Accept shared debug bindings

internal/commandmeta/metadata.go

@@ -2,6 +2,8 @@
 // its command-line backend.
 package commandmeta
 
+import "strings"
+
 // Key identifies one command inside one routing snapshot.
 type Key uint64
 
@@ -100,6 +102,35 @@ func ReportingFlags() []Flag {
 	return flags
 }
 
+// EffectiveFlags combines the shared debug option while preserving consumer order.
+func EffectiveFlags(flags, core []Flag) []Flag {
+	result := append([]Flag(nil), flags...)
+	shared := -1
+	for i, flag := range result {
+		if flag.Name == "debug" && flag.Boolean {
+			shared = i
+			break
+		}
+	}
+	for _, flag := range core {
+		if flag.Name == "debug" && shared >= 0 {
+			app := result[shared]
+			usage := flag.Usage
+			if app.Usage != "" {
+				usage += "; " + app.Usage
+			}
+			if strings.EqualFold(app.Default, "true") {
+				usage += "; application input defaults to true (reporting defaults to ordinary)"
+			}
+			flag.Usage, flag.Short, flag.Required, flag.Completion = usage, app.Short, app.Required, app.Completion
+			result[shared] = flag
+			continue
+		}
+		result = append(result, flag)
+	}
+	return result
+}
+
 // IsReportingFlag reports whether name is reserved for a shared reporting flag.
 func IsReportingFlag(name string) bool {
 	for _, flag := range reportingFlags {

internal/commandmeta/metadata_test.go

@@ -1,6 +1,9 @@
 package commandmeta
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestReportingFlagsAreBooleanAndReturnedIndependently(t *testing.T) {
 	flags := ReportingFlags()
@@ -33,3 +36,15 @@ func TestReportingFlagsAreBooleanAndReturnedIndependently(t *testing.T) {
 		}
 	}
 }
+
+func TestEffectiveFlagsCombinesDebugMetadata(t *testing.T) {
+	flags := []Flag{{Name: "before"}, {Name: "debug", Short: "d", Boolean: true, Default: "true", Required: true, Usage: "application diagnostics", Completion: CompletionHint{Kind: CompletionFiles}}, {Name: "after"}}
+	core := ReportingFlags()
+	got := EffectiveFlags(flags, core)
+	if len(got) != len(flags)+len(core)-1 || got[1].Name != "debug" || got[1].Default != "false" || got[1].Short != "d" || !got[1].Required || got[1].Completion.Kind != CompletionFiles || !strings.Contains(got[1].Usage, "application diagnostics") || !strings.Contains(got[1].Usage, "application input defaults to true") {
+		t.Fatalf("effective debug = %#v", got)
+	}
+	if flags[1].Default != "true" || core[2].Short != "" {
+		t.Fatal("input metadata changed")
+	}
+}