From 90c8fc7888c3cca574a627f58d5c2b170e4e871e Mon Sep 17 00:00:00 2001
From: ahocevar <andreas.hocevar@gmail.com>
Date: Sun, 13 Jan 2019 23:09:24 +0100
Subject: [PATCH] Properly unregister prepareTile listeners

---
 src/ol/renderer/canvas/VectorTileLayer.js            | 10 ++++++++--
 test/spec/ol/renderer/canvas/vectortilelayer.test.js |  1 +
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/ol/renderer/canvas/VectorTileLayer.js b/src/ol/renderer/canvas/VectorTileLayer.js
index 4bee342199..9929c3fe9f 100644
--- a/src/ol/renderer/canvas/VectorTileLayer.js
+++ b/src/ol/renderer/canvas/VectorTileLayer.js
@@ -162,9 +162,14 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
    */
   prepareTile(tile, pixelRatio, projection) {
     const tileUid = getUid(tile);
-    if (tile.getState() === TileState.LOADED || tile.getState() === TileState.ERROR) {
+    const state = tile.getState();
+    if (((state === TileState.LOADED && tile.hifi) ||
+        state === TileState.ERROR || state === TileState.ABORT) &&
+        tileUid in this.tileListenerKeys_) {
       unlistenByKey(this.tileListenerKeys_[tileUid]);
       delete this.tileListenerKeys_[tileUid];
+    }
+    if (state === TileState.LOADED || state === TileState.ERROR) {
       this.updateExecutorGroup_(tile, pixelRatio, projection);
       if (this.tileImageNeedsRender_(tile, pixelRatio, projection)) {
         this.renderTileImageQueue_[tileUid] = tile;
@@ -177,13 +182,14 @@ class CanvasVectorTileLayerRenderer extends CanvasTileLayerRenderer {
    */
   getTile(z, x, y, pixelRatio, projection) {
     const tile = /** @type {import("../../VectorRenderTile.js").default} */ (super.getTile(z, x, y, pixelRatio, projection));
-    this.prepareTile(tile, pixelRatio, projection);
     if (tile.getState() < TileState.LOADED) {
       const tileUid = getUid(tile);
       if (!(tileUid in this.tileListenerKeys_)) {
         const listenerKey = listen(tile, EventType.CHANGE, this.prepareTile.bind(this, tile, pixelRatio, projection));
         this.tileListenerKeys_[tileUid] = listenerKey;
       }
+    } else {
+      this.prepareTile(tile, pixelRatio, projection);
     }
     return tile;
   }
diff --git a/test/spec/ol/renderer/canvas/vectortilelayer.test.js b/test/spec/ol/renderer/canvas/vectortilelayer.test.js
index 4ffb3365d8..b2b402e73e 100644
--- a/test/spec/ol/renderer/canvas/vectortilelayer.test.js
+++ b/test/spec/ol/renderer/canvas/vectortilelayer.test.js
@@ -281,6 +281,7 @@ describe('ol.renderer.canvas.VectorTileLayer', function() {
       layer.changed();
       renderer.renderFrame(frameState, {});
       expect(replayState.renderedTileRevision).to.be(revision + 1);
+      expect(Object.keys(renderer.tileListenerKeys_).length).to.be(0);
     });
   });