Present help failures through the common diagnostic path

docs/roadmap/remediation.md

@@ -54,6 +54,9 @@ architecture. The issues below affect behavior within the implemented structure.
 - R-03 complete: standard inspection handlers check cancellation before runtime
   construction/acquisition, after acquisition, and before prepared report delivery.
 
+- R-04 complete: every help entry form finalizes report failures through the
+  common diagnostic presentation path once.
+
 ## Findings and priority
 
 P1 means a supported invocation is blocked or its report content is corrupted.

execute.go

@@ -29,13 +29,13 @@ func (a *App) Execute(ctx context.Context, args []string, streams Streams) Outco
 	}
 	command, ok := a.commandAt(parsed.Path)
 	if !ok || command.payload == nil {
-		return a.renderHelpOutcome(parsed.Path, streams)
+		return a.present(a.renderHelpOutcome(parsed.Path, streams), parsed.Path, streams)
 	}
 	if parsed.HelpRequested || !command.payload.hasRun() {
 		if _, err := command.payload.prepare(parsed.FlagValues, parsed.Operands, false); err != nil {
 			return a.present(Usage(err), parsed.Path, streams)
 		}
-		return a.renderHelpOutcome(parsed.Path, streams)
+		return a.present(a.renderHelpOutcome(parsed.Path, streams), parsed.Path, streams)
 	}
 	buildInput, err := command.payload.prepare(parsed.FlagValues, parsed.Operands, true)
 	if err != nil {

execute_external_test.go

@@ -413,3 +413,27 @@ func (shortWriter) Write(data []byte) (int, error) {
 	}
 	return len(data) - 1, nil
 }
+
+func TestHelpEntryFormsPresentReportAndDiagnosticFailures(t *testing.T) {
+	group, err := commandkit.Group("notes", "Notes metadata.")
+	if err != nil {
+		t.Fatal(err)
+	}
+	app, err := commandkit.New(commandkit.Identity{Name: "example"}, group)
+	if err != nil {
+		t.Fatal(err)
+	}
+	reportErr := errors.New("report failed")
+	diagnosticErr := errors.New("diagnostic failed")
+	for _, args := range [][]string{nil, {"notes"}, {"--help"}, {"-h"}, {"notes", "--help"}, {"help"}, {"help", "notes"}} {
+		var diagnostics bytes.Buffer
+		result := app.Execute(context.Background(), args, commandkit.Streams{Out: failingWriter{reportErr}, Err: &diagnostics})
+		if result.Kind != commandkit.OutcomeOperational || !result.ReportIncomplete || !errors.Is(result.Cause, reportErr) || !errors.Is(result.DeliveryError, reportErr) || result.DiagnosticDelivery != commandkit.DeliveryComplete || strings.Count(diagnostics.String(), reportErr.Error()) != 1 {
+			t.Fatalf("%v: result=%#v diagnostics=%q", args, result, diagnostics.String())
+		}
+		result = app.Execute(context.Background(), args, commandkit.Streams{Out: failingWriter{reportErr}, Err: failingWriter{diagnosticErr}})
+		if result.DiagnosticDelivery != commandkit.DeliveryIncomplete || !errors.Is(result.Cause, reportErr) || !errors.Is(result.DeliveryError, reportErr) || !errors.Is(result.DeliveryError, diagnosticErr) {
+			t.Fatalf("%v: result=%#v", args, result)
+		}
+	}
+}