Preserve structured diagnostics and candidate error context

cmd/releasekit/main.go

@@ -155,10 +155,6 @@ func candidateRequest(invocation cli.Invocation, settings cli.Settings, output i
 }
 
 func candidateFailureText(err error) string {
-	var validationError *releasekit.ValidationError
-	if errors.As(err, &validationError) {
-		return validationError.Error()
-	}
 	return err.Error()
 }
 

cmd/releasekit/main_test.go

@@ -17,6 +17,7 @@ import (
 	"strings"
 	"testing"
 
+	releasekit "gitea.maximumdirect.net/eric/ReleaseKit"
 	"gitea.maximumdirect.net/eric/ReleaseKit/buildinfo"
 	"gitea.maximumdirect.net/eric/ReleaseKit/cmd/releasekit/internal/cli"
 )
@@ -149,6 +150,20 @@ func TestCandidateCommandsPresentValidationDiagnosticsOnce(t *testing.T) {
 	}
 }
 
+func TestCandidateFailurePresentationRetainsCallbackContext(t *testing.T) {
+	diagnostic := &releasekit.ValidationError{
+		Check:    "examples",
+		Findings: []releasekit.ValidationFinding{{Path: "examples/run/main.go", Message: "unexpected output"}},
+	}
+	err := fmt.Errorf("validate candidate captured-commit: %w", diagnostic)
+	text := candidateFailureText(err)
+	for _, part := range []string{"captured-commit", "examples", "examples/run/main.go", "unexpected output"} {
+		if !strings.Contains(text, part) {
+			t.Errorf("CLI presentation %q omits %q", text, part)
+		}
+	}
+}
+
 func TestPublishCommandPublishesConfiguredCandidate(t *testing.T) {
 	repository := newCLIRepository(t)
 	writeRepositoryFile(t, repository, "docs/releases/v1.2.3.md", "# Example Product v1.2.3\n\n## Compatibility\n\nNo action required.\n")