SolrCore.getNewIndexDir falsely returns {dataDir}/index on any IOException reading index.properties

I'll link the originating Solr JIRA in a minute (many thanks Nikolay).

right at the top of this method we have this:

String result = dataDir + "index/";

If, for any reason, the method doesn't complete properly, the "result" is still returned. Now for instance, down in SolrCore.cleanupOldIndexDirectories the "old" directory is dataDir/index which may point to the current index.

This seems particularly dangerous:

       try {
          p.load(new InputStreamReader(is, StandardCharsets.UTF_8));

          String s = p.getProperty("index");
          if (s != null && s.trim().length() > 0) {
              result = dataDir + s;
          }

        } catch (Exception e) {
          log.error("Unable to load " + IndexFetcher.INDEX_PROPERTIES, e);
        } finally {
          IOUtils.closeQuietly(is);
        }

Should "p.load" fail for any reason whatsoever, we'll still return dataDir/index.

Anyone want to chime on on what the expectations are here before I dive in?