() && val.Type().Kind() != reflect.Bool {
+		return fmt.Sprintf("%v", val.Interface())
+	}
+
+	return ""
+}

go.mod

@@ -4,14 +4,13 @@ go 1.18
 
 require (
 	github.com/cpuguy83/go-md2man/v2 v2.0.2
-	github.com/stretchr/testify v1.8.4
-	github.com/urfave/cli/v3 v3.0.0-alpha4
+	github.com/stretchr/testify v1.9.0
+	github.com/urfave/cli/v3 v3.0.0-alpha9.2
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
-	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -6,12 +6,10 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/russross/blackfriday/v2 v2.1.0 h1:JIOH55/0cWyOuilr9/qlrm0BSXldqnqwMsf35Ld67mk=
 github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
-github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
-github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-github.com/urfave/cli/v3 v3.0.0-alpha4 h1:RJFGIs3mcalmc2YgliDh0Pa4l79S+Dqdz7cW8Fcp7Rg=
-github.com/urfave/cli/v3 v3.0.0-alpha4/go.mod h1:ZFqSEHhze0duJACOdz43I5IcnKhf4RoTlOoUMBUggOI=
-github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 h1:bAn7/zixMGCfxrRTfdpNzjtPYqr8smhKouy9mxVdGPU=
-github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673/go.mod h1:N3UwUGtsrSj3ccvlPHLoLsHnpR27oXr4ZE984MbSER8=
+github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
+github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/urfave/cli/v3 v3.0.0-alpha9.2 h1:CL8llQj3dGRLVQQzHxS+ZYRLanOuhyK1fXgLKD+qV+Y=
+github.com/urfave/cli/v3 v3.0.0-alpha9.2/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=