Unify previous source resolution

internal/app/operator_session_validate.go

@@ -57,12 +57,14 @@ func SessionValidate(ctx context.Context, args []string, out io.Writer) error {
 	previous := inspectPreviousArtifactReadiness(ctx, cfg, store, requirements)
 	if len(previous.Requirements) == 0 {
 		findings = append(findings, okFinding("previous", "no previous-session artifacts required"))
-	} else if previous.MissingID {
-		findings = append(findings, errorFinding("previous", "previous_session_id is required by configured previous-session artifacts"))
 	} else if previous.Err != nil {
 		findings = append(findings, errorFinding("previous", previous.Err.Error()))
 	} else {
 		for _, req := range previous.Requirements {
+			if !req.Required && previousRequirementSkipped(previous.SkippedMissing, req.Name) {
+				findings = append(findings, okFinding("previous", fmt.Sprintf("%s required=false unavailable", req.Name)))
+				continue
+			}
 			findings = append(findings, okFinding("previous", fmt.Sprintf("%s required=%t", req.Name, req.Required)))
 		}
 	}
@@ -82,3 +84,12 @@ func SessionValidate(ctx context.Context, args []string, out io.Writer) error {
 	}
 	return renderFindings(out, cfg.Session.Campaign, cfg.Session.SessionID, findings)
 }
+
+func previousRequirementSkipped(values []string, name string) bool {
+	for _, value := range values {
+		if value == name {
+			return true
+		}
+	}
+	return false
+}