From 1702cafa1c2bb3044f24497ef6eab7869f1edcc6 Mon Sep 17 00:00:00 2001
From: Jim Phillips <jcphill@users.noreply.github.com>
Date: Wed, 2 Aug 2023 10:11:19 -0500
Subject: [PATCH] Cache fetch promise and clear on error

---
 src/geotiffimage.js | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/geotiffimage.js b/src/geotiffimage.js
index 7b889262..2918926f 100644
--- a/src/geotiffimage.js
+++ b/src/geotiffimage.js
@@ -382,12 +382,12 @@ class GeoTIFFImage {
       offset = this.fileDirectory.StripOffsets[index];
       byteCount = this.fileDirectory.StripByteCounts[index];
     }
-    const slice = (await this.source.fetch([{ offset, length: byteCount }], signal))[0];
 
     let request;
     if (tiles === null || !tiles[index]) {
     // resolve each request by potentially applying array normalization
       request = (async () => {
+        const slice = (await this.source.fetch([{ offset, length: byteCount }], signal))[0];
         let data = await poolOrDecoder.decode(this.fileDirectory, slice);
         const sampleFormat = this.getSampleFormat();
         const bitsPerSample = this.getBitsPerSample();
@@ -408,6 +408,11 @@ class GeoTIFFImage {
       // set the cache
       if (tiles !== null) {
         tiles[index] = request;
+        request.catch(() => {
+          if ( tiles[index] === request ) {
+            tiles[index] = null;
+          }
+        });
       }
     } else {
       // get from the cache