title: FIREBASE WARNING: Invalid query string segment:
body: <p>I keep having these warnings in the Firebase Logs Console:
  "FIREBASE WARNING: Invalid query string segment:"</p>
  
  <p>I checked everything but I can't find some reasons.</p>
  
  <p>Do you have any ideas ?</p>
  
  <p>Configuration</p>
  
  <pre><code>{
  "name": "functions",
  "description": "Cloud Functions for Firebase",
  "dependencies": {
  "firebase-admin": "~5.8.1",
  "firebase-functions": "^0.8.1"
  },
  "private": true
  }
  </code></pre>
  
  <p>Test case: a very simple cloud function:</p>
  
  <pre><code>exports.test = functions.database
  .ref('/scores/{sportId}/{matchId}')
  .onWrite(event =&gt; {
  
  const sportId = event.params.sportId;
  const matchId = event.params.matchId;
  
  const awayTeamScore = event.data.child("awayTeamScore").val();
  const dateLastUpdate = event.data.child("dateLastUpdate").val();
  const homeTeamScore = event.data.child("homeTeamScore").val();
  const status = event.data.child("status").val();
  
  var awayTeamScoreSnapshot = event.data.child("awayTeamScore");
  var dateLastUpdateSnapshot = event.data.child("dateLastUpdate");
  var homeTeamScoreSnapshot = event.data.child("homeTeamScore");
  var statusSnapshot = event.data.child("status");
  
  return admin.database().ref(/indexMatchLeague/${matchId}).once('value').then(league =&gt; {
  console.log(matchId, homeTeamScore, awayTeamScore, status);
  /*
  var promises = [];
  league.forEach(leagueSnap =&gt; {
  const leagueId = leagueSnap.key;
  const leagueVal = leagueSnap.val();
  console.log(leagueId, leagueVal);
  });
  return Promise.all(promises);
  */
  return null;
  });
  });
  </code></pre>