String rawChildModelVersion = childModel.getVersion();

                if (rawChildModelVersion == null) {
                    // Message below is checked for in the MNG-2199 core IT.
                    problems.add(
                            Severity.FATAL,
                            ModelProblem.Version.V31,
                            "Version must be a constant",

                            if (logger.isDebugEnabled()) {
                                // Message below is checked for in the MNG-2199 core IT.
                                logger.warn("Failed to build parent project for " + project.getId(), e);
                            } else {
                                // Message below is checked for in the MNG-2199 core IT.