Fixes #1820: Normalise paths for checksum calls.

Author: frankdejonge

src/Filesystem.php

@@ -187,7 +187,10 @@ public function publicUrl(string $path, array $config = []): string
             ?? throw UnableToGeneratePublicUrl::noGeneratorConfigured($path);
         $config = $this->config->extend($config);
 
-        return $this->publicUrlGenerator->publicUrl($this->pathNormalizer->normalizePath($path), $config);
+        return $this->publicUrlGenerator->publicUrl(
+            $this->pathNormalizer->normalizePath($path),
+            $config,
+        );
     }
 
     public function temporaryUrl(string $path, DateTimeInterface $expiresAt, array $config = []): string
@@ -214,9 +217,15 @@ public function checksum(string $path, array $config = []): string
         }
 
         try {
-            return $this->adapter->checksum($path, $config);
+            return $this->adapter->checksum(
+                $this->pathNormalizer->normalizePath($path),
+                $config,
+            );
         } catch (ChecksumAlgoIsNotSupported) {
-            return $this->calculateChecksumFromStream($path, $config);
+            return $this->calculateChecksumFromStream(
+                $this->pathNormalizer->normalizePath($path),
+                $config,
+            );
         }
     }